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Management of low angle case in orthodontics

low angle case

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Management of low angle case in orthodontics

  1. 1. Management of low angle case 1 Dr Ravikanth Lakkakula
  2. 2. Contents 1. Introduction 2. Etiology 3. Clinical and Diagnostic Features 4. Management A)Removable Appliances B)Growth Modification Methods C) Magnets D)Fixed Appliances E)Implants. F)Bite Plate Effect (lingual appliance). G)Invisalign virtual bite ramps. H)Surgical Treatment 5. Stability and Retention 6. Conclusion 7. References 2 Dr Ravikanth Lakkakula
  3. 3. Introduction Hypodivergent faces means short face or low angle case. Skeletal Deep bite is one of the frequently seen malocclusions, occur along with other associated malocclusions. It is said to be one of the most perpetuating and damaging malocclusions . It may jeopardize the periodontal support, occlusion itself or TMJ. The excessive overbite is a complex orthodontic problem that may involve a group of teeth or whole dentition, alveolar bone, of maxillary and mandibular basal bones and / or soft tissue of the face . The management of this problem demands a careful diagnostic analysis, treatment plan and selection of appropriate treatment therapy. 3 Dr Ravikanth Lakkakula
  4. 4. Overbite is related to the growth of the jaws and the rate of eruption of incisor teeth. It decreases from the primary dentition to the permanent dentition by the upper and lower first permanent molars eruption . Proprioceptive response conditions the patient against biting on this natural bite opener, and thus the deciduous teeth anterior to the first permanent molars erupt, thus reducing the overbite. The short anterior vertical facial height type with a low mandibular plane and the most extreme incisor overbites are those that would best benefit from mandibular rotation, but their strong musculature function resists the molar extrusion . 4 Dr Ravikanth Lakkakula
  5. 5. The skeletal deep bite is characterized by a horizontal growth pattern. The anterior facial height is short, particularly the lower facial third , where as posterior facial height is long. Although the normal ratio of upper to lower anterior facial height is 2:3 , it is reduced in the skeletal overbite to a ratio of 2 : 2.5 to 2 : 2.8. The inclination of the maxillary base is significant in the evaluation of the treatment plan for this type of problem. An extreme horizontal growth pattern can be at least partially compensated by an up and forward inclination of the maxillary (ante inclination). On other hand , the combination of horizontal pattern with a down and forward inclination (retroclination) of maxillary base results in a more severe skeletal deep overbite. 5 Dr Ravikanth Lakkakula
  6. 6. It is multi factorial. Skeletal type of overbite may be either due to malrelationships of alveolar bones and/or underlying mandibular or maxillary bones or to an overgrowth or undergrowth of one or more alveolar segments. Hereditary and may follow a genetic pattern or familial Condition (autosomal dominant). The class II division 2 pattern is known to have a strong familial occurrence. Peck and Peck called it , heritable pattern of small teeth in well developed jaws. According to their findings, the pattern of strong vertical posterior development of mandible with upward and forward rotation and Etiology 6 Dr Ravikanth Lakkakula
  7. 7. 7 Skeletofacial hypodivergence anterioposteriorly, smaller mesiodistal tooth diameters for the maxillary and mandibular incisors are characteristic pattern of heritable skeletal and tooth size features in class II division 2 overbite malocclusion. These findings indicate the strong genetic influence in the formation of angle class II division 2 deep bite discrepancy. Ruf and Pancherz have reported a pair of monozygotic twins showing malocclusion discordance with a class II division 1 malocclusion in one(MSX 1) and division 2 another(MSX 2) . Based on this report , they have hypothesized that hereditary is not the sole etiological factor of class II division 2 malocclusion, as normally one would expect similar occlusion in monozygotic twins. Dr Ravikanth Lakkakula
  8. 8. 8 Studies in twins with class II div 2 showed that monozygotic twins displayed high concordance within malocclusion features, while dizygotic twins showed 90% discordance in these features (Mossey, 1999). Dr Ravikanth Lakkakula
  9. 9. A Detailed clinical examination of the dentition, occlusion, jaw movements and soft tissue pattern of face is very important. For an adolescent patient, a lateral Cephalograms must be taken to study the skeletal, dental and soft tissue relationship and the growth pattern and its status. CLINICAL AND DIAGNOSTIC FEATURES 9 Dr Ravikanth Lakkakula
  10. 10. 1. CLINICAL FEATURES A) Extra Oral features 1. Patient has a short, square face and an edentulous appearance. 2. When the jaws are at rest, or when the patient is speaking or Smiling, the maxillary incisors are hidden behind the upper lip. 3. The upper lip curves downward and the corners of mouth are below the occlusal line. 4. When the mandible is in centric occlusion, distinct skin folds are seen lateral to the oral commissure. 10 Dr Ravikanth Lakkakula
  11. 11. 5. Upper third of face is within normal limits. 6. A study of the middle third of the face shows broad nasal alar bases and large nostrils. 7. The posterior part of face appears wide because of prominent mandibular angles. 8. The lips are thin and with an excess of lip height relative to face height. This gives a curled appearance of the lips. 11 Dr Ravikanth Lakkakula
  12. 12. 9.. The Naso -labial angle is essentially normal or obtuse. 10. With the mandible in a rest position and the upper lip relaxed, the incisal edges of the maxillary anterior teeth are positioned above the inferior margin of upper lip. 11. There is distinct chin button, which is made more apparent by a deep mento labial fold and hyper active lowerlip. 12 Dr Ravikanth Lakkakula
  13. 13. 12. Upper tooth to upper lip relationship is a vertical measurement made in midline from the incisal edges of maxillary central incisor to the most inferior portion of the upper lip. Usually this distance is 2-5 mm. If the upper teeth are buried under the upper lip, it indicates skeletal deep bite. 13. Inter labial distance is the vertical distance between the most inferior portion of the upper and lower lip when the lips are relaxed and the teeth are in centric relation. In normal individual it is approximately 2mm. Decreased inter labial distance or redundancy of the lips indicates skeletal deep bite. 13 Dr Ravikanth Lakkakula
  14. 14. B) Intraoral features 1. The maxillary arch is broad and the palatal vault is typically flat. 2. Majority of the problems in this category are created by premature loss of permanent teeth causing a lingual collapse of maxillary or mandibular anterior teeth. Similarly loss and / or mesial tipping of the posterior teeth may also cause a deepening of the overbite, primarily due to a decrease in the vertical height of the face. 3. In class II division 2 , maxillary central incisors are retroclined and labial inclination of laterals, have short root , longer crown, axial bending of incisors , reduced labiopalatal thickness, 12 ˚ more vertically placed , decreased collum angle between crown and root and class II molar and canine relationship. 4. Large inter occlusal space. 5. In the mandibular dentition it may manifest as a deep curve of spee or reverse curve of spee in the maxillary dentition. 14 Dr Ravikanth Lakkakula
  15. 15. 2. Cephalometric findings 1. Decreased Go–Gn angle. 2. Decreased occlusal plane angle. 3. Decreased Y – Axis. 4. Decreased FMAAngle. 5. Decreased Articular angle, Saddle angle & Gonial angle. 6. Increased Ramus height and Body length. 7.Decreased sum of posterior angles. 8.Decreased lower anterior facial height. 9.Increased jarabacks ratio. 10. Convergent upper and lower jaw bases. 11. Horizontal growth pattern or forward rotation or anticlock wise rotation of the of the lower jaw 12. According to sassouni ….. 15 Dr Ravikanth Lakkakula
