Discussion
Age-Related Changes in the Growth of Maxilla and Mandible
Postnatal growth of the maxilla occurs by apposition of bone at the sutures, which
connects the maxilla to the cranial base and surface remodeling. Maxilla grows downward
and forward up to the age of 6 by forward displacement of maxilla from cranial base.
At 7 years of age, cranial base growth stops and sutural growth begins, bringing the
maxilla forward.
The maxillary prominence angle decreases progressively throughout childhood and increases
after adolescence. The intersphenoidal synchondrosis ossifies immediately before birth
and the ethmoidal synchondrosis ossifies 7 years after birth, the growth of the central
area of the cranium completes in the early stages of life.[4]
At birth, the transverse and anteroposterior diameters of the bone are much greater
than the vertical. The frontal process is well-marked and the body of the bone consists
of little more than the alveolar process. The teeth sockets reach almost to the floor
of the orbit. The maxillary sinus presents the appearance of a furrow on the lateral
wall of the nose. In the adulthood, the vertical diameter is the greatest and no much
changes occur. In old age, the bone reverts in some measure to the infantile condition
as its height is diminished. After the loss of the teeth, the alveolar process is
absorbed and the lower part of the bone is contracted and reduced in thickness.
The steady growth of maxilla is seen until 5 years of age, where 85% of adult size
is achieved. Page reported that at the age of 8, up to 90% of maxillary growth is
attained.[5] Anteroposterior palatal growth occurs around 7 years of age. Vault depth is also
attained by 7 years of age. Post 8 years of age, the decline in growth is seen that
completes by approximately 11 years of age. Minimal growth changes in the maxilla
are seen following 11 years of age. This is one of the major factors to be considered
for maxillary protraction. The closure of midpalatal suture usually occurs at a certain
age, that is, 11 to 13 years in girls and 14 to 16 years in boys. Fusion of maxillary
sutures is completed at the age of 14 to 15 in females and 15 to 16 in males.[6]
Growth of the mandible occurs by endochondral growth mechanism at each end and intramembranous
growth between the bones. The body of the mandible grows by periosteal apposition
of bone on the posterior surface of the ramus. Ramus grows higher by endochondral
replacement at condyle accompanied by surface remodeling.
The condyle is the primary growth center that contributes to the growth of the mandible.
The condylar cartilage is capable of regional adaptive growth. Buschang et al reported
that maximum growth in the condylar region is seen during the pubertal period as compared
with prepubertal period.[6] Decrease in condylar growth occurs during early childhood. Growth of the mandible
continues up to 16 to 20 years, followed by which there is a decline. At birth, the
body of the bone is a mere shell, containing the sockets of the two incisors, the
canine, and the two deciduous molar teeth, imperfectly partitioned off from one another.
The mandibular canal is of large size, and runs near the lower border of the bone;
the mental foramen opens beneath the socket of the first deciduous molar tooth. The
angle is obtuse (175 degrees), and the condyloid portion is nearly in line with the
body. The coronoid process is of comparatively large size, and projects above the
level of the condyle. During childhood, the two segments of the bone become joined
at the symphysis, from below upward, in the first year; but a trace of separation
may be visible in the beginning of the second year, near the alveolar margin. The
body becomes elongated in its whole length, but more especially behind the mental
foramen, to provide space for the three additional teeth developed in this part. The
depth of the body increases owing to increased growth of the alveolar part, to afford
room for the roots of the teeth. The angle becomes less obtuse, owing to the separation
of the jaws by the teeth; about the fourth year it is 140 degrees. During adulthood,
after the eruption of permanent teeth the mental foramen lies midway between the upper
and lower borders of the bone. Growth of the rami takes place posteriorly and vertically
by the process of remodeling. Posterior growth accommodates the eruption of permanent
molars and reduces the angle of mandible to almost 110 to 115 degrees. Vertical growth
allows the condylar process to lie higher than the coronoid process. During old age,
teeth fall out and the alveolar border is absorbed so that the height of the body
is markedly reduced. The mental foramen and the mandibular canal are close to the
alveolar border. The angle again becomes obtuse approximately 140 degrees because
the ramus is oblique. Mandibular growth was found to be statistically significant
for the age periods of 16 to 18 years and 18 to 20 years. Growth from 16 to 18 years
was greater than that from 18 to 20 years. Mandibular growth was found to involve
an upward and forward rotation, a result of posterior vertical growth exceeding anterior
vertical growth.[7] Hence, mandibular growth continues for a longer period even if the treatment is
initiated during an early age.[8]
Management of Skeletal Class III Malocclusion During
Primary Dentition Period
Intervention at an early stage, such as the primary dentition period, has been recommended
by various authors[9]
[10] The goals of early intervention are to prevent progressive, irreversible soft-tissue
or bony changes, improve skeletal discrepancies, provide a favorable environment for
normal growth, improve occlusal function, enhance and shorten phase II comprehensive
treatment, and provide pleasing facial aesthetic, thus improving the psychosocial
development of the child.[11]
Turpin et al have reported positive and negative factors for early correction of skeletal
class III malocclusion.[12]
|
TURPIN et al (1981)
|
|
Positive factors:
|
Negative factors:
|
|
1. Good facial esthetics
|
1. Poor facial esthetics
|
|
2. Mild skeletal disharmony
|
2. Severe skeletal disharmony
|
|
3. No familial prognathism
|
3. Growth complete
|
|
4. Anterior posterior functional shift
|
|
|
5. Convergent facial types
|
|
Proclination of mandibular incisors and retroclination of maxillary incisors result
in anterior posture of mandible due to incisal interferences. This condition is called
pseudoclass III malocclusion. Forward positioning of mandible can express the genes
associated with mandibular prognathism, leading to true skeletal class III malocclusion.
This is one of the major concerns in deciduous dentition. When such conditions are
identified during primary dentition, treatment must be initiated to prevent worsening
of the condition.[13]
[14] Guyer et al stated that in children with anterior crossbite and reverse deep bite,
intervention during primary dentition is beneficial.[15]
According to Ngan et al, promising results can be achieved for maxillary retrusion
at an early age, if untreated can worsen later. However, mandibular excess or vertical
excess are poor candidates for early treatment as peak mandibular growth occurs during
pubertal period. Relapse of such conditions is also high during prepubertal or pubertal
period.[16]
Sargod et al, in his case report, used reverse twin block appliance in two children
in the age group of 5 years and achieved positive results. He stated that it is important
to remove the interlocking of the anterior teeth for unrestricted growth of maxilla
and to guide the mandible to the correct position.[17]
Sadia et al conducted a study, in which she compared the use of facemask therapy in
3 to 6, 6 to 9, and 9 to 12 age group, better results were seen in the age group of
3 to 6 years.[18]
Kapust et al compared the treatment effect of facemask appliance in various age groups
and concluded that the effect was much better in the age group of 4 to 7 years.[19] Franchi et al, in his study, stated that when treatment is initiated with facemask
appliance, maximum results are seen during early or mixed dentition period.[20] Bedolla-Gaxiola et al conducted a study, where she used facemask appliance during
primary dentition period (5 years), acceptable results were achieved.[21]
Hence, in case of maxillary retrusion acceptable results can be achieved during primary
dentition period using appliances such as facemask. Early treatment is beneficial
for maxillary protraction and palatal expansion considering the age at which maxillary
growth occurs.
Early treatment can also decrease the psychological burden in these children.
Habits, position of the mandible, and abnormal muscular forces can be prevented when
treatment is initiated during primary dentition period as compared with mixed or permanent
dentition period.
Chin cup therapy has been advised in the age group of 4 to 14 years.[22]
[23] Sakamoto , in his study used chin cup appliance in the age group of 3 to 12 years,
concluded stating that the treatment effect was much higher in younger age group.[24]
However, conflicting results are stated by various authors in case of mandibular prognathism.
Some authors believed in two to three phases of treatment, in which mandibular prognathism
is corrected during the second or third phase.
Regarding the skeletal changes during deciduous dentition, authors have reported conflicting
results. According to a study done by Kajiyama et al, increased skeletal changes are
seen during primary dentition period as compared with mixed dentition period.[25] But Kapust et al have reported less orthopaedic changes seen in younger age group
as compared with older age group.[19] Gnanashanmugam and Kannan stated that currently there are no evidence present to
suggest the reduction or elimination of future treatment following early management
of class III malocclusion.[26]
|
Sl. no.
|
Title of the study
|
Age
|
Parameters
|
Results
|
|
1.
|
Early class III management in deciduous dentition using reverse twin block[17]
|
5 years
|
Case 1: overjet, profile
|
Case 1: Improvement in profile, positive overjet was achieved, anterior crossbite
was corrected
|
|
2.
|
Sagittal changes after maxillary protraction with expansion in class III patients
in the primary, mixed, and late mixed dentitions: a longitudinal retrospective study[18]
|
Group 1: 3–6
Group 2: 6–9
Group 3: 9–12
|
SNA, SNB, maxillary depth, facial convexity angle
|
Greater significant changes were seen in patients treated in the primary and mixed
dentition phases. Females showed highly significant changes in most linear and angular
measurements between the ages of 3 and 6 years (p < 0.0001) compared with males (p < 0.05) at the same age. Significant changes were seen in the angle between the anterior
part of the maxilla and the base of the skull (SNA), the maxillary depth, and the
facial convexity angles, being more active in females than males. In contrast, the
angle between the anterior part of the mandible and the base of the skull (SNB) showed
no significant changes in all age groups, with the exception of males between 3 and
6 years
|
|
3.
|
Cephalometric effects of facemask/expansion therapy in class III children: a comparison
of three age groups[19]
|
4–13 years
|
Skeletal, dental and soft tissue analysis
|
Skeletal change was primarily a result of anterior and
vertical movement of the maxillae. Mandibular position was directed in a downward
and backward vector and soft tissue effects resulted in a more
convex profile. Greater differences were observed in apical base change (ABCH) and
total molar correction (6/6) in the younger age groups
|
|
4.
|
Quick correction of a skeletal class III malocclusion in primary dentition with facemask
plus rapid maxillary expansion therapy[20]
|
5 years
|
Overjet, SNA, SNB, articulare, saddle, gonial angle
|
Clockwise rotation of the mandible, a positive overjet of 3 mm, a correct overbite,
a canine Class I relationship, and a bilateral flush terminal plane
|
|
5.
|
Effective timing for the application of orthopedic force in the skeletal class III
malocclusion[21]
|
3–12 years
|
A-B difference, crossbite
|
Correction of crossbite was achieved. The final values showed more improvement in
the younger age group in the group with milder disharmony before treatment
|
Mixed Dentition Period
The transition from deciduous to mixed dentition period occurs at the age of around
6 years when the permanent lower central incisor erupts. First phase of transition
occurs when the incisors and molars erupt to the cavity, termed as early mixed dentition
period at the age of 7 to 10 years. The second transition period occurs when the canine,
premolars, and second molars erupt, which is termed as late mixed dentition period
around the age of 11 to 12 years. Significant changes occur in the craniofacial region
during this transition period that can be utilized for orthodontic therapy. Hence,
we can divide the management of class III malocclusion in the mixed dentition period
to early and late mixed dentition period.
Early Mixed Dentition Period
Ideal age for maxillary protraction as mentioned by various authors is during the
early mixed dentition period. This is because the main aim of appliances such as facemask
is to enhance forward displacement of maxilla by sutural growth. Melsen and Melsen
in her histological study reported that the mid palatine suture is broad and smooth
during infantile period (8–10 years), which then become squamous and overlapping during
late adolescent period. Treatment initiated before the age of 8, after eruption of
central incisors, is the most appropriate time as the sutures are broad and flat.[27] Therapy induced during early mixed dentition is reported to show more favorable
skeletal changes as compared with late mixed dentition period.
