Introduction
Class II Division 2 malocclusion was first recorded in 1912 in German literature as “ Deckbiss”.1 Deep bite malocclusion is defined as a condition in which maxillary incisors excessively overlap the mandibular incisors vertically in centric occlusion.2
Deep overbite refers to coverage of mandibular incisors by maxillary incisors beyond 30-40%.3 Prevalence of deep bite is 21% worldwide.4 Several factors lead to development of deep bite which include incisor supraversion, excessive overjet, incisor angulation, molar infraocclusion, muscular habits like tongue thrust and skeletal growth pattern.
Ideal correction of deep bite requires proper diagnosis. Clinically successful results can be obtained with a number of treatment modalities which include intrusion of anterior teeth, extrusion of posterior teeth. For adult patient with skeletal deep bite surgical intervention for repositioning of dentoalveolar segment results in stable treatment outcome.
Etiology
The etiology of deep bite is classified into
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Inherent factors
Shape of the tooth: 5 Patient with long clinical incisors crowns length than compared to individuals with short clinical length.
Skeletal Pattern: 6 Skeletal overbite is characterized by horizontal growth pattern. The anterior facial height is short especially the lower third of face whereas the posterior face height is long.
Condylar growth pattern: 7 Patient with deep bite have an upward and forward growth of condyle with reduced anterior facial height. If the condylar growth is greater than the vertical growth of molar area the mandible rotates anticlockwise resulting in deepening of bite.
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Acquired Factors: 8
Muscular Habits: Loss of vertical height of tooth is caused by muscular habits like clenching, hypertonic masticatory muscle activity.
Loss of posterior supporting teeth: Premature loss of posterior supporting teeth or extraction of molars or premolars without replacement leads to mesial drifting of adjacent teeth into extraction space resulting in bite deepening.
Lateral tongue thrust: Lateral tongue thrust leads to infraocclusion of posterior teeth which leads to deep bite.
Classification
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Developmental Deep bite 6
Acquired Deepbit6It is acquired during the lifetime due to abnormal lateral tongue thrusting habit or due to drifting of the teeth into adjacent extraction space or due to wearing of tooth surface due to bruxism.
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Akerly Classification 9
Type 1: Mandibular incisors impinges against the palatal mucosa.
Type II: Mandibular incisors impinges into the palatal gingival margin of upper incisors.
Type III: Both maxillary and mandibular incisors incline lingually and impinges on the lower labial gingival and upper palatal gingival respectively.
Type IV: Wear facets on the palatal surface of the maxillary incisors and labial surface of mandibular incisors due to impingement of incisors over one another.
Diagnosis
Different diagnostic aids are:
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Clinical Examination 10
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Extraoral examination (Natural Head Position)
Patient has short square face.
Edentulous appearance
Maxillary incisors hidden behind upper lip while speaking
Corners of the mouth are below occlusal line
Distinct skin folds lateral to oral commissure
Posterior part of the face appears wide because of prominent mandibular angles
Obtuse /Normal nasolabial angle
Distinct chin button
Deep mentolabial fold
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Intraoral Examination
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Study Models:
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Cephalograms:
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Down Analysis 11 (1948)
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Steiner Analysis 11 (1953)
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Sassouni11 (1969)According to Sassouni each skeletal type is due to a positional deviation or dimensional deviation of skeletal structures.
Positional deviation: In deep bite cases the FH plane, the palatal, occlusal and mandibular plane are nearly parallel to each other and they converge far behind the patient’s profile.
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Dimensional deviation:12
The posterior facial height is equal to anterior facial height
Lower anterior face height is equal to or smaller than the upper face height
Facial breadth is equal tototal face height
The mandibular symphysisis short vertically and broad anterposteriorly
Nasion is deep seated posterior to both frontal and nasal bones.
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Burstone Analysis 11 (1979)
Skeletal Deep bite- The upper incisor to nasal floor (30.5 ± 2.1 mm), lower incisor to mandibular plane (45 ±2.1 mm), upper molar to nasal floor (26.2 ± 2 mm) and lower molar to mandibular plane (35.8 ± 2.6 mm) value decreases.
Dentoalveolar Pseudo deep bite: The upper incisors and to nasal floor and lower incisor to mandibular plane value increases while in true dentoalveolar deep bite the upper molar to nasal floor and lower molar to mandibular plane measurement decreases.
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Photographs 13
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Frontal View:
Lower third of face height is decreased.
Short, square shaped face
Wide posterior part of face, prominent mandibular angle
Maxillary incisors hidden behind upper lip on smile
Upper lip curves downwards
Corners of the mouth are below the occlusal line
Decreased inter labial distance when teeth in centric relation
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Profile view:
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Treatment Considerations 14
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Soft tissue Consideration
Interlabial gap: Interlabial gap should be maintained at 2-3 mm with teeth in maximum occlusion. In order to correct a deep bite, extrusion of posterior teeth should only be attempted in case there is no interlabial gap.
Isncision-stomion distance: It should be maintained at 3-4 mm as extrusion of posterior teeth leads to increase in this distance.
