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1 Class II malocclusion. Class II malocclusion. Prepared by: Prepared by: Dr Mohammed Alruby Dr Mohammed Alruby تناو الله يقلت نا كتيلؤسم نكلو قحلا رصتنا دقو الله يقلت نا كتيلؤسم نم سيل لطابلا عم لا قحلا عمو قحلا يلع Class II Malocclusion Class II Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby
2 Introduction; Classification Etiology Differential diagnosis of class II div 1 Assessment of class II div 1 Treatment of class II Camouflage treatment of class II Surgical correction Class II division 2 malocclusion Types Assessment Treatment objectives Retention Class II subdivision Class II non-extraction Class II Malocclusion Class II Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby
3 Class II malocclusion Introduction: = Class II malocclusion compromise group of specific skeletal, dental and facial features According to Angle’s classification: the mandibular dental arch and the body of the mandible present in distal relation to the maxillary one, as represent by the mesio-buccal cusp of upper 1st molars occlude between the lower 1st molar and 2nd premolar cusps = can be defined as: disto-occlusion ------- Lischer 1912 or post normal occlusion = there are two forms of class II: Division 1 and 2 Incidence: 25 -30% --- early mixed and adolescent 15 -20%: in adults Classification of class II malocclusion: According to Angle: 1-Class II div 1 2-Class II div 2 According to skeletal relationship: 1-Skeletal class 2 div 1 2-Skeletal class 2 div 2 The skeletal base may be: maxillary prognathism, mandibular retrognathism, or both According to severity of incisors: Vonder Lindin classify class II div2 into: -Type A: maxillary incisors and lateral one are retroclined -Type B: maxillary lateral incisors overlapping the maxillary central incisors which is retroclined -Type c: maxillary central and lateral incisors retroclined and overlapped by maxillary canines Etiology Class II may occurs due to a variety of causes -Prenatal -Natal -Post-natal 1-Prenatal: a-Genetic: majority of class II cases are genetic in origin, studies done on parents and children having the same type of malocclusion indicate that the facial dimension are principally determined by hereditary through gene b-Teratogenesis: administration of certain drugs during pregnancy has a potential to abnormal development of arches such as class II c-Irradiation: irradiation therapy during fetal life can also be a causative factor for class II malocclusion d-Intra-uterine fetal posture: abnormal posture of fetus such as hands across the face that affect the mandibular growth 2-Natal factors: Improper forceps application during delivery can lead to condylar damaged or fracture causing internal hemorrhage in joint area. TMJ can ankylosed or fibrosed after time lead to underdevelopment of mandible 3-Post Natal: Number of conditions that can lead to class II malocclusion as follow: a-Any condition can affect condylar growth as injury of TMJ or rheumatoid arthritis Class II Malocclusion Class II Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby
4 b-Mesial drift of maxillary molars due to premature loss of deciduous molars or Microdontia c-Abnormal function such as: mouth breathing, abnormal pressure habits, abnormal swallowing pattern, any muscular defect as short upper lip Other types of classification of class II malocclusion 1-Mc Namara classification: Two major types of skeletal combination in class II children: a-Mandibular retrusion: b-Combination of maxillary and mandibular retrusion which may be have greater vertical development The maxillary 1st molar is mesially positioned and upper anterior is retruded 2-Moyers classification: Moyers studied 697 cases of north American population and suggested six horizontal class II and five vertical pattern This method to describe the class II for the following purposes: 1-To localized and quantify any possible skeletal contributions to class II malocclusion 2-To identify dental displacements associated with class II malocclusion 3-To group cases with similar needs for ease in planning treatment 4-To determine the best treatment for special needs of particular case A-Horizontal types: Type A: = normal skeletal profile and normal anteroposterior position of jaws = mandibular dentition placed normally on its base but the maxillary dentition is protracted resulting in class II relationship and greater mesial overjet and overbite than normal = sometimes could a dental class II Type B: = midface prominence associated with a mandible of normal length = measures of maxillary prognathism is greater