  16. 16. I) POSITIONAL DEVIATIONS 1. The four planes of the face (Supraorbitale,(tangent to sella and parellel with anterior cranial base) palatal, occlusal and mandibular plane) are horizontal and nearly parallel to each other. 2. The midface is usually retrusive, creating a concave profile. 3. The posterior vertical chain of muscles (Masseter, Internal Pterygoid, Temporal) are strong and attached anteriorly on the mandible and stretches in nearly straight line vertically. The molars are directly under the impact of masticatory forces on the posterior vertical chain of muscles, results in greater depressive action is transmitted to the dentition. 16 Dr Ravikanth Lakkakula
  17. 17. II) DIMENSIONAL DEVIATIONS 1. The Total posterior Facial height (Sella to Gonion) is nearly equal to Anterior Facial Height . 2. The lower face height (ANS-Me) is equal or smaller than upper face height (SOr - ANS). 3. A lack of ante gonial notch in the mandible leads to what is some times called as a ‘rocking lower border of the mandible. 17 Dr Ravikanth Lakkakula
  18. 18. 4. The facial breadth tends to equal to total face height, giving a square face appearance in the frontal view. 5. The mandibular symphysis is short vertically and broad antero – posteriorly. 6. The distance between supra mentale (point B) and pogonion is large, creating a ‘chin button’. 7. Skull is usually round or brachycephalic and europrosopic face. 8. Nasion is deep-seated posterior to both frontal and nasal bones. 18 Dr Ravikanth Lakkakula
  19. 19. Forward Rotator Backward Rotator 1. Inclination of condylar head Curves forward and back. Straight and slopes up 2.Curvature of mandibular canal Curved straight Bjorks Seven Structural Guidelines 19 Dr Ravikanth Lakkakula
  20. 20. 3.Shape of mandibular lower border Curved downward Notched 4.Inclination of symphysis (anterior aspect just below B point) Slopes backward Slopes forward 20 Dr Ravikanth Lakkakula
  21. 21. 5.Interincisal angle Vertical or obtuse Acute 6.Interpremolar or intermolar angle Vertical or obtuse Acute 21 Dr Ravikanth Lakkakula
  22. 22. 7.Anterior lower facial height Short Tall 22 Dr Ravikanth Lakkakula
  23. 23. Management of low angle case 23 Dr Ravikanth Lakkakula
  24. 24. Treatment modalities include 1)Intrusion of upper and lower anterior teeth. 2) Extrusion of posterior teeth. 3)combination of intrusion of anteriors and extrusion of posteriors. 4) Proclination of incisors. 5) Adult surgery. 24 Dr Ravikanth Lakkakula
  25. 25. Soft tissue considerations a) Interlabial gap 2 to 3 mm is normal. If interlabial gap is excessive, molar extrusion should be avoided. b) Smile line In case of gummy smile , intrusion of maxillary incisors should be done. c)Lip length In cases of short upper lip, intrusion should be carried out. 25 Dr Ravikanth Lakkakula
  26. 26. Inter occlusal space The average inter occlusal space is 2-4mm in premolar region. Increase interocclusal space is an indication that molars are not fully erupted. so treated by extrusion of posterior teeth. The presence of normal inter occlusal space is indication of intrusion of anterior teeth rather than extrusion of molars. Reduction of normal inter occlusal space by extrusion of molars can results in fatigue of muscles of mastication which get stretched and predisposed to relapse. 26 Dr Ravikanth Lakkakula
  27. 27. Dental considerations. Incisor intrusion is ideal to treat deep bite in cases of supraeruption and gummy smile. It maintains the vertical dimension. Upto 4 mm of incisor intrusion can be achieved. Skeletal considerations In case of decreased lower anterior face height , extrusion of molars is acceptable but it should be attempted only in growing children. If the same is attempted in adults, the stability of the result will be questionable. In patients with increased face height, intrusion of anteriors should be considered 27 Dr Ravikanth Lakkakula
  28. 28. Type of growth pattern Growing patient Non growing patient Average grower Molar extrusion/incisor intrusion True incisor intrusion Horizontal grower Molar extrusion Mandibular advancement and Molar extrusion Vertical grower True incisor intrusion True incisor intrusion 28 Dr Ravikanth Lakkakula
  29. 29. Anterior bite plane It is suggested by “callway and thompson”, who advocated stimulating the eruption of the posterior teeth as a way of filling in the bite i.e , opening the bite anteriorly with a bite plate , then allowing the posterior teeth to erupt into occlusion , through the reduction of excessive freeway space. A bite plate also used as an adjunct to fixed appliance treatment especially in situation in which the patient otherwise would have heavy contact on brackets bonded to the mandibular teeth. 29Removable appliances Dr Ravikanth Lakkakula
  30. 30. With this appliance in the mouth during the mandibular closing movement, the mandibular incisors come in contact with the acrylic platform, which causes a disocclusion of the posterior teeth. The disocclusion leaves the molars free to erupt.The disocclusion of the bite accelerates the passive eruption of the posterior teeth, which stops when one or more opposing teeth come in contact. It is advisable not to disocclude the posterior teeth more than 2 mm. If bite opening in the anterior region is not sufficient, the acrylic platform can be augmented in small increments several times during the treatment. 30 Dr Ravikanth Lakkakula
  31. 31. In recent years either “ Bite Turbos ” bonded to the lingual surfaces of the maxillary anterior teeth or buildups of bonding material on occlusal surfaces of the molars or premolars bilaterally have been used to clear the occlusion. It should be remembered that increasing the vertical dimension during class ΙΙ treatment , however , will tend to mask positive anterioposterior changes in mandibular growth. As a general rule each mm of increase in lower anterior facial height will camouflage or mask a millimeter of increase in mandibular length by autorotation the chin downward and backward. 31 Dr Ravikanth Lakkakula
  32. 32. The patient wears this appliance almost 24 hours a day. The use of bite plates, at the time of attaining the desired overbite, should not be Suddenly stopped, the bite plate itself should be used as a retainer and its discontinuance should be gradual. 32 Dr Ravikanth Lakkakula
  33. 33. 33 1) Myofunctional Appliance Activator Bionator Twin block Frankel II appliance 2) Extraoral Orthopaedic appliances Cervical headgear 3) Fixed Functional Appliances Herbst appliance Jasper jumper Forsus Fatigue resistance device Twin force bite corrector Growth Modulation Methods Dr Ravikanth Lakkakula
  34. 34. 34 TIMING OF TREATMENT It is not logical to favour early treatment at age 8 – 10 years only for growth reasons because there is plenty of mandibular growth still available at age 11- 13 years. Growth studies give only average values for the amount, direction and timing of growth but there is wide variation among individuals. It is recommended to start treatment in the late Mixed dentition at dental age 11-12 years with entire correction being accomplished in one treatment. Class II molar relation tendency is easier to intercept prior to maxillary second molar eruption. Early correction of skeletal deficiency , with an orthopedic appliance , greatly reduce the time required for second stage treatment. Von Bremen and Pancherz investigated the efficiency of early versus late Class II div I treatment in a group of 204 patients. They concluded that the treatment of Class II div1 malocclusion is more efficient in permanent dentition than it is in the mixed dentition. Dr Ravikanth Lakkakula
  35. 35. 35 Bondevik reported greater treatment success with increasing age of the patient. The mean age in the group with satisfactory treatment result was 11.95 years, while the mean age in the unsatisfactory group was 10. 87 years. This suggests that the treatment results were better with late treated cases. In 2004, Tulloch and co-workers published the outcomes from an important 10 year study on 137 patients in a prospective randomized controlled trial. Their findings suggested that early and late treatment started before adolescence in the mixed dentition might be no more clinically effective than the treatment started during adolescence in the early permanent dentition. They also noted that early treatment appeared to be less efficient because it produced no reduction in the average time with fixed appliance. Dr Ravikanth Lakkakula
  36. 36. 36 In 2005, Hsich and coworkers investigated 512 consecutive patients and found that it was inefficient to start treatment in the mixed dentition with Early treatment objectives or to start treatment before the age of 10 years in males and 10. 5 years in females. The disadvantages of early treatment included prolonged treatment time, increased patient/parent burn out and a worse incidence of compromised treatment outcomes. In spite of these disadvantages, in few individuals an early start of treatment can Be considered such as social or psychological reason or risk of enamel damage. Dr Ravikanth Lakkakula
  37. 37. Activator Dentoalveolar deep overbite : When the deep overbite is due to infra occlusion of the posterior teeth, the interocclusal clearance is large and hence the construction bite is made high or moderate depending on the size of the freeway space. When the deep overbite is due to supraocclusion of the incisors, the interocclusal distance is small, high construction bite should not be used. Intrusion of the incisors is possible to only a limited extent when an is being used. 37 Dr Ravikanth Lakkakula
  38. 38. In a skeletal deep overbite : The construction bite should be such that it is 5-6mm,more than the freeway space. Intrusion is achieved by loading the incisal edges of these teeth. If they are ground properly they become the only loaded or contacting surfaces, with no other than contact between incisors and acrylic, even in alveolar area. If simultaneous use of active labial bow is indicated , the contact between the bow wire and incisors is on the incisal third. Extrusion of molars can be facilitated by loading the lingual surfaces of these teeth above the area of greatest convexity in the maxilla or below this area in mandible. 38 Dr Ravikanth Lakkakula
  39. 39. Bionator The Main objective is to establish a muscular equilibrium between the forces of the tongue and outer neuromuscular envelope. Balter’s terminology refers to stimulation of eruption as unloading or promotion of growth and prevention of eruption as loading or inhibition of growth. Most bionators that are used in today are designed not only to posture the mandible into more forward position but also to facilitate the eruption of the posterior teeth in patients with decreased vertical dimension , so called california bionator. 39 Dr Ravikanth Lakkakula
  40. 40. Trimming of acrylic tooth beds and elimination of the influence of tongue and cheeks allow teeth to erupt until they reach the articular plane. The difficulty in managing the classic bionator is the alternative loading and unloading of certain areas. On one visit acrylic is added to load a specific tooth. On the next visit it may be ground away in the same area. Especially in the deepbite adequate space is necessary to allow for full eruption of the teeth. 40 Dr Ravikanth Lakkakula
  41. 41. To allow extrusion of the posterior teeth , some acrylic is always left interdentally at the level of occlusal plane, forming so called tooth bed. The upper and lower molar regions should be trimmed first. Then lower premolars are trimmed while the molars are loaded. Finally upper premolars are stimulated while lower premolars and molars are loaded. Care must be taken to ensure that lingual acrylic surfaces do not interfere with eruption. 41 Dr Ravikanth Lakkakula
  42. 42. Control of incisors The bionator is constructed typically so that the mandibular incisors are covered with an acrylic incisal cap. The covering the lower incisors presumbly prevents the vertical eruption of these teeth and stabilizes the bionator in the mouth. The thickness of the acrylic cap can be reduced for increased patient acceptance. The maxillary incisors are restricted anterioposteriorly by the upper labial and lingual wires. The incisal edges of the maxillary incisors usually contact the top of the lower incisal cap , preventing vertical eruption of incisors. 42 Dr Ravikanth Lakkakula
  43. 43. Frankel 2 regulator Frankel 2 is indicated in the mixed dentition with short lower anterior facial height ,deep overbite and abnormal activity, leading to bite opening and facial esthetics. Frankel appliance has buccal sheilds and lip pads that the prevent the deforming muscle action in the dento alveolar region both during deglutation and at rest. Upper lingual wire originates from the buccal sheilds and runs between the maxillary canine and the first premolar. 43 Dr Ravikanth Lakkakula
  44. 44. Lower lingual portion prevents the maxillary incisors from tipping lingually after they were protruded by fixed or removable appliances. Lingual wire is most important in cases with a deficient anterior lower facial height particularly when forward rotational pattern. The lingual shield lies lingually below the gingival margin of the mandibular teeth and extends distally to the roots of the lower second premolar. Its position is secured by two wires connecting it with the buccal shields of either side. Lingual shied is an important part of the exercise device which is used to overcome the poor postural performance of the muscles suspending the mandible. 44 Dr Ravikanth Lakkakula
  45. 45. The bite opening accomplished by when the upper and lower lingual wires are bent against the cinguli of maxillary and mandibular incisors. Thus an overeruption of the incisors can be prevented and the posterior teeth are allowed to erupt spontaneously. Levelling the curve of spee is mainly due to the buccal shields which prevent the adjacent soft tissues of the cheek from lodging interocclusally. 45 Dr Ravikanth Lakkakula
  46. 46. It is act as a exercise device whenever the mandible tends to slide back to its original position a pressure sentation on the lingual aspect the alveolar process is provoked. This sensory input may activate the propioreceptors in the gingiva and underlying periosteum and as a result of feedback , stimulate the protractors to eliminate this disturbing signal. however this mode of action can be expected to be established if an anterior displacement of the mandible carried out step by step. 46 Dr Ravikanth Lakkakula
  47. 47. Twin block Aim is increase the vertical dimension and improve profile by increasing the lower facial height by correcting the incisors to edge to edge relation while adjusting the height of upper bite block in the molar region to encourage molar eruption. Deep bite reduced by overcorrecting to an edge to edge incisor relationship with an interincisal clearance of 2mm in protrusive bite. In recording the construction bite the clinician normally leaves 5mm of clearance in first premolar region which is equivalent to 2mm of clearance distally in the molar region. Then trim the upper twin block Occulsodistally to encourage the eruption of lower molars. The inclined plane is maintain intact through out treatment to preserve the active mechanism for functional correction..the occlusion is cleared over the lower molars by 1 to 2mm only. 47 Dr Ravikanth Lakkakula
  48. 48. At the end of the active phase incisors and molars are in correct occlusion while open bite present in premolar region. The final adjustment is to trim the lower block slightly to reduce the open bite in premolar region. Eruption of lower molars occurs more quickly if separating elastics are placed in inter dental contacts with adjacent teeth at the start of the treatment or apply vertical elastics from upper appliance to hook on the lower molars. 48 Dr Ravikanth Lakkakula
  49. 49. 2.Extraoral Orthopaedic Appliance. Cervical Headgear The cervical (low- pull or kloehn) headgear is used most frequently in patients with decreased lower anterior facial height. The inner bow anchored to tubes that are placed on the buccal surfaces of bands that are attached to the upper first molars. 49 Dr Ravikanth Lakkakula
  50. 50. The outer bow is connected to strap that extends to the cervical regions and is anchored against the dorsal aspect of the neck. Usually the outer bow of the face bow lies above the plane of occlusion(15 to 20 degrees), so that force is directed through the center of resistance to prevent distal tipping of the molars during treatment. Numerous clinical studies showed that the forward movement of the maxilla inhibited through the use of this type of appliances. It is also increase the vertical dimension through extrusion of molars. 50 Dr Ravikanth Lakkakula
  51. 51. Herbst appliance The herbst appliance can be compared with a an artificial joint between the maxilla and mandible. The bilateral telescopic mechanism maintains the protracted position of the mandible even during function. It consist of a tube , plunger , two pivots and two locking screws that prevents the telescopic elements from slipping past pivots. The pivot for the tube usually is soldered to the maxillary first molar band and the pivot for the plunger is attached to the mandibular first premolar band. 51Fixed Functional Appliances Dr Ravikanth Lakkakula
  52. 52. In class 2 malocclusions with deep bite may be reduced significantly with herbst therapy , this results are mainly from eruption of lower molars and intrusion of lower incisors. One of the major advantage of the herbst appliance is the relative speed at which treatment effects are achieved . The disadvantage is rigidity of the bite jumping mechanism , although every attempt is made to allow freedom of movement by having the orthodontist enlarge the attachment holes of the tube and plunger to the axles(complex laboratory work ),the bite jumping mechanism can restrict lateral movement of the mandible. 52 Dr Ravikanth Lakkakula
  53. 53. Jasper jumper Jasper jumper modular system can be used with most types of fixed appliances. The system is composed of force module and anchor units. The force module , analogue to the tube and plunger parts of the herbst bite jumping mechanism, is flexible . The force module is constructed of a stainless steel coil or spring that is attached to the both ends to stainless steel Endcaps, in which holes have been drilled in the flanges to accomdate the anchoring unit. This module is surrounded by an opaque polyurethane covering for hygiene and comfort. The module are available in seven lengths , ranging from 26mm to 38 mm in 2mm increments. They are designed for use on either side of the dental arch. 53 Dr Ravikanth Lakkakula
  54. 54. The force module is attached posteriorly to maxillary arch by a ball pin that is placed through the face bow tube on the maxillary first molar band. The ball pin is anchored in position by having the clinician place a return bend in the ball pin at its mesial end. Anteriorly the module is anchored to the mandibular arch wire. Bayonet bends are placed distal to the mandibular canines and small lexan beads are slipped over the arch wire to provide an anterior stop. 54 Dr Ravikanth Lakkakula
  55. 55. When the force module is straight , it remains passive. As the teeth come into occlusion , the spring of the force module is curved axially as the muscles of mastication elevate the mandible, producing forces from one ounces to sixteen ounces. This kinetic energy then is captured when the force module is curved , and the force is converted to potential energy to be used for a variety of clinical effects. 55 Dr Ravikanth Lakkakula
  56. 56. Forsus fatigue resistance device The Forsus Fatigue Resistant Device (FRD) is an alternative interarch appliance for treating Class II malocclusion. A mandibular push rod attaches directly to the lower arch wire distal to the canines, and a telescoping spring attaches to the headgear tube with an L-pin or EZ module. Forces are unloaded when the patient’s jaw opens, resulting in intrusive rather than extrusive force vectors. The Forsus FRD exerts a continuous force with more elasticity and flexibility than the Herbst, permitting a greater range of mandibular opening and lateral movements during speech, chewing, and swallowing. Because muscular forces are distributed over a larger periodontal area, there is less inhibition of the jaw elevator muscles by the periodontal mechanoreceptors, allowing better stabilization of the mandible. 56 Dr Ravikanth Lakkakula
  57. 57. Modified the .019" × .025" stainless steel mandibular arch wire by incorporating a small, circular occlusal loop on each side, distal to the canines. The mesial end of the mandibular push rod is placed over the arch wire just distal to this occlusal loop and crimped slightly to secure it . The point of force application is thus shifted from the canine brackets to the rigid mandibular arch wire, distributing the forces over a wider surface area. In cases where the inter bracket span is too narrow to permit placement of the mandibular push rod distal to the occlusal loop, the mesial end of the push rod can be inserted directly into the loop and crimped in place. 57 Dr Ravikanth Lakkakula
  58. 58. Twin force bite corrector The TFBC is a fixed, push-type intermaxillary functional appliance with ball-and-socket joint fasteners that allow a wide range of motion and lateral jaw movement .The two plunger/tube telescopic assemblies on each side contain nickel titanium coil springs that deliver a constant force. Measuring several appliances with a force gauge demonstrated an average full-compression force of approximately 210g. 58 Dr Ravikanth Lakkakula
  59. 59. Titanium components provide a secure lock onto the arch wire, allowing every placement and removal of this single-piece appliance to be done chair side in just seconds Time and cost savings , No waiting for the lab to fabricate the appliance No patient cooperation required . Maximum results with minimal patient cooperation, Comfortable . Increased lateral excursion not found with most distal zing appliances Versatile, Suitable for both extraction and non-extraction cases . The appliance is attached to the maxillary and mandibular arch wires by hex nuts fastened mesial to the maxillary first molars and distal to the mandibular canines. At full compression, the TFBC postures the patient's mandible forward into an edge-to-edge occlusion. 59 Dr Ravikanth Lakkakula
  60. 60. Magnetic Activator Device (MAD), was introduced by Darendeliler and Joho. The design of the MAD II developed progressively using smaller magnets(samarium-cobalt and neodymium-iron-boron) and reduced force levels. The magnet shape and dimensions changed from a rectangular bar, to a triangular prism and then to a cylindrical form. Darendeliler and Joho commented that the skeletal versus dental response depended on the intensity of the magnetic force. The use of attracting magnetic forces, ranging from 150 to 600 grams per side, revealed that a force of more than 500 grams appeared to produce unwanted or exaggerated dental movements. Magnets-MAD II Appliance 60 Dr Ravikanth Lakkakula
  61. 61. Forces below 200 grams were insufficient to obtain protrusion of the mandible. A force of 300 grams per side was found to be appropriate in patients age 7 to 12 for correcting Class II malocclusion by growth modification with only minimal tooth movement. The MAD can be worn full time, except during meals since phonation and deglutination are not as limited. It has also been suggested by Darendeliler that bonded magnetic appliances could be used as fixed functional appliances. The advantages of magnets over traditional force delivery systems are: frictionless mechanics, predictable force levels and force direction when the magnets are in attractive configuration, no force decay over time, and less patient cooperation. 61 Dr Ravikanth Lakkakula
  62. 62. 62 i) Segmental arch mechanics Burstone intrusion arch Three piece intrusion arch Rickets utility arch ii) Continuous arch mechanics Anchorage bends Bite opening curves Connecticut Intrusion arch iii) Loop Mechanics K - sir arch Asymmetric T- loop iv) Extrusion of posterior teeth mechanisms Tip back mechanism Base arch mechanism 0.016 distal extension parallel eruption of buccal segment Fixed Mechanotherapy Dr Ravikanth Lakkakula
  63. 63. 63 Fixed orthodontic appliances can be used to intrude the incisors or extrude the molars. They can also produce mild skeletal effects (increases the lower anterior facial height). Appliances used for deep bite correction are generically termed intrusion arches and variations include base arches, utility arches, Connecticut arch and Reverse curve of Spee wires etc..,. Incisor overbite correction can be accomplished by two methods. One method is by the extrusion of posterior teeth, which increases the lower face height by mandibular rotation. The second method is by the intrusion of the upper or lower incisor teeth, with little or no mandibular rotation. Dr Ravikanth Lakkakula
  64. 64. Treatment modalities in growing and non growing patients. 1. Growing patients. Intrude anteriors. Erupt posteriors. Combination of posterior eruption and anterior intrusion. 2. Non growing patients (little or no growth expected) Orthognathic surgery Intrusion of anteriors (posterior extrusion invariably relapses) Whatever the treatment modality the management of deep bite is by intrusion of anteriors, extrusion of posteriors or combination of the both 64 Dr Ravikanth Lakkakula
  65. 65. Intrusion of anteriors Intrusive mechanics is considered in the following situations . Deep bite with large inter labial gap(In a relaxed mandibular position, an individual has normal of 2 to 4 mm) , intrusion is the ideal choice. Extrusion of posteriors may deteriorate the esthetics and further increase the inter labial gap. In a clinical situation, if incisor-stomion distance is large, ( the distance between the incisal edge of the maxillary central incisor to the lower most border of the upper lip is an average of 2 to 4 mm) which is often associated with a high smile line or "gummy smile", the best method of treating a deep Overbite may be by intrusion of the upper incisors. 65 Dr Ravikanth Lakkakula
  66. 66. In a Class II, division 1 type of malocclusion with large vertical facial height, extrusion of posterior teeth may cause serious functional, esthetic, And stability problems. Extrusion of molar furthers causes the downward and backward rotation of the mandible worsening the condition. In those Cases the intrusion of anteriors is the treatment option. Intrusion mechanics are considered if there is inadequate or normal freeway space. Encroachment of this space by extrusion of posterior teeth is determinant and bound to relapse. It results in fatigue of the muscles of Mastication which get stretched and predispose to relapse. It also strains the TMJ. 66 Dr Ravikanth Lakkakula
  67. 67. Teeth Force value(grams) Maxillary central incisor 12-15 Maxillary lateral incisor 8-10 Maxillary canine 25 Mandibular central incisor 8-10 Mandibular lateral incisor 8-10 Mandibular canine 25 Maxillary four incisors 35-50 Mandibular four incisors 30-40 FORCE VALUES FOR INTRUSION OF ANTERIOR TEETH 67 Dr Ravikanth Lakkakula
  68. 68. Absolute intrusion . Relative intrusion - Achieved by preventing eruption of incisors while growth provides vertical space into which posteriors erupt. Extrusion of posterior teeth causes the mandible to rotate downward and back in the absence of growth. 68 Dr Ravikanth Lakkakula
  69. 69. Levelling by Intrusion . This requires a mechanical arrangement other than a continuous arch wire attached to each tooth (Proffit, 2000). The key to successful intrusion is light continuous force directed towards the apex. It is necessary to avoid pitting intrusion of one tooth against extrusion of its neighbour, since in that circumstance, extrusion will dominate. This can be accomplished in two ways: 1) with continuous arch wires that bypass the premolar (and frequently the canine teeth) 2) with segmented base arch wires (so that there is no connection along the arch between the anterior and posterior segments) and an auxiliary depressing arch. 69 Dr Ravikanth Lakkakula
  70. 70. Continuous Arch Mechanics Segmental Arch Mechanics Reverse curve of spee in lower Exaggerated Curve in Upper Intrusion Arches Extrusion of Premolars and molars Intrusion of Incisors only Increase lower anterior facial Height by rotating the mandible open. Mandible may rotate closed or be prevented from rotating open. Flare Incisors Labially. Intrusive force against the incisors is applied anterior to the centre of resistance causes incisors to tip forwards as they intrude . No Flaring of Incisors. The point of force application may be altered by tying it more distally. The force is then closer to the labial segment’s centre of resistance – this prevents incisor proclination without straining posterior anchorage 70 Dr Ravikanth Lakkakula
  71. 71. 71 Dr Ravikanth Lakkakula
  72. 72. Extrusion of posterior teeth. In deep bite with redundant upper and / or lower lips , or no Inter labial gap, posterior extrusive mechanics may be desirable (if other considerations permit). If a patient with deep overbite exhibits normal incision - stomion distance, the choice of correction of deep bite by an intrusion of maxillary incisors is often contraindicated since it will give the Patient an edentulous appearance. Extrusion of posteriors is the treatment option . In patients having excessive overbite with Class II, division 2 type of skeletal malocclusion, an extrusion of the posterior teeth met be the treatment of choice ( if other considerations permit). Extrusion mechanics are considered if there is adequate inter occlusal space. 72 Dr Ravikanth Lakkakula
  73. 73. 73 correction of deepbite by this method is often indicated in patients having steep occlusal plane angle . The buccal segments are negatively rotated as they are erupted, because the movement of force is coming from cantilever type appliances. These are generally used in the lower jaw to level the deep curve of spee by eruption of the posterior teeth. Deep overbite correction by erupting the posterior teeth occurs fairly rapidly, the eruption of posterior teeth so much faster than intrusion of teeth .The choice of which eruptive mechanism to use depends upon the choice of center of rotation. The posterior teeth usually be leveled about several center of rotation , depends on the amount of required arch length. The four types of extrusion mechanisms are 1.Tip back mechanism. 2.Base arch mechanism. 3. 0.016 inch distal extension. 4. Parallel eruption of buccal segment. Dr Ravikanth Lakkakula
  74. 74. An increase in proclination of upper and lower anterior incisors can effectively decrease the deep bite. Flaring incisors tends to decrease overbite secondary to the rotational movement of the incisor crowns. For mild to moderate corrections , this approach may be very effective. It is best indicated in lingually tipped incisors , such as class 2 div 2 malocclusions or class 3 malocclusion then can withstand flaring of the upper and lower incisors. 74 Proclination of incisors Dr Ravikanth Lakkakula
  75. 75. A Intrusive arch normally consists of an 0.018 x 0.025 inch ss by with a two and half turn helix or alternatively .019 x .025 TMA without helix, 2 mm mesial to the auxiliary tube. Curvature is placed in the intrusive arch, so that the incisal portion lies gingival to the central incisor. When the arch is tied to the level of the incisors, an intrusive force(10- 15grams) is developed. In order that the arch does not increase its length during the activation, a gentle curvature should be placed with the amount of curvature increasing as one approaches the helix. In this way the activated arch wire will appear relatively straight, and as it works out during intrusion, arch length will decrease and no anterior flaring is produced. Burstone intrusion arch 75 Dr Ravikanth Lakkakula
  76. 76. Three piece intrusion arch It is introduced by burstone , shroff,lindauer and leiss in 1995 It consist of following parts : 1)The posterior anchorage unit 2) anterior segment with posterior extention 3) intrusion cantilevers 4) elastic chain. The anterior segment(019x025 ss) was bent gingivally distal to the laterals , then bent horizontally , creating a step of approximately 3mm.the distal part is extended posteriorly to distal end of the canine bracket, ending in the form of a hook. The anterior part was fabricated heavy stainless steel wire to prevent side effects created by bending of wire during force application. The posterior segments are consolidated using 019 x 025 ss wire from canine to second molar. 76 Dr Ravikanth Lakkakula
  77. 77. The anterior segment allowed further displacement of the intrusive forces, which was desirable in case of flared incisors. The intrusion cantilevers are fabricated from 017 x 025 inch TMA wire. The wire was first bend gingivally mesial to the molar tube then helix formed. On the mesial end a hook was formed for placement of intrusive forces on anterior teeth. It is activated by placing a bend mesial to the molar tube then cinch back. A E - chain was attached to produce simultaneous intrusion and retraction. E chain was extended from molar hook to posterior hook of the anterior segment. A 150 grams force per canine used with e chain for separate canine retraction. A 200 grams force used for incisors retraction after canine retration. 77 Dr Ravikanth Lakkakula
  78. 78. Fabricated from blue elgiloy either .016" x .016 " or .016 " x .022 “ for 018 slot and .019 " x .019 “ for .022 slot . Generally rectangular wires are preferred than round wires to control torque and to prevent unwanted tipping of incisors. Other types of arch wires also used(TMA). It consist of molar segment extends into a tube or may be bent gingivally , if the utility arch is to be tied back. Posterior vertical segment is formed by making a 90 degrees bend.This posterior step is 3-4mm in mandible. Ricketts utility arch 78 Dr Ravikanth Lakkakula
  79. 79. Vestibular segment is formed by placing a right angle bend at inferior portion of the posterior vertical segment. Anterior vertical segments(90 degree bend) should be about 4-5mm in length when the utility arch is used in the mandible. Its depths is differs from patient to patient. In contrast to the passive utility arch that fits flush against the auxillary of the molar tube , there is atleast a 5mm space between the anterior border of the auxiliary tube and posterior vertical segment of the utility arch. 79 Dr Ravikanth Lakkakula
  80. 80. Intrusive force are produced by using loop forming pliers to place an occlusally directed gable bend in posterior aspect of the vestibular segment. After activation, the vestibular segments and anterior and posterior vertical segments, which serve as long lever arm from the molars to the incisors , deliver a light continuous force. The utility arch produce 60-100 grams of force on the mandibular incisors , a force level considered ideal for mandibular incisor intrusion. 80 Dr Ravikanth Lakkakula
  81. 81. Anchor bends are given in the .016 inch Australian stainless steel arch wire 2mm mesial to the molar tube , so that the anterior part of the arch wire lies gingival to the bracket slot . Thus when these arch wires are pulled occlusally and engaged into the brackets, a gingivally directed intrusive force is exerted on the incisors which reduces the deep bite. When intrusion of anterior teeth is the goal, light forces should be used. Heavier forces are more likely to create a greater tendency for posterior teeth to erupt as a result of the equal and opposite extrusive force at the molar.The reactionary extrusive force on molars is prevented by natural Interdigitating occlusion or in extreme cases by giving a posterior bite plane of minimum thickness. Anchorage bends 81 Dr Ravikanth Lakkakula
  82. 82. Intermaxillary elastics Extrusion of molars might be fortified by means of elastics, which attempt to overerupt the molars in both the upper and lower jaws. Use of anchorage bend in the upper jaw as well as in the lower jaw in combination with Class II elastics may cause overeruption of the lower molars and may help to correct a dental deep bite.One of the draw backs of the class II elastics is that it results in extrusion of the upper incisors, in an attempt to over erupt lower molars. 82 Dr Ravikanth Lakkakula
  83. 83. Bite opening curves one millimeter of upper or lower molar extrusion effectively reduces the incisor overlap by 1.5 – 2.5mm and 3 mm increases in lower anterior facial height. A very common method is use of reverse curve of spee in lower and exaggerated curve of spee wires in upper arch and progressively increase in step bends in arch wires. 83 Dr Ravikanth Lakkakula
  84. 84. Reverse curve of spee correct the deep bite primarly by extrusion of posterior teeth , along with intrusion and flaring of incisors. Both extrusion and flaring may be unstable movements due to their effect on the facial neuromuscular balance. Reverse curve of spee wires also alter their the axial inclination of posterior teeth, which may also contribute to relapse. 84 Dr Ravikanth Lakkakula
  85. 85. Placement of step up (Maxillary incisors) and step down (Mandibular incisors) bends also commonly used to correct deepbite. This method of correction combines extrusion of the adjacent cuspids and posterior teeth and perhaps some intrusion of incisors described by burstone and koenig. The step bends creates two movements in same direction causing changes in the axial inclination of teeth and cant of the occlusal planes. 85 Dr Ravikanth Lakkakula
  86. 86. Step bends are indicated when there is a step between the anterior and posterior occlusal planes, in cases with moderate to minimal incisors display, and class ǀ malocclusions. The primary drawback of this approach is the resultant indiscriminate posterior extrusion versus anterior intrusion and the change in cant of the occlusal plane towards a deep bite. 86 Dr Ravikanth Lakkakula
  87. 87. The CTA is fabricated from a nickel titanium alloy to provide the advantages of shape memory, springback, and light, continuous force distribution. It incorporates the characteristics of the utility arch as well as those of the conventional intrusion arch. The CTA is preformed with the appropriate bends necessary for easy insertion and use. Two wire sizes are available: .016" x .022" and .017" x .025". The maxillary and mandibular versions have anterior dimensions of 34mm and 28mm, respectively. Connecticut intrusion arch 87 Dr Ravikanth Lakkakula
  88. 88. The CTA's basic mechanism for force delivery is a V-bend calibrated to deliver approximately 40-60g of force. Upon insertion, the V-bend lies just anterior to the molar brackets. When the arch is activated, a simple force system results , consisting of a vertical force in the anterior region and a moment in the posterior region. 88 Dr Ravikanth Lakkakula
  89. 89. Simultaneous intrusion and retraction of the six anterior by using non-frictional loop mechanics, which was developed by Dr. Varun Kalra, based on space closure mechanics advocated by Dr. C. J. Burstone. A continuous 0.19" x 0.25" TMA archwire with closed7mm x 2mm U-loops at extraction sites . 90˚ V-bend is placed in the archwire at the level of each U-loop by placing centered V – bends which create two equal and opposite moments. K- SIR arch wire 89 Dr Ravikanth Lakkakula
  90. 90. A V-bend located posterior to the center of inter bracket distance to augments molar anchorage during intrusion of anterior teeth. And 20 ˚ Anti-rotation bends are placed to prevent molar rotations. 0.019" x 0.025" TMA provides sufficient strength to resist distortion, but enough stiffness to generate required moments. At the same time TMA has low forces, low load deflection rate and high range of activation. 90 Dr Ravikanth Lakkakula
  91. 91. A system made of .019” x .025” TMA (.022” brackets) and .017” x .025” TMA (.018”brackets) has been proven effective in achieving simultaneous intrusion and retraction of incisors. This asymmetric “T” loop archwire has a loop that is placed distal to the upper lateral incisors. The loop can be activated intraorally for the multiple adjustments like, intrusion and retraction of incisors, or to increase torque during retraction. A small rounded bird beak plier is used to bend the loop into a preformed TMA archwire. Shape memory of the wire and the loop configuration make this a multipurpose system which can be incorporated into a continuous archwire. The vertical portion of the loop should be 5mm, the anterior loop 2mm, and the posterior loop 5mm. The archwire has an exaggerated reverse Curve of Spee and strong distal molar rotation. Bend the loop inwards to prevent irritation to the cheek. Asymmetric T - Loop 91 Dr Ravikanth Lakkakula
  92. 92. 92 Indications 1. In growing patients with a forward growth rotation. 2. For deep curve of spee in lower arch. 3. For a deep overbite. 4. For slight arch length inadequacy(1-2mm per side). 5. For a steepened natural plane of occlusion. The tip back mechanism consist of 1. 0.036 inch lingual arch. 2. 0.018 x 0.025 inch anterior segment , which can sometimes be left long, distal to the cuspids. 3. Buccal stabilizing segments of 0.018 x 0.025 inch from(ideally) 7- 4. 4. 0.018 x 0.025 tip back spring. Tip back mechanism Dr Ravikanth Lakkakula
  93. 93. 93 The anterior portion of hook that can be placed over the anterior segment of wire. As it is activated (hooked over the anterior segment) , it produces a negative moment and an eruptive forces to the buccal segment (producing a C Rot at the distal aspect of the root of the second molar). In which , as the buccal segment becomes upright, some arch length gained anteriorly. Such a C Rot is found at the distal most aspect of the lower second molar, as the buccal segment is uprighted , one notices space appearing between the first premolar and canine . Dr Ravikanth Lakkakula
  94. 94. 94 The hook of the tip back mechanism , made so that it can slide freely in an anterioposterior direction , can be placed strategically over the 0.018 x 0.025 inch anterior segment. For example the anterior segment has normal inclination , the hook should be placed between the canine and lateral incisor (the approximate location of C Res of the anterior segment). If the lower anterior segment is slightly flared with the canines somewhat higher than the incisors , the depressive force should be placed distal to the C Res of the anterior segment. Dr Ravikanth Lakkakula
  95. 95. 95 With the correct use of tip back mechanism , one will notice that 1. The C Rot is placed distally , somewhere around the distal root of the second molar. 2. There is eruption and rotation of the buccal segments. 3. There is increased arch length distal to the canines(1 to 2 mm). 4. The second molar is often buried. 5. With the hook is placed distal to the C Res of the anterior segment , the roots of the lower anterior segment often come forward , which is good , if one is flattening the plane of occlusion. 6. There is no flaring of the anterior teeth, because the hook is made to slide freely along the anterior segment. The 3500 to 4500 gm of force is required to erupt and rotate the buccal segments optimally. Dr Ravikanth Lakkakula
  96. 96. 96 The base arch mechanism (sometimes also called an intrusive arch) can also used for extruding teeth in deepbite correction. The main difference between Tip back mechanism (distal most aspect of the lower second molar) and base arch (located close to the mesial root of lower first molar) is in the location of the center of rotation. Base arch mechanism Tip back mechanism Base Arch mechanism Dr Ravikanth Lakkakula
  97. 97. 97 The base arch mechanism is made from 0.018 x 0.025 inch ss wire with helicles, can also be fabricated from 0.017 x 0.025 inch TMA wire with no helicles or instead , a washer can be crimped on or a short piece of wire can be welded on for stop. when flaring of anterior teeth is not indicated , a ligature wire can be passed through the helicles to tie the base arch back. The force system is nearly identical to that of the tip back spring, expect the fact that there is no anterior hook free to slide anterioposteriorly ; with the base arch tied back securely. Dr Ravikanth Lakkakula
  98. 98. 98 With the correct use of base arch mechanism , one will notice that 1. Eruption and a negative rotation of the buccal segment (flattening of the plane of occlusion) 2. No increase in arch length. 3. That the roots of the buccal segment move forward. 4. That second molars appear to be buried (remember the negative moment) The force values used are based on the same optimal moment desired to erupt and rotate the buccal segment , i. e., 3500 to 4000 grams. Dr Ravikanth Lakkakula
  99. 99. 99 Sometimes , in order to level a deep curve of spee, both anterior and posterior segments need to be erupted and rotated. This eruption can be done with an appliance called 0.016 inch distal extension. In order to use this appliance, there should be 1. Good growth increments remaining, since the appliance is eruptive. 2. A significant second- order discrepancy between the canines and the incisors; Incisors should be higher than the canine. 3. Minimal arch length required (2-3mm per side). 4. A deep curve of spee. 5. Extraction of teeth, usually the first premolars. 0.016 distal extension Dr Ravikanth Lakkakula
  100. 100. 100 The appliance itself consist of 1. 0.018 x 0.025 inch base arch wire with helicles , but it may be made without them , especially if the newer , more flexible wires such TMA are used. 2. 0.016 inch distal extension – immediately mesial to the canine bracket a vertical loop is placed and immediately distal to the canine bracket a helix is placed. The distal extension can be adjusted to lie over the tie wings of the second premolar bracket , or can be hooked over the buccal segment wire. It can be opened the amount of the inadequacy that might be present(upto 2-3mm per side). Dr Ravikanth Lakkakula
  101. 101. 101 In order that this arch length inadequacy can be resolved by the canines being nuged back distally rather than by the incisors moving anteriorly , the base arch is tied back anteriorly at the midline and posteriorly through helicles. 3. 0.036 inch lingual arch. When the base arch is activated , the buccal segment will experience a negative moment tending to move its roots mesially and crowns distally. There is a corresponding depressive action of incisors. This depressive force is also mesial to the C Res of the anterior segment , so it produces distal root movement. Dr Ravikanth Lakkakula
  102. 102. 102 If one consider the effects of both appliances (base arch and 0.016 distal extension) , one can see that both alpha (anterior) and beta (posterior) moments are produced when each respective arm is activated. If both are given equal and opposite preactivated bends (alpha = beta ) both anterior and posterior segments will erupt and rotate (mesial root movement on the buccal segment and distal root movement on anterior segment). Higher alpha movement results in more eruption and rotation of the anterior segment; higher beta movements results in more eruption and rotation of the buccal segment. Dr Ravikanth Lakkakula
  103. 103. 103 Parallel eruption of the buccal segments is used in the upper jaw only. Using a cervical headgear with its long outer bow bent high (about 60 degrees), a negative moment is provided by bringing the outer bow down to the line of action of the headgear straps. Once engaged , the line of action of the force times the perpendicular distance away from the C Res of the upper jaw produces a positive movement. Both moments tend to cancel each other out and is left with a purely extrusive force to the buccal segments. Parallel eruption of the buccal segment Dr Ravikanth Lakkakula
  104. 104. Bilateral implants for en-masse intrusion of anteriors: The implants used are 1.3 mm in diameter and 8 mm in length. Bone contacts at insertion influences the primary stability of the implants. Increasing the diameter and length of the implant allows greater surface area contact between the bone and implant. It’s important to have a mechanical inter digitation between implants and cortical bone. Placement Site: For enmasse intrusion of the maxillary anterior teeth the most suitable site for the placement of implant selected is the alveolar bone between lateral incisor and canine bilaterally at the level of attached gingiva. Implants 104 Dr Ravikanth Lakkakula
  105. 105. Clinical set up 1.The maxillary dental anterior segment should extend from distal of canines on either side. A .021x .025 stainless steel arch is placed in all the three segments. In the anterior segment, hooks are placed between lateral incisor and canine bilaterally. This is followed by placement of mini implants which are loaded immediately. 2. A calibrated Dontrix gauge is used to measure the amount of intrusive force being applied. 45 gms of intrusive force is applied per side using a pre-stretched elastic chain i.e. a total of 90 gms of intrusive force is applied to the six anterior teeth. 3. A ligature wire lace back is tied extending from the maxillary molar hook to the tag incorporated distal to canine in the anterior segment. 105 Dr Ravikanth Lakkakula
  106. 106. Mid-implant for intrusion of maxillary incisors The implants used are 1.3 mm in diameter and 8 mm in length. A stainless steel archwire with utility design engaging four incisors and two molar, bypassing the canine and premolar is used made of 0.017x0.025 .Passive segmented posterior stabilizing unit (0.019x0.025) A closed coil spring or a E-chain can be used to deliver force of around 60- 70 grams. 106 Dr Ravikanth Lakkakula
  107. 107. The bite-plate effect of lingual brackets is well known Lingual brackets which are bonded on the palatal surface of the maxillary incisors act like a bonded anterior bite plate. This is relevant for all types of Lingual brackets, but more significantly for the 7 th Generation brackets (G7) which have a built-in bite plate in the anterior brackets. The bite plate represents a combination of different treatment strategies; it forces the mandible to open in backward rotation and allow the posterior teeth to extrude passively or actively, while simultaneously intruding the anterior teeth that are in contact with the plate. The bite-plate effect therefore has a significant clinical contribution for the treatment of deep bite cases, anterior or posterior X-bite and Class III tendency. Bite plate effect (lingual technique) 107 Dr Ravikanth Lakkakula
  108. 108. On the other hand there are some clinical situation in which the bite plate effect may have an adverse effect on the malocclusion, 1. Moderate class II cases with increased over jet, The bite-plate effect of the lingual brackets forces the mandible to open in backward rotation and as a result the over jet increases, Class II molar and canine relation may be aggravated. This point should be considered in the treatment plane and anchorage considerations. 2. Another risky situation is severe incisors proclination, when the lower incisors contact solely on the anterior brackets, tending to worsen the proclination . 3.More severely it is for periodontal patients when the bone level is reduced 4. The opposite extreme incisors inclination, when upper incisors are severely retroclined, is also risky when using anterior bite plate, since there is a tendency for the upper incisors to further retrocline due to occlusal forces applied palatal to the center of resistance. These adverse effects could be avoided by using temporarily posterior bite blocks. 108 Dr Ravikanth Lakkakula
  109. 109. It is made of plastic , designed by factory, are lingually placed 1-2 mm thick horizontal rectangular attachments, horizontal gingival beveled attachments or vertical rectangular attachments. Align’s default is the horizontal beveled attachment. Virtual Bite Ramps are never bonded to the teeth but act as a bite ramp when the patient has the aligners in place. By discluding the posterior teeth they prevent transient posterior intrusion. The amount of overjet will determine how thick you make the virtual bite ramps and whether you use horizontal or vertical orientation. Invisalign virtual bite ramps 109 Dr Ravikanth Lakkakula
  110. 110. If the patient has a large over jet, their lower incisors will not contact the Virtual Bite Ramps and you will not see the same bite opening effect. Mandibular advancement, class II elastics and upper Incisor position can all reduce over jet to allow contact with the virtual bite ramps. Vertically oriented bite ramps will follow the lingual slope of the upper incisors and will allow earlier contact with the bite ramps in those patients with large over jets. If we want to add this in the middle of the treatment by adding bite ramps to an aligner with Orthoarch mini mold anterior bite ramp with the Bite Plane Plier invented by Dr. Keith Hilliard. 110 Dr Ravikanth Lakkakula
  111. 111. In adult patient showing excessive deep overbite of 100 per cent or more, with accompanying; 1. High smile line. 2. Decreased Vertical facial height. 3 . Alveolar problems, the length of treatment may be very long. In this instance, the patient should be given a choice for a Orthognathic correction of the problem. In these patients, the treatment plan to correct the excessive overbite should be done in conjunction with an Oromaxillofacial surgeon. Surgical management 111 Dr Ravikanth Lakkakula
  112. 112. Maxillary surgery : The maxilla can be moved up quite successfully with Lefort I. Surgically repositioning of maxilla in superior direction can be done by complete maxillary osteotomy. The correction of deep bites resulting from vertical maxillary excess can be effectively corrected by this method. 112 Dr Ravikanth Lakkakula
  113. 113. Mandibular surgery : Patients with a short face (skeletal deep bite) problem are characterized by along Mandibular Ramus, square Gonial angle and short nose-chin distance. They are treated most predictably and successfully by mandibular Ramus surgery that allows the mandible to move downward only at the chin, increasing the mandibular plane angle. They are treated best by Saggital Split mandibular Ramus surgery to rotate the mandible slightly forward and down and the Gonial angle open up. The deep bites in the anterior mandibular alveolar region corrected by Sub Apical Osteotomy. 113 Dr Ravikanth Lakkakula
  114. 114. 114 Reduction of interincisal angle and establishment of guidance between the maxillary and mandibular incisors is important for the stability to be achieved in overbite correction. Muscular forces and growth , both have play in successful treatment of the class II division 2 malocclusion. In adult patients , vertical development of the buccal segments can not be expected and the stability of the bite opening is questionable. Hypodivergent facial types like class II division 2 with a deficiency in lower anterior facial height usually present problems in maintenance of permanent overbite correction. It has been reported that deep bite cases in which lower facial height is increased during treatment , exhibited less relapse than in cases in which little or no increase occurred during treatment. However, in patients where overbite correction was accomplished during their respective growth periods and those in whom vertical growth continued after retention seemed to maintain this correction many years out of retention. Stabilty and Retention Dr Ravikanth Lakkakula
  115. 115. Low angle case is a common form of malocclusion, that maybe addressed in many ways , including posterior extrusion , anterior intrusion and incisor flaring. The specific approach to bite opening should be selected based on each patients needs. Soft tissue, crown- gingival relations , occlusal plane and skeletofacial concerns are among the special considerations for treatment planning for low angle case corrections. Selecting the method and mechanism of the bite opening based on these considerations affords the opportunity to deliver goal oriented treatment. Understanding the biomechanics of the appliances chosen improves the clinicians ability to achieve the desired results. Conclusion 115 Dr Ravikanth Lakkakula