Smile line: In patients with gummy smile extrusion of posterior teeth should be avoided to correct deepbite or else it will result in excessive gingival display.
Lip length: In patients with short anatomic lip length the maxillary incisors are intruded to improve upper incisor lip relationship.
Lip Tonicity: Permanent retention of teeth is required in patient with hyperactive upper and lower lip.
Skeletal Considerations:
Functional Consideration
Bite plate is usually used to correct deep overbite in adults by allowing the posterior teeth to extrude. However bite plate should be used cautiously because of undesirable side effects related to TMJ, musculature and poor stability of attained result.
Dental Considerations
Intrusion of upto 4 mm of upper incisors can be accomplished without significant root resorption but if more than 4 mm of intrusion is required then it can be combined with intrusion of lower incisors. Periodontal disease should be under control in adult patients before the start of orthodontic treatment.
Treatment Modalities
Deep bite can be corrected by the following methods
Intrusion of anterior teeth
Extrusion of posterior teeth
Combination of both
Proclination of incisors
Surgical
Removable Appliances:
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Intrusion of anterior teeth
Sved bite plane:15 Sved modified the bite plane to produce intrusion of maxillary and mandibular anterior teeth by covering 1/3rd if the labial surface of maxillary anterior teeth with acrylic. The mandibular incisors engages the inclined plane on the palatal surface of maxillary bite plane.
Rubber Dam Elastics:16 For intrusion of maxillary incisor an acrylic and wire appliance with hook soldered on the labial wire and cleats embedded in the palatal acrylic portion are retained with the help of ¼ inch rubber dam elastics for 3-4 weeks. The elastics should pass over the incisal edges of the maxillary incisors.
An Essix intrusion appliance:17 It is made from a 1mm sheet of Essix plastic which is thermoformed over a high quality die stone cast. The sheet should extend 2-3 mm onto the gingiva. Elastic attatchment are made by cutting retentive tabs in plastic with a scalapel or bonding buttons directly to the prepared surface of plastic. Plastic covering is cut away from the teeth intruded.
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Extrusion of posterior teeth:
Anterior bite plane: First used by Miller, 18 anterior bite plane is a thickened platform of acrylic, palatal to the upper incisors on which the lower incisor occlude leaving the posterior teeth out of occlusionby 1-2 mm. This appliance has to be used while eating. Growing patient respond better as compared to older patients.
Posterior Tongue Crib: 15 In case of lateral tongue thrust habit a posterior tongue crib intercepts the lateral tongue thrust by preventing the tongue from inserting into inter occlusal space
Myofunctional appliances
Activator: Originally given by Viggo Andresen 19 in 1908 activator are used in deep overbite cases with infra occlusion of molars by allowing extrusion of molars. This is achieved by loading the palatal surfaces above the area of greatest convexity in maxillary and below the area of greatest convexity in mandible. In case of deep bite due to supraocclusion of incisors, the intrusion of incisors is achieved by loading the incisal edges of anterior teeth with acrylic. The labial bow is active and should be the area of greatest convexity to aid in intrusion of incisors.
Bionator: Bionator was developed by Wilhelm Balters. 6 Balters reduced the acrylic bulk of activator thereby making it less bulkier to wear. Deep bite due to infra occlusion of molars can be successfully managed with bionator by grinding away of acrylic in the buccal interocclusal region thereby allowing eruption of molars and premolars. It does not work if overbite is due to supra occlusion of incisors
Functional Regulator: 19 Functional regulator is a removable tissue born appliance developed by Rolf Frankel. According to him deep overbite due to infreocclusion or lingual tipping of molars is caused due to disturbance in vertical development of molars by the cheeks rather than by tongue. The acrylic buccal shield holds the cheek away and allows spontaneous up righting of molars and premolars and leveling of the curve of Spee.
Twin Block:
Twin Block was introduced by Scottish orthodontist, William Clark 20 in 1977. It is a two-piece appliance with separate maxillary and mandibular components which incorporates a guide plane that allows forward positioning of mandible. Deep overbite is corrected by trimming the occlusal cover of maxillary block occluso-distally by 1-2 mm to encourage eruption of lower molars and premolars. This prevents lateral tongue thrust and leveling of curve of Spee.
Orthopedic appliance: 21
Cervical pull appliance which consists of face bow, neck pad and force element is used for correction of deep bite cases. The inner bow engages the buccal tube on maxillary first molar and a vertically downward component of force is generated by an elastic module which engages the outer bow to neck pad. This leads to extrusion and distalizationof molars thereby rotating the mandible in a clockwise direction leading to bite opening. It should be worn 14-16 hours per day.
Fixed appliance therapy
Modified Nance Appliance: 22 Nance Appliance with a bite plane allows immediate bracket placement on lower teeth, maintains vertical dimension in patients with early loss of primary teeth, TMJ cases.
Bonded bite plane with composite resin: 23 Composite bonded bite plane can be used in Class I, Class II Div 1 and Class II Div 2. It causes intrusion of maxillary and mandibular molars.