than normal but the mandible is in a normal relationship anteroposteriorly Type C: = class II profile, though the maxilla and mandible are further back beneath the anterior cranial base than normal = smaller facial dimension than other class II types on average = lower incisors are tipped labially while upper incisors are either upright or tipped off the base labially according to the vertical category = significantly more women than men are seen in type C Type D: = retro-gnathic skeletal profile because small mandible than normal = midface is normal or slightly diminished = lower incisors are upright or lingually inclined while upper incisors are labially inclined Type E: = class II profile with prominent midface and a normal or even prominent mandible = bi-maxillary protrusion class II malocclusion appear to be horizontal type E and the incisors are in strong labioversion = both dentition is bi-maxillary dento-alveolar protrusion Class II Malocclusion Class II Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby
5 Type F: = it is large heterogeneous group with mid skeletal class II features = it appears to be a milder form of type B, C, D, or E B-Vertical types: Type 1: = anterior face height is greater than posterior face height = mandibular and occlusal planes are steeper than normal = Palatal plane may be tipped = anterior cranial base tends to be upward = this type called steep mandibular plane case Type 2: = square face and occlusal, mandibular, and palatal planes more horizontal than normal, nearly parallel = gonial angle is smaller than normal = anterior cranial base appears horizontal = incisors more vertical position than normal, and skeletal deep bite results Class II Malocclusion Class II Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby
6 Type 3: = palatal plane tipped upward anteriorly with decreased upper anterior facial height ---- open bite = mandibular plane is steeper than normal, a severe skeletal open bite results Type 4: = mandibular occlusal, palatal lines are tipped downward, although the mandibular line is neer normal leaving the lip line unusually high on maxillary alveolar process = gonial angle is relatively obtuse = this type is rare Type 5: = Mandibular and occlusal lines are placed normally = palatal plane is tipped downward, gonial angel is smaller than normal = the result is skeletal deep bite similar to but different than the vertical type 2 = lower incisors are found in extreme labioversion whereas the upper incisors are vertical. 3-Skeletal class II classification: Sassoni 1969: a-Positional deviation: Long anterior cranial base, large cranial base angle Short ramus, small gonial angel Palate is tipped downward and backward Class II Malocclusion Class II Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby
7 The result of these combination is protrusion of maxilla or retrusive of mandible or both b-Dimensional deviation: Some individual face find that all structures are normal in position but the discrepancy in size of arches; Macro-maxilla: long maxilla, anterior position of malar bone, these individuals do not have maxillary dental crowding. Micro-mandible: short corpus, retrusive chin, normal Gonion position, over-eruption of lower anterior that lead to accentuate curve of spee c-Combination of positional and dimensional class II Criteria of class II malocclusion a-Deciduous and early mixed dentition: -Distal terminal plane of second deciduous molars -Distal canine relation -Large overjet and over bite -Poor spacing in deciduous dentition -Narrow maxillary basal bone -Retruded mandible and short mandibular length -Maxilla may be displaced forward During transition from deciduous dentition to mixed dentition there is an abnormal skeletal growth pattern in patient with class II when compared with other normal patients = upper jaw become more prominent due to larger increment of maxillary protrusion = mandible grows in less rate than the normal one = more backward and downward inclination of mandibular body leading to lesser degree of facial angle b-Late mixed and permanent dentition stage: = protrusive midface / or retrusive chin = front teeth are more out + large overjet = some cases have deep bite = change muscle activity as: flaccid upper lip, hyper active mentalis muscle, lower lip trap under prominent upper anterior, some cases may have mouth breathing or thumb sucking Differential diagnosis of class II and treatment procedures a-Growing patients: 1-Dental class II: ------ orthodontic treatment 2-Skeletal class II: Maxillary prognathism: ----- headgear Mandibular retrognathism: -----myofunctional therapy Both: ------------------------------ myofunctional therapy and headgear b-Non growing patients: 1-Dental class II: ---------------orthodontic treatment 2-Skeletal class II: Mild to moderate ------ camouflage treatment by extraction Severe: --------- maxillary prognathism: ------------ maxillary set back surgery Class II Malocclusion Class II Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby
8 Mandibular prognathism: ----------- mandibular advancement surgery Nanda: class II treatment depending on patients growing status so the treatment options are: 1-Functional appliances or fixed function to enhance the mandibular growth 2-Headgear to restrict maxillary growth 3-Camouflage by extraction of upper and /or lower premolars 4-Surgical correction of underlying skeletal discrepancy in patient which the facial growth has been completed == all the treatment options are to improve the patient: dental and facial esthetics dental function self-image quality of life. Class II division 1 malocclusion Assessment 1-Extra-oral features: -Convex profile -Decreased nasolabial angle indicate proclination of upper incisors -Incompetent lips -Everted lower lip -Deep mento-labial sulcus -Hyper active mentalis muscle 2-Skeletal features: a-Mandibular retrusion: -Decreased posterior facial height -Steep mandibular plane angle -Increased ANB angle -Decreased SNB angle -Increased angle of convexity -Increased over jet -Decreased length of mandible b-Maxillary protrusion: -Increased ANB angle -Increased angle of convexity -Increased SNA angle -SNB angle is normal -Length of maxilla increased c-Combination type 3-Intra-oral evaluation: -Class II molar and canine relationship -Proclination of upper anterior segment: this feature differentiates div 1 from div 2 -Increased over jet -Deep overbite: but in some cases may be normal bite or open bite -Deep curve of spee Class II Malocclusion Class II Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby
9 -Spacing or crowding depending upon the arch length -Proclination of lower anterior or retroclination of it depend on the muscle behavior and etiology -Narrow shaped arch and high palatal vault. Treatment of class II division 1 Treatment objectives: 1-Resolve any etiologic factors 2-Reduction of over jet and over bite 3-Relief of crowding 4-Correction of molar relationship 5-Correction of cross bite, open bite, deep bite 6-Correction of muscular abnormalities Treatment modalities: -Primary dentition -Growth modification -Camouflage treatment, extraction treatment -Surgical correction A-Growth modification: = alter the unacceptable relationship by modifying the patient remaining facial growth = class II div 1 may be maxillary or mandibular or both and these abnormalities can be corrected by functional or orthopedic appliances to reduce the intensity and prevent full changes in the skeletal base to abnormal size or direction = the presence of growth potential can be indexed from hand and wrist radiographs and also analysis of cephalometric radiograph can help for that 1-Correction of mandibular deficiency: = class II with mandibular defect can treated by using of myofunctional appliances during active growth period such as Clark’s Twin block, activator and myofunctional regulator I that can be used in cases of mandibular defect with abnormal muscle activity = in patients which at the end of pubertal growth, fixed functional appliances can be used as: Herbst, and Jasper jumper 2-Correction of maxillary prognathism: = can use headgear therapy to restrict the further growth of maxilla, headgear deliver adequate orthopedic force to compress the maxillary sutures = posterior and superior extra-oral orthopedic force inhibit anterior and inferior development of maxilla, also inhibit mesial and occlusal eruption of maxillary posterior teeth = headgear indicated in case of mandibular normal growth 3-Combined growth modification procedure: In severe class II skeletal which have both maxillary and mandibular involvement, Patient treatment with functional appliances with headgear to restrict the maxillary growth Class II Malocclusion Class II Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby
10 B-Camouflage treatment: The goal of this type of treatment is to treat the unacceptable skeletal relationship by orthodontic repositioning of the teeth in jaws that can lead to acceptable relationship and good facial esthetics Or masking the skeletal defect by change the dental structures By extraction treatment: = Treatment sequence in extraction case of class II should follow the routine protocol of extraction case = anchorage preparation can be planned based on severity and nature of malocclusion Phase I: = anchorage preparation for maxillary arch as (TPA) or second molar banding to enhance anchorage, figure of eight ligature between 2nd premolar and 1st molar = levelling and alignment begin to correct the inter-arch tooth position and axial inclination of teeth to attain good arch form = in lower arch, the treatment requires mesial migration of molars in some cases to allow correct molar relationship = gentle correction of curve of spee Phase II: retraction of maxillary anterior teeth and class II molars correction: = retraction of maxillary anterior segment may occur by enmass retraction or by retract canine firstly followed by incisors and this depend on the anchorage preparation of the case. = maxillary canine is retracted by heavy stst wires 17 x25 or 19 x 25 inch by using power chain or coil spring. Rate of canine retraction from 0.9mm to 1mm / month so it need time about 8 months until complete retraction of canine = upper incisors retraction is done by using functionless mechanics by using T loops, - in some situations we can supported by using class II elastics. = allow sufficient torque in anterior segment to prevent root in labial direction = lower arch can be used as anchorage for correction of upper one and allow some movement of molar to correct molar relationship = this phase may need about 10 months to end and after ending this phase we achieved the following: -Normal over jet and over bite -Space extraction closure -Class I sagittal relationship -Normal labio-lingual inclination of maxillary and mandibular anterior segment - Phase III: finishing and detailing: = we must finish a case in a functionally stable occlusion with no interferences during functional mandibular movements = may necessitate short term class II elastics to achieve good interdigitating, take in your consideration that in some cases class II may lead to proclination of lower anterior, that may be prevent more retraction of upper anterior = clinical observations of finishing are confirmed by lateral cephalometric radiograph to evaluate root torque of anterior and panoramic radiograph to evaluate mesio-distal tip of teeth Class II Malocclusion Class II Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby
11 C-Surgical correction: Indications: -Severe skeletal discrepancy -Adult patient with no remaining growth -Good health or mild control systemic disease ** the preparation for orthognathic surgery is necessary to remove any dental compensation that prevent and put the teeth in a favorable position to their supporting structure (bone) (pre-surgical decompensation) ** the surgical treatment options can be divided into five categories: -Maxillary impaction -Anterior maxillary sub-apical set back -Mandibular total sub-apical advancement -Combined surgery including both maxilla and mandible -Mandibular advancement 1-Maxillary impaction: Surgical correction of vertical maxillary excess Indicated in patient with large face syndrome and competent lip It either total maxillary osteotomy if excess is at anterior and posterior segment Or posterior maxillary osteotomy if excess is at posterior segment only 2-Anterior maxillary sub-apical set back: = indicated in case with maxillary excess with no transverse or vertical skeletal problems and normal size and position of mandible = use the space for 1st premolars for surgical retraction of anterior segment and reduce overjet 3-Mandibular total sub-apical advancement: Advances the mandibular dento-alveolus to reduce the overjet 4-Mandibular advancement: Indicated in most cases of mandibular defect, the procedures are either vertical ramus osteotomy or bilateral sagittal split osteotomy (BSSO) = to enhance cosmetic outcome an augmentation genioplasty could be included 5-Combined surgical approach: Indicated in maxillary and mandibular deformity Class II division 2 malocclusion Definition: condition of malocclusion which have class II molar relationship with retroclined upper incisors and also overlapped with upper laterals Retroclination of upper incisors is a manifestation of dental compensation to overcome skeletal background Types of class II division 2: Type A: the permanent incisors are palatally retroclined without occurrence of any crowding Type B: the maxillary central incisors are palatally retroclined and laterals are labially tipped or lateral overlaps the centrals Type C: the four maxillary incisors are retroclined palatally with canine labially positioned Class II Malocclusion Class II Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby
12 Extra-oral assessment: -Patient have facial profile and square face -Decreased lower anterior face height -Increased naso-labial angle -Normal upper lip and lip seal, thin upper lip -Hyper active mentalis muscles with accentuated labio-mental groove -Masseter and temporalis muscle are wide Intra-oral assessment: 1-Molars in distocclusion 2-Retroclined central incisors 3-Deep overbite 4-Some cases have excessive wear in the lower anterior teeth N: B: Bryant et al: studies concluded that, the maxillary central incisors crown in patients with class II div 2 malocclusion were found to be bent lingually in relation to their roots. This will be limitation on torque of their roots 5-Lower arch is flat and may or may not show individual teeth irregularities 6-Exaggerated curve of spee 7-Little or no overjet N: B: upper central incisors are bent lingually with ill-defined cingulum In some cases, the deep over bite may be excessive so that the incisal edges of upper and lower incisors may impinge over the labial and palatal gingiva causing their traumatization 8-Upper and lower arches are usually broad and the buccal cross bite is uncommon, 9-Some cases the maxillary inter-canine width may be wider than normal Cephalometric assessment: 1-Average FHMP angle or low 2-Four planes of face are rarely parallel 3-Small cranial base angle which position the glenoid fossa and condyles more inferior and anterior 4-Small gonial angle 5-Small Y axis angle 6-PFH is usually equal to AFH 7-LAFH is smaller than UAFH 8-Large inter-incisal angle Shudy listed the following: Excessive cranial base bending Lowering glenoid fossa Exceeds the vertical condylar growth 9-Anterior posterior assessment indicating class II 10-Sassoni listed the following: -Facial breadth tends to equal to the total height that giving the face square appearance -Increased bi-gonial width -Flared gonial process ------------- indicate strong masseter action -Nasal apertures are broad, broad maxilla -Palatal vault is flat -Pharyngeal space is large (patient seldom mouth breather) Class II Malocclusion Class II Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby
13 Functional assessment: Lips: -Upper lip long and flat -Lower lip thick and hypertrophied -Hyper active mentalis muscles -Upper and lower lips are sealed together -Lower lip usually covers more than one half of upper incisors crown during rest -During function the lower lip exert high force on upper incisors that prevent active proclination Tongue: -Tongue space is large -No forward tongue thrust -Seldom interfere with breathing Muscles of mastication: -Posterior vertical chain of muscles (temporalis, masseter, and internal pterygoid) are attached more anteriorly on mandible and pulls vertically in straight line -Molars lie directly under this force which prevent any active correction of deep bite -Flared gonial processes indicate hyperactive temporalis Path of mandibular closure: = patient with class II div 2 with deep bite showed true posterior displacement of mandible when closing from rest position to occlusion = Ballard stated that, most cases of class II div 2 has downward and forward position from the habitual resting position so during occlusion the position is changed into more posterior position ----- posterior displacement = others reported that, the maxillary incisors have slim and shallow cingulum which permit sliding of lower incisors that lead to posterior displacement Treatment objectives: -Relief of crowding -Correction of incisors inclination -Correct overjet and overbite -Correct molars relationship -Relief of gingival trauma Treatment modalities: A-Growth modification: Change the position of upper incisors to be in normal angulation that lead to change the case to class II div 1 then treatment case as division 1 -------- by growth modification -Mandibular deficiency -Maxillary prognathism -Both B-Adult treatment: Same as class ii div 1 but: Ricketts in the bio-progressive technique described six steps which are necessary for treatment of class II division 2 malocclusion. 1-Advancement, torque and intrusion of upper incisors: the basic principles is to correct the over bite before the overjet but in div 2 this not occurs because the original retroclination of upper incisors usually interfere with intrusion of these teeth so: create overjet first then Class II Malocclusion Class II Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby
14 correct overbite, this usually carried out by using maxillary utility arch 0.016 x 0.022 with tip back 45 degree and toe in 10 to 20 degree Anchorage preparation using Nance appliance, TPA, maxillary headgear. Nance is preferred because it can be used as bite plate for overbite reduction Buccal segment can also be stabilized by using 0.016 x 0.022 stst sectional arch in occlusal molar tube. 2-Intrusion of lower incisors and cuspids: This can be achieved by using lower utility arch 0.016 x 0.016 that exert force 75gm to intrude the lower anterior and upright the lower molars 3-Correction of buccal segment: Upper and lower buccal teeth are aligned and levelled by using buccal sectional arch, then the molar relation is correcting by using class II elastics 4-Support upper incisors: Added another torque to upper incisors and close the residual space by using retraction arch with vertical helix 0.016 x 0.016 5-Idealizing the arch and finishing: Using 0.018 x 0.022 is placed to allow more natural arch to developed Torque 22 for U 1 Torque 14 for U 2 Torque 7 for U 3 Torque 7 for L 3 Note that the above treatment is considered for case with mild class II div 2 which space deficiency about 5mm which the case between extraction and non-extraction treatment In severe cases: Early treatment by using cervical headgear and utility mechanics Late treatment by extraction of 1st premolars upper and 2nd premolars lower. Then align upper incisors with optimum torque N: B: Extraction treatment lead to deepening the bite ---- decreased facial height Distalization treatment: lead to opening the bite ----- increase the facial height Retention and stability Reduction of inter-incisal angle and establishment of guidance between maxillary and mandibular incisors is important for stability. Over correct the occlusal relationship It is recommended to continue use of headgear and functional appliances like activator till the active growth is completed Case with deep bite but after treatment increase the lower facial height has less tendency for relapse. Class II Malocclusion Class II Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby
15 Class II subdivision Have a characteristic of class II and class I: distal molar occlusion in one side and class I occlusion in other side Etiology: 1-Skeletal a symmetry: -Craniofacial syndrome, genetic mutation -Hemi-facial microsomia -Abnormal morphology of maxilla or mandible where one side is larger than the other side in anterior posterior or vertical or transverse dimension -A symmetry in the cranial base can cause some symmetries in positioning of left and right glenoid fossa, which can rotate a symmetric mandible in relation to maxilla, produce subdivision 2-Dental a symmetry: -Early loss of primary second molar on one side with unilateral loss of leeway space -Ankylosed primary molars -Ectopic eruption of maxillary 1st molars -Congenital missing teeth -Caries with loss of inter-proximal tooth structure -Tooth size discrepancy -A symmetric crowding -Midline discrepancy (due to loss of primary canines and ectopic lingual eruption of mandibular lateral incisors) -Supernumerary teeth -Habits as thumb sucking History and etiology: Alavi: the 1st determine that class II subdivision result mainly from a symmetry in the mandibular 1st molars Rose: confirmed those results and concluded that class II subdivisions occurs from distal positioning of the mandibular 1st molar on class II side Janson: subdivision due to dento-alveolar a symmetry without unusual skeletal or positional a symmetry Azevedo: subdivision is dento-alveolar with minimal skeletal involvement. Nanda et al: studied the skeletal and dental a symmetry in class II subdivision and they found that: -Subdivision is a symmetry mandible that is shorter and positional posteriorly -Total mandibular length and ramus height were shorter -Second factor was mesial positioning of maxillary first molar on class II side in 20% -Third factor was distal positioning of mandibular 1st molar on a symmetric class II side mandible ---- 19% Class II non-extraction treatment In developing class II: depend on the age of patient and the part of defect either maxilla or mandible, maxillary excess, mandibular defect, or both types = extra-oral appliance: headgear and its direction can treat long face or short face = intra-oral appliance: Class II Malocclusion Class II Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby
16 a-Intra-maxillary: Removable: lip bumper Fixed: -Open coil -Jons jig -Distal jet -Pendulum -First class -Magnets -Lip bumper -TPA -Biometric Wilson b-Inter-maxillary: -Forsus appliance -Herbst -Jasber jumber -Magnets -Twin bite force corrector Class II Malocclusion Class II Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby
