Class III Malocclusion

1. 1 Class III malocclusion Class III malocclusion Prepared by: Prepared by: Dr Mohammed Alruby Dr Mohammed Alruby نكلو لطابلاو لطابلا ينب هكرعلما نوكت امدنع لهيضف دايلحا نكلو لطابلاو لطابلا ينب هكرعلما نوكت امدنع لهيضف دايلحا لطابلاو قلحا ينب هكرعلما نوكت امدنع هيمرج دايلحا نوكي لطابلاو قلحا ينب هكرعلما نوكت امدنع هيمرج دايلحا نوكي Class III Malocclusion Class III Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby

2. 2 Introduction Types Factors affect development of class III Differential diagnosis Objective treatment and its limitation Principle of treatment Treatment mechanics Classification of class III Treatment of maxillary deficiency Treatment of mandibular excess Camouflage treatment of class III Treatment approach for camouflage treatment Growth modification of class III malocclusion Treatment of modifications modalities Class III Malocclusion Class III Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby

3. 3 Introduction: = According to Angle, class III is a type of malocclusion in which the lower molars and dental arch occludes mesial to the maxillary one = Lisher introduce the term malocclusion for Angle class III = the unilateral arrangement of class III is called class III subdivision Prevalence: Class III is the least common type of malocclusion in many communities occurring less than 5% in British population, ((Foster and Day 1974)) 5: 10 % among European population, this ratio tends to increase by age = also class III show racial variation, it was about 1% among Jewish and 7% among American negro = although class III is infrequent but it presents the most difficult treatment in orthodontic practice = it is probably true to say that greater proportion of class III are beyond correction by orthodontic treatment (Foster) Types of class III: Moyers types: There are three distinct types of class III or mesio-occlusion 1-True Angle class III, skeletal type: It is skeletal dysplasia involving mandibular hypertrophy, or deficient midface or both This type is called skeletal class III 2-Pseudo class III or apparent class II: It positional mal-relationship, reflex functional mandibular protraction 3-Dental class III: It is an abnormal axial inclination (lingo-version) of maxillary incisors with no real class III features The main etiologic factors influencing development of class III: 1-Skeletal factors: a-Anterior posterior discrepancies: Position: The upper jaw is positional backward in relation to the lower jaw or in relation to the cranial base The lower jaw is positional forward in relation to the upper jaw or in relation to the cranial base Size: The upper jaw is too small; the lower jaw is normal The upper jaw is normal; the lower jaw is too large The upper jaw is small and the lower jaw is large b-Lateral discrepancies: Responsible for buccal cross bite associated with class III which may be unilateral or bilateral Discrepancies in relative width of upper and / or lower arch may cause unilateral or bilateral cross bite Narrow maxilla or wide mandible or both, also the lateral discrepancies may be sequelae for anterior posterior discrepancies, for example when the maxilla too small, it will be collapsed and does not diverge posteriorly resulting in posterior cross bite c-Vertical discrepancies: It is responsible for the degree of over bite or open bite that may accompanied the skeletal class III Maccollin 1955 divided class III according to facial height and value of gonial angle into 2 groups Class III Malocclusion Class III Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby

4. 4 -Group 1: characterized by short maxilla large mandible increased facial height high gonial angle presence of some degree of open bite -Group 2: characterized by: Normal maxilla Large mandible Normal or reduced facial height Normal or reduced gonial angle Presence of some degree of deep reversed bite = the skeletal factors determine the severity of the occlusal problem and provide the main limiting factors for treatment 2-Dental factors: Premature loss of deciduous molars: May be responsible for production of pseudo class III The loss of deciduous molar in a critical period of development cause the patient to protrude his mandible to cut and eat foods on his frontal teeth, so that the lower incisors teeth slide over the labial surface of maxillary one, causes retroclination of maxillary incisors and proclination of mandibular incisors with the development of anterior cross bite and deep reversed over bite which exaggerated by mandibular over closure 3-The muscular factors: In pseudo class III, the normal muscle reflex acts to maintain the mandible in protruded position The large tongue plays a part in protruding an open bite in cases of small maxilla 4-Hereditary: Skeletal class III shows functional tendency, the classic example is the Hapsburg family Diagnostic criteria Extra-oral examination: 1-Profile: straight or concave 2-The vertical facial balance: Sassoni classified class III inti two groups; -Class III open bite cases: in such cases, there is an increased in the lower anterior facial height, large gonial angle, presence of open bite -Class III deep bite cases: characterized by: reduced lower anterior facial height and low gonial angle, presence of deep bite Among the above 2 groups there is a variety of class III may be present 3-Size and position of maxilla: In some cases, the maxilla is normal, the mandible is long and Prognathic, but in some times there is a combination of small retrognathic maxilla and large Prognathic mandible may be found 4-Soft tissues: Class III Malocclusion Class III Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby

5. 5 Lips: In classic Hapsburg family the upper lip is short and lower lip everted In most cases the lips are sealed together at rest except in class III open bite combination where’s the lips may be a part in such cases the gingiva will exposed on smiling Chin: The chin is prominent and printed in class III open bite, prominent and round in class III deep bite Intra-oral examinations: Tongue size: In class III, the tongue usually matches the size of lower arch, in most cases the tongue is large and may cause opening of mandibular incisors Tongue position: In case of large tongue, wide mandible, small deficient maxilla, the tongue usually occupies a low posture Tongue behavior: As a result of its large size and its low posture, it will behave abnormal function It may thrust between the upper and lower incisors during rest and swallowing causing an anterior open bite, in addition the lack of its molding effect on the palate, may produce narrow maxilla and high V shaped palatal vault The large tongue in class III cases present a major limiting factors in reducing the lower parameter by retroclination of mandibular incisors Gingiva: Gingival recession and periodontal disease are often seen in the lower anterior segment due to cross bite and disuse atrophy of the gingiva Dental examination: Angle classification: the lower dental arch and the body of the mandible occlude mesial to the maxillary one Overjet: Reversed in most cases, it may be zero in edge to edge bite cases Overbite: Reversed in most cases Cross bite: There may be edge to edge bite or anterior cross bite. Posterior cross bite is also common which may be unilateral or bilateral Missing teeth and impaction: In cases of deficient, the maxilla is narrow, collapsed and there may be congenital missing of lateral incisors and 2nd bicuspid and impaction of cuspids and third molars is common. There is commonly seen in cleft palate cases On the other hand, the lower arch is wide, the lower teeth are normally aligned, the lower 3rd molars are rarely impacted Mandibular path of closure from rest position to occlusion: = in class III cases the path of mandibular closure from rest position to occlusion is primarily straight however forward displacement of mandible may occur due to over closure particularly in pseudo class III where the loss of deciduous molars and sliding of mandibular incisors on the labial surface of maxillary one facilitate over closure and forward displacement of the mandible = in cases of narrow maxilla some lateral shift to the right or to the left may occurs, this shift developed early due to premature contact at the area of deciduous canine Class III Malocclusion Class III Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby

6. 6 Habits: Thumb and finger sucking: Thumb sucking in class III may be helpful rather than hindering factors, thumb sucking maintains the upper incisors over the lower one despite of class III relationship and thus prevent development of anterior cross bite and prevent occurrence of pseudo class III malocclusion But in sometimes it is responsible for production of anterior open bite particularly in class III open bite tendency Tongue thrust: As mentioned before, when the maxilla is narrow and collapsed the tongue assumes a lower position and may be thrust between the upper and lower incisors ----------- anterior open bite Class III due to micro-maxilla: -Narrow collapsed maxilla with high palatal vault -Crowding of maxillary incisors -Impaction, congenitally absence of teeth particularly in cleft palate cases -Narrow nasal aperture Class III due to macro-mandible: -The lower lip is tight against the mandibular incisors, tipping them lingually -Edge to edge bite or anterior cross bite -Symphysis is high and narrow -The chin is pointed and prominent -Long styloid processes are found -The mandibular dental arch is wide and mandibular teeth are well aligned – impaction of lower 3rd molars rarely occurs -Gingival recession and periodontal disease of lower anterior segment Class III with open bite: -Is primarily open bite with palatal deficiency or large mandible -This combination has the most worse prognosis: if correction of open bite attempted by rotating the mandible upward, the chin protrusion will increase, on the other hand, if correction of class III is attempted by rotating the mandible downward and backward, the open bite will increase -Even surgery in such cases is of little value because the posterior teeth will be interfering with closing the lower face height -Probably combined prosthetic and surgical approach would be indicated The alternative treatment: Lefort I for impaction of maxilla and surgical rotation of the mandible followed by orthodontic treatment Class III with deep bite: -It is primarily deep bite associated with small maxilla and / or large mandible, this combination has probably favorable prognosis -If the maxilla is deficient, the opening of mid palatal suture by rapid maxillary expansion may be provides satisfactory enlargement of maxilla -If the mandible is Prognathic, it is downward and backward rotation may reduce class III and deep bite at the same time Class III Malocclusion Class III Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby

7. 7 Cast analysis a-Upper arch: If class III occurs due to deficiency in maxilla, the maxilla appears narrow tapered, collapsed with high V shaped palatal vault Crowding of maxillary incisors is common features Retroclination of maxillary incisors On the other hand, the maxilla may be of normal size in such cases the mandible will be larger than normal, in both cases crowding is common features in maxilla also retroclination of maxillary incisors b-Lower arch: In cases of deficient maxilla, the lower arch is of normal size, the lower teeth are well aligned and rarely crowded, in case of large mandible and large tongue, spacing of lower incisors can be seen The lower anterior teeth are proclined in case of cross bite, but may be retroclined in true class III malocclusion due to hyper active mentalis muscle, this commonly seen in edge to edge bite cases Cephalometric analysis SNA: may be normal or reduced SNB: may be normal or increased ANB: less than 2 degree or reduced SN –pog: usually increased due to chin prominence or more than 80 degree Facial angle; increased Angle of convexity: reduced to negative value Gonial angle: increased in class III open bite cases and normal or less in class III deep bite cases FMP: as in gonial angle U1 to FH: reduced L1 to MP: increased U1 to L1: increased According to Sassoni: -Class III patient having a small cranial base angle bringing the glenoid fossa and condyles more anteriorly relative to sella turcica -Class III may be associated with deficient maxilla or large mandible (small SNA or large SNB) -Larger gonial angle and steep mandibular plane resembling an open bite cases -The palate is tipped upward posteriorly and downward anteriorly 1-Pseudo class III: Shows normal values for the basic skeletal criteria. Lateral cephalogram should take for such patient with condyles in most retruded position within the glenoid fossa using wax bite insitue There is a mild deficiency in maxillary dento-alveolar length can be seen in the profile analysis, this due to retroclination of maxilla, there is mild skeletal class III relationship The vertical analysis will be normal 2-Skeletal class III: a-Midface deficiency: Cephalometric analysis of such cases display the following morphologic criteria: -Class III maxilla-mandibular relationship -Reduced SNA angle Class III Malocclusion Class III Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby

8. 8 -Normal SNB angle -The profile analysis shows maxilla and normal mandibular length but the mandibular dento-alveolar unit may be increased due to proclination of mandibular teeth -vertical analysis demonstrates normal lower face height but mildly deficient upper face height and maxillary height b-mandibular prognathism: such as display the following cephalometric criteria: -normal SNA angle -increased SNB angle -decreased cranial base angle -increased face height -normal upper face height - in severe mandibular prognathism there may be an increase in maxillary dento-alveolar unit by tipping of maxillary incisors labially to obtain function with the excessively protruded mandibular incisors -large gonial angle and steep mandibular plane c-mid face deficiency and mandibular prognathism: it is combined type for which treatment is differ and prognosis is somewhat better than serious mandibular prognathism. Differential diagnosis of class III = true class III should differentiate from pseudo class III, the patient should examine for the following items: 1-profile: it is concave in both types, but is improved as the mandible drop from occlusal to rest position only in pseudo class III 2-TMJ palpation: palpation by tip and index finger during opening and closure is diagnostic, the condyles are felt outside the glenoid fossa during closure in pseudo class III cases 3-Path of mandibular closure: there is forward displacement, over closure and sometime lateral shifting of the mandible from rest to occlusion in pseudo class III 4-Molar relationship: in true class III malocclusion, there is a distinct class III relationship in both postural and occlusal position, while in pseudo class III, there is shift from class I in postural position to class III in occlusal position 5-The child with pseudo class III can be forced to bite back in edge to edge bite which is impossible for true class III cases 6-In case of pseudo class III there is reversed deep bite and mandibular overclosure, there is also anterior cross bite ** Mc callin 1955 differentiate 3 types of class III malocclusion: Type 1 deficient maxilla: -Small maxilla -Increased anterior facial height -Long mandible with high FMP and gonial angles -Tendency toward open bite Type 2: mandibular prognathism: -Normal maxilla but long mandible -There is true mandibular prognathism -Normal or low FMP and gonial angles Class III Malocclusion Class III Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby

9. 9 Type 3: pseudo class III: -History of premature loss of deciduous molars -Mild skeletal class III pattern -Reversed deep bite and mandibular overclosure -Anterior cross bite -The condyles can felt outside the glenoid fossa -The patient can bite back into edge to edge bite Factors affect treatment planning of class III 1-Skeletal relationship, incisal inclination and overjet: Careful assessment of skeletal relationship, incisal inclination and overjet is very important to determine the type of tooth movement that used either tipping or torque movement For example: if the case is dental class III on skeletal class I or mild class III with small reversed overjet and minimal incisor inclination, the tipping movement of upper incisors forward and / or the lower incisors backward and may be quite sufficient to correct the incisors relationship while, in sever class III cases where there is a large reversed overjet, tipping movement of incisors is unsatisfactory and greater inclination of incisors is required to correct the condition. So the torque or bodily movement is required, on the other hand if bodily movement of incisors is fails to overcome the effect of skeletal discrepancy, the condition is beyond the scope of orthodontic treatment and surgical re-positioning of the jaws is required 2-Incisor overbite: Incisor over bite is important to determine type and direction of the tooth movement, possibility and prognosis of orthodontic treatment 1st condition: Case with deep reversed over bite and small reversed overjet can be treated by simple tipping of upper incisors forward and / or lower incisors backward The prognosis is good 2nd condition: Case with edge to edge bite, tooth movement is preferred to be bodily, because tipping movement of incisors tend to open the bite. Some extrusion is required to obtain normal overbite 3rd condition: Case with minimum to moderate open bite Bodily movement and extrusion are required 4th condition: Case with severe anterior open bite The problem may be beyond orthodontic treatment and required surgical intervention 3-Tongue size and function: Tongue size is important to determine whether the mandibular incisors can be retroclined during treatment or not, and whether the lower arch parameter can be reduced or not Assessment of tongue size and function determines whether there is physical barrier against correction of anterior open bite 4-Crowding or spacing: In upper arch crowding is common finding, assessment of the degree of crowding is important to determine the mode of space creation Class III Malocclusion Class III Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby

10. 10 In cases of minimum crowding expansion is sufficient to relieve crowding, but in cases of severe crowding, extraction of U5 may be necessary but as a general rule, extraction in the upper arch should be avoided and if necessary should be delayed after expansion and re-evaluation == crowding is less common in the lower arch but if extraction of L4 is occurs with construction of maximum anchorage is necessary == if the lower arch is spaced, this indicate large size of tongue and extraction is contraindicated because the suspected failure in space closure Objectives of treatment and its limitation 1-Correction of crowding: == upper arch: In class III cases, crowding is common finding in the upper arch, as a general rule, extraction in the upper arch in class III cases should be avoided as possible, but if should be carried as in cases of severe crowding, it should be delayed as far back as possible, until correction of incisors relationship is completed. Then the case is re-evaluated, if crowding is so great the extraction of U5 is done and relief of crowding takes place. The rest of extraction space can be closed by bringing the maxillary 1st molars forward using class III elastics, this also help in correction of anterior posterior molars relationship Mild and moderate crowding: of upper arch can be relieved by enlarging the maxilla through expansion using palatal spring, S spring or expansion screw == lower arch: Crowding of lower arch is not common but if present, extraction of 1st premolar or even incisors can be done to relief crowding and if possible to reduce the anterior posterior dimension of the lower arch The major limiting factor to do this is the large size of tongue which prevent retraction of mandibular anterior segment, and cases failure in closure of the extraction space. So the careful assessment of the tongue size should be made before taking such decision 2-Correction of reversed overjet (anterior cross bite): Correction of reversed over jet or anterior cross bite can be carried out by proclination of maxillary incisors and / or retroclination of mandibular incisors The major limiting factors to this correction are: -Anterior posterior jaw relationship -Presence of open bite -Large tongue In more severe skeletal class III discrepancies, the incisors cannot move sufficiently to overcome the effect of dental base relationship In the presence of open bite, even if the incisors moved sufficiently to produce correct incisors relationship they will not be mentioned in that position without a positive incisal overbite, so that open bite could be causes relapse of the condition Finally, the tongue may be interfering with retroclination of mandibular incisors and this prevent any corrective treatment. 3-Correction of incisal overbite: a-Correction of deep reversed bite: Depends mainly on the correction of reversed overjet Class III Malocclusion Class III Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby

11. 11 If the incisors can be placed in correct anterior posterior relationship during growth period, the deep bite can be reduced into a normal value by vertical development of buccal dento-alveolar segments b-Correction of anterior open bite: It is much more difficult and limited by: tongue size and behavior, vertical dimension of the face A minor degree of open bite may be corrected by extrusion of upper and / or lower incisors Severe anterior open bite is a result of skeletal discrepancy and cannot be treated by orthodontic alone 4-Correction of buccal segment relationship: a-Anterior posterior relationship: If being necessary the correction of molar relationship, can be achieved by moving the maxillary 1st molars forward into the extraction space of U5 (in case of U5 extraction for correction of severe maxillary crowding using inter-maxillary class III elastics) But in cases of mild to moderate crowding which can be relieved by expansion Extraction should be avoided and it is thought un-necessary to correct the anterior posterior molars relationship. The limiting factors is the degree of anterior posterior skeletal discrepancies b-Correction of buccal cross bite: 1-Unilateral cross bite: Slight narrowness of the maxillary arch may result in unilateral buccal cross bite. It is desirable to correct unilateral cross bite which involve initial premature contact and causes deviation in the path of mandibular closure (translocated closure). Lateral expansion of upper arch may correct the case 2-Bi-lateral cross bite: In cases of narrow collapsed maxilla where there is bilateral cross bite, the dento-alveolar maxillary expansion is unsatisfactory because it cannot compensate the lack of width of maxillary base (lateral skeletal discrepancy) so, it is thought that: bilateral symmetrical cross bite in which the mandibular closure is not deviated are often accepted. The rapid maxillary expansion by splitting of mid-palatal suture is satisfactory Early treatment of class III 1-Treatment of pseudo class III: = The main objectives in the treatment of postural class III is the correction of incisors relationships and prevent translocated mandibular closure. = In primary dentition and early mixed dentition, pseudo class III can be treated by occlusal equilibration and restoration of missing deciduous molars Steps and purpose of occlusal equilibration: First locate and removes all teeth interferences, this may involve grinding of primary teeth and moving of permanent teeth which causes interference. This important to removing of all areas of premature initial contact which may causes translocated mandibular closure and / or lateral deviation of the mandible. Grinding takes place by using of articulating papers and abrasive stone and it is better to try it first on the dental cast. Do not grind the permanent teeth in mixed dentition but it is better to be moved orthodontically since the areas removed may be needed later for the occlusal stability after growth is completed = the results of this treatment is satisfactory in primary dentition but less favorable in mixed dentition Class III Malocclusion Class III Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby

12. 12 **** If the results of occlusal equilibration are unsatisfactory we can use alternative mechanics: = Again we say the main objectives is to move the maxillary incisors forward and / or the mandibular incisors backward. Which teeth should be moved is depend upon the axial inclination of incisors Proclination of maxillary incisors: = This can be achieved by using of removable maxillary appliances involving palatal spring, S spring, or expansion screw = Addition of acrylic posterior bite plane is necessary to open the bite anteriorly Retroclination of mandibular incisors: = This can be done by using of short labial arch on mandibular incisors or by using of fixed appliance utilizing inter-maxillary traction = There must be sufficient space for retroclination of mandibular incisors and the limitation caused by tongue must born in mind = Another form of mechanics is using of inclined plane fixed on mandibular incisors and using maxillary short labial arch to prevent forward movement of maxillary incisors Proclination of maxillary incisors and retroclination of mandibular one at the same time: = This achieved by using inclined plane as acrylic inclined plane that cemented on the mandibular incisors using a stiff mix of zinc oxide eugenol = on closing the mouth, the mandible is forced to be retruded and thus the mandibular incisors move lingually and the maxillary incisors moves labially = the level of appliance should be ground carefully so that all teeth are in even contact with it, this permit an even distribution of load and prevent traumatic occlusion. = periodic observation of the appliance is necessary for this purpose; the child is instructed to eat semisolid foods for at least one week = if marked improvement not seen quickly with 3 weeks, the case must be re-assessed for mis- diagnosis Remember: The continuous forward mandibular displacement due to pseudo class III if untreated early, it will enhance mandibular growth at the condyles resulting in mild class III skeletal pattern in adolescent, so that the treatment is more difficult in older children 2-Treatment of mid face deficiency: The early treatment of mid face deficiency can be achieved by using functional appliance which produce satisfactory results in many cases. In mid face deficiency ------- Frankel functional regulator III or reversed activator can be used ** Levin et al reported patient treatment from skeletal and dental class III by full time wear 2 -5 years and retention for 3 years has a significant change in maxillary and mandibular position with more lingual tipping in lower incisors == In severe mid face defect Delaire face mask is the appliance of choice Good results can be obtained by this device which translate the maxilla forward, improve the skeletal profile and restrain mandibular growth With splint attached to maxillary arch, the success of treatment is declined at age 10 to 13 years of age ** suited in children with minor to moderate skeletal problem, it is better to delay the maxillary protraction until molars and incisors can involve in anchorage ** do maxillary expansion if needed, there is no reason to expand maxilla just to improve protraction Class III Malocclusion Class III Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby

13. 13 ** the maxillary splint has hooks for attachment to face mask that is located at canine – primary molars area above the occlusal plane, so the force vector near the center of resistance of maxilla. Force 350 -450 gm / side for 12 to 14 hour /day ** in some cases need slight downward direction of elastic traction to improve the vertical defect N: B: Types of face mask: -Delaire type: offer good stability, more bulky and can cause problem during wearing eye glass and sleeping, appear to be ill fitted to face petit type: more comfort during sleeping, less difficult to adjust 3-Treatment of mandibular prognathism: In mild cases, the following appliances can be used: a-Frankel regulator III or reversed activator: that designed to rotate the mandible downward and backward and guide eruption of teeth, so that the upper posterior teeth erupt downward and forward while eruption of lower teeth is restrained = rotate the occlusal plane to direction that favor correction of class III = bite registration done on mandible is in most retruded position b-Chin cup: = Extra-oral force is directed against mandibular condyle = rotate the mandible downward and backward which can lead to increase in facial height = strep can directed in several direction according to the type of malocclusion = it has limited application because most of patient need surgery Graber reported that the use of chin cup utilizing heavy extra-oral traction on mandible has the following advantage: -Rotate the mandible posteriorly -Restrict the vertical condylar growth -Decrease the gonial angle -Slightly rotate the corpus of maxilla clock wise The results are the improvement of skeletal profile and maintain of FMP angle within normal range c-Reversed activator: This design rotates the mandible posterior and redirect the horizontal mandibular growth into more vertical direction, so that reversed activator is suitable for correction of class III deep bite Class III Malocclusion Class III Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby

14. 14 4-Treatment of combined mid face of the mandible: It is less difficult than mandibular prognathism alone. Devices which combines the mid face retraction and mandibular retraction can be used as: -FR III -Activator – reversed -Face mask -Chin cup Treatment of class III in adolescence The general strategies for treatment of class III in adolescence includes: -Forward displacement of mid face -Inhibition of mandibular growth -Redirection of mandibular growth -Dental and alveolar repositioning 1-Treatment of mid face deficiency: In mild case: Delaire suggested the use of face mask attached to fully banded maxillary arch to apply heavy protraction force to produce forward mid face displacement The direction of force is determined by steepness of occlusal and mandibular planes In severe cases: surgical repositioning of maxilla is indicated 2-Correction of mandibular prognathism: It is more severe problem than mid face deficiency, the treatment planning depends on the vertical skeletal morphology of the face In mild cases: = When the freeway space is larger and the mandibular plane in not steep, the mandibular prognathism can be treated by redirection of mandibular growth, dento-alveolar repositioning or even face mask therapy. The lip length and function are important consideration in reducing the vertical growth. = Grabber reported success with chin cup treatment in mild class III in adolescence = Combined FRIII or reverse activator with fully banded appliance in both arches is useful only in mild cases = Correction of mild to moderate class III in adolescence also can be achieved by fixed appliance utilizing inter-maxillary class III traction to move the maxillary teeth forward and the mandibular teeth backward In severe cases: Surgical repositioning of the mandible can be carried out 3-Combined mid face deficiency and mandibular prognathism Combined treatment utilizing maxillary protraction and mandibular retraction as; FRIII or reversed activator, face mask, and chin cup can be used in mild cases Surgical correction repositioning of both arches is indicated in severe cases. Class III Malocclusion Class III Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby

15. 15 Camouflage treatment of class III These class III patients that often passed their pubertal growth spurt and major growth component is completed. Skeletal deformity from mild to moderate, this treatment can also be used in mild open bite cases Factors affect camouflage treatment: 1-Growth: After finishing of growth stage and all treatment need pass the growth period, the cases require non- surgical treatment approach or extraction approach 2-Limitation of tooth movement: In cases of class III malocclusion: dental compensation occurs mask the severity of underlying skeletal discrepancies, so non-extraction treatment will enhance the dental compensation that can affect the general condition Excessive proclination of maxillary incisors and lingual tipping of mandibular incisors could result root to close to palatal and labial alveolus which could compromise periodontal health 3-Psychology, treatment coast and relapse: Camouflage treatment should consider patient willingness, motivation and expectation Patient should a ware about the economies of treatment and expectation of limitation of results Cases good for camouflage treatment: 1-Class III with mild to moderate severity 2-Absence of skeletal facial a symmetry 3-Hypodivergant class III pattern 4-Lack of posterior cross bite or mild posterior cross bite 5-Subjects who have passed the active growth period for orthopedic treatment of maxillary protraction and chin cup therapy 6-Presence of good alveolar bone support in mandibular anterior symphysis and maxilla to accommodate mandibular anterior retroclination / maxillary anterior proclination Cases who not good for camouflage treatment: 1-Acute naso-labial angle which indicate further proclination of maxillary anterior could worsen the profile 2-Limited possibilities of further retroclination of mandibular incisors 3-Large negative overjet 4-Class III genetic etiology because high tendency for relapse 5-Patient with skeletal facial a symmetry 6-Open gonial angle and open bite cases Treatment approach for camouflage treatment: 1-Non-extraction approach; Is used for cases that have minor crowding that can be resolved easily by arch expansion or incisors proclination -Expansion in both arches -Proclination of incisors -Distalization of lower arch -Using MEAW technique: this is Multiloop edge wise arch wires, that produced by Kin 1987 this arch wire has horizontal and vertical loops that allow more flexibility to the arch wire which permit horizontal positions Class III Malocclusion Class III Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby

16. 16 2-Extraction approach: Extraction is planned to allow relief of crowding and correction of negative overjet and overbite Choice of extraction: -Mandibular incisors: In case of minor crowding or Bolton discrepancy but need to mismatch the midline between upper and lower—lower bonded retainer is indicated -Upper 2nd premolars and lower 1st premolar: Classic form of extraction in class III case to allow relief of crowding and correct molar relationship -Only lower 1st premolars -Mandibular 2nd molars: That allow significant distal movement in lower arch by using intra-oral implant or by using headgear cervical Advantages: 1-Rapid eruption of 3rd molars 2-Prevent late incisors crowding 3-Reduce the quality and duration of therapy with fixed appliance 4-Facilitate distal movement of 1st molars and anterior dentition 5-Less residual space is left after end of treatment 6-Reduce probability of relapse 7-Maintain the facial esthetics 8-Avoid complication of surgical removal of third molars Retention of treated cases  for correction of incisors relationship: No retention is needed because the incisor will maintain their new position by normal overjet and overbite and normal incisal inclination  for buccal cross bite: No retention is needed if proper interdigitation of buccal segment is obtained For individual teeth position, rotation: Hawley retainer can be used For anterior posterior skeletal relationship: FR III or reversed activator that used in treatment can be used or construction of Hawley retainers. As a general role in class III cases retention needs longer periods than other malocclusion Effect of growth in class III treatment It is generally considered that growth changes in class III are more likely to make the condition worse than better. Clinical experience suggests that the mandible tends to become more Prognathic than maxilla due to growth changes Knott 1973 has reported that mandibular growth relative to cranial base progress after 17 years of age, so that, must accept failure in some cases of mandibular prognathism particularly in boys whose dramatic growth changes during and after treatment may represent serious problem in clinical orthodontic. The sex difference is due to the retarded pubertal growth spurt in males relative to females Class III Malocclusion Class III Malocclusion Dr. Mohammed Alruby Dr. Mohammed Alruby