Correction of deep bite with Begg’s technique
Anchor bends: 24 0.016” and 0.018” SS arch wire are used for bite opening, 30-50 ° anchor bend in 0.016” SS maxillary arch wire and lesser degree of anchor bends in 0.018” SS maxillary arch wire is used for progressive intrusion of central and lateral incisors. The anchor bends are given 3 mm mesial to the molar tube.
Gable bend: It is placed distal to canine and maintains bite opening attained in earlier stages of treatment. It causes relative intrusion of canine and progressive intrusion of lateral and central incisors.
Hocevar’s modification: 25 In this modification bends on both side of canine are given which causes intrusion of central incisor but extrusion of canine and lateral incisors.
Kameda’s modification: 26 In Kameda’s modification both the anchor and gable bends are given causing canine and premolars to extrude while the lateral and central incisors intrude.
Magnitude of intrusion force: According to Ricketts 27 the recommended forces for intrusion of incisors and canine is 15-25g and 60g respectively.
Correction of deep bite with edgewise technique: 28
In order to intrude teeth, 2 bends in the range of 10-15° should be given on either side of the incisors to be intruded in the opposite direction. This will cause the wire segment to lie below the plane of arch wire and then it is raised to engage into the bracket.
Correction of deep bite with Pre-adjusted appliance: 29
L F Andrews introduced first preadjusted edgewise appliance in 1970. In 1989, Bennett and McLaughlin modified straight wire appliance. Deep overbite can be effectively controlled with pre adjusted appliance when certain principles are observed.
Extrusion should be avoided and anterior bite planes should be used in beginning of treatment in low angle cases. Light initial forces should be used to avoid bite deepening and second molars should be banded from the beginning of treatment. Gentle forces should be used of Class II elastics. Bite opening curves should be used when necessary.
Correction of deep bite with segmented arch technique
Three piece intrusion arch: 30, 31 A three piece intrusion arch consists of 0.018 x 0.025 SS segment with 2-3 mm of distal extension below centre of resistance of anterior teeth placed passively in the anterior bracket and 0.017 x 0.025” TMA tipback springs which applies an intrusive force. An intrusive force perpendicular to the anterior segment and applied through centre of resistance of anterior teeth will intrude the incisor segment. If the intrusive force is placed further distally and a small distal force is applied simultaneous intrusion and retraction of anterior teeth occurs.
Ricketts utility arch: 32 Intrusion utility arch is made from 0.016 x 0.022” blue elgiloy. In the maxillary utility arch a tip back of 45°, distolingual rotation of 10-20° and an expansion of 1 cm in each side is done. Stabilization of molars is done by use of Quad Helix, lingual arch or transpalatal arch. In mandibular utility arch a 5-10° labial root torque will counteract the forward tipping action with intrusion arches.
Mulligan intrusion arch: 33 Mulligan’s intrusion arch is made using round 0.016” SS. After leveling the wire is placed with a tip back bends or “V” bends for intrusive action on incisors and extrusive action on molars.
Simultaneous intrusion and retratraction appliance-KSIR: 32 It was given by Varun Kalra and is made of 0.019 x 0.025 TMA archwire with closed 7 mm x 2 mm U loops at extraction sites. Its main indication was cases with deep bite and excessive overjet. A 90° V-bend is placed at the level of U-loop between the first molar and canine to prevent tipping into extraction spaces. A 60° V-bend located posterior to the centre of interbracket distance produces clockwise moment on the 1st molar to augment molar anchorage. To prevent the buccal segment from mesiolingual rotation a 20° antirotation bend is placed distal to U-Loop. Thhe loop is activated at every 6-8 week interval and exerts an intrusive force of 125g on anterior segment.
The Connecticut Intrusion arch: 34, 35 It was fabricated by Ravindra Nanda from NiTi Alloy and is available in 2 sizes 0.016 x 0.022 and 0.017 x 0.025”. The CIA is inserted into auxillary molar tube and anteriorly makes a contact point at the incisors. A V-bend just mesial to molar tube exerts an intrusive force of 40-60 gm on incisors.
Correction of deep bite with equiplan-Quad helix: 36
Lingual arch for intrusion and uprighting lower incisor37
Correction of deep bite with mini screw anchorage system38
Correction of deep bite with magnets39
Correction of deep bite with orthodontic and surgical management40
Surgical treatment options in deep bite cases are:
Orthodontics and inter positional genioplasty.
Orthodontics and inferior onlay mandibuloplasty.
Orthodontics and mandibular advancement.
Orthodontics and total subapical mandibular advancement.
Orthodontics and inferior repositioning of maxilla and mandibular advancement.
Orthodontics and combined maxillary and mandibular surgery.
Retention and Relapse
After completion of orthodontic treatment a maxillary removable retainer with a bite plane is needed for several years to maintain the correction. 13 The maintainance of overbite depends upon torque or axial inclination of incisors. If the maxillary and mandibular incisors are relatively upright they will have a tendency to overerupt after appliance removal. 41 Patients with vertical growth pattern have a lower tendency for relapse as compared to horizontal growth pattern. 42