Baccetti et al conducted a study where facemask appliance was used in two groups,
early and late mixed dentition period. Result showed that the treatment initiated
during early mixed dentition period showed better result as compared with late mixed
dentition period. More upward and forward direction of condylar growth was seen in
early mixed dentition group.[28] In another study, he reported more favorable changes in the craniofacial skeleton
seen in early mixed dentition compared with late mixed dentition.[20]
Franchi et al reported significant favorable changes in early mixed dentition stage
as compared with late mixed dentition stage. Favorable postpubertal changes were seen
in both maxillary and mandibular structures in the early treatment group. In late
treatment group, changes were mainly limited to mandible, by restriction of mandibular
growth.[29]
Other studies done by Mandall et al, Westwood et al, and Ngan et al also showed significant
maxillary protraction during early mixed dentition period.[8]
[30]
[31]
According to a systematic review and meta-analysis by Lin et al, maxillary protraction
devices during early mixed dentition showed short-term significant skeletal and dental
changes; however, during long-term follow-up, relapse of some skeletal and dental
parameters was noted. Hence, long-term study is required for a definitive conclusion
of stability of maxillary protraction.[32]
Sharma et al reported two cases where significant skeletal changes were achieved following
the use of TTBA in 7-year-old children. He stated that less iatrogenic tooth damage
like root resorption, decalcification, and trauma is seen when early treatment is
initiated. Several other authors also reported successful outcome following TTBA during
early mixed dentition period.[33]
[34]
[35] Atalay and Tortop conducted a study where modified TTBA was used in the early and
late treatment group. Significant skeletal and dental changes were seen in both the
groups. Maxillary protraction was evidently noticed in both the group; however, reduction
in SNB angle was more apparent in the early group as compared with late group[36]
Reverse twin block appliance has been reported to cause mandibular retrusion in early
mixed dentition period. Mittal et al in his case report showed successful correction
of anterior crossbite in an 8-year-old child.[37] Kidner et al conducted a study in the age group of 7 to 10 years using reverse twin
block appliance and concluded that significant changes were seen during early mixed
dentition period.[38] However, Shriranjani et al in the systematic review stated that the available evidence
for correction of skeletal class III malocclusion using reverse twin block appliance
is scarce.[39]
Saveen et al reported acceptable treatment outcome following the use of Frankel III
appliance in a 9-year-old child. Restriction of mandibular growth and protraction
of maxilla were achieved.[40]
Sugawara et al conducted a study on monozygotic twins; in one child two phase treatment
was approached, that is, early correction of crossbite followed by fixed appliance
therapy at a later stage; in the other child, single phase treatment was initiated
using fixed appliance therapy. There was a significant improvement in the first child;
however, during pubertal period relapse was seen with similar profile in both the
children. Even though early treatment reduces the intensity of fixed therapy at the
later stage, no much differences were seen during pubertal period.[41]
Al-Khalifa et al reported significant effect following the use of chin cup in the
age group of 7 to 9 years.[42]
Study conducted by Alarcón et al in the age group of 8.5 years using chin cup appliance
concluded stating wide modification of the mandibular shape (more rectangular mandibular
configuration, forward condyle orientation, gonial area compression, and symphysis
narrowing).[43]
Deguchi and McNamara conducted a study in 9-year-old children, reporting reduction
in mandibular growth increments following chin cup appliance therapy.[44]
Akin et al, Lin et al, Y.L et al showed similar positive results following chin cup
therapy. Majority of the studies done on chin cup appliance are during mixed dentition
period.[45]
[46]
[47]
Ideal age group for appliances such as chin cup, which restrict the growth of mandible,
was reported to be before 8 years of age.
|
Sl. no.
|
Title of the study
|
Age
|
Parameters
|
Results
|
|
1.
|
Treatment and posttreatment craniofacial changes after rapid maxillary expansion and
facemask therapy[20]
|
Group 1: Early mixed dentition period
Group 2: Late mixed dentition period
|
Linear measurement for the assessment of sagittal relationship, mandibular dimension,
angular measurement for cranial base angle, angular measurement to assess condylar
angulation
|
Significant increase in the sagittal growth of maxilla can be obtained at when treatment
is performed at early mixed dentition period
Backward rotation of mandible with increase in anterior facial height is seen when
the treatment is initiated during late mixed dentition period
Class III malocclusion in the early mixed dentition appears to induce more favorable
overall craniofacial changes than treatment in the late mixed dentition
|
|
2.
|
Skeletal effects of early treatment of class III malocclusion with maxillary expansion
and facemask therapy[28]
|
Group 1: Early mixed dentition period
Group 2: Late mixed dentition period
|
Linear measurement for the assessment of sagittal relationship, mandibular dimension,
angular measurement for cranial base angle, angular measurement to assess condylar
angulation
|
Maxillary expansion and facemask therapy was more effective in early mixed dentition
period. Significant maxillary protraction was seen in early mixed dentition period.
Smaller increments in total mandibular length associated with more upward and forward
direction of condylar growth were recorded only in the early-treatment group
|
|
3.
|
Postpubertal assessment of treatment timing for maxillary expansion and protraction
therapy followed by fixed appliances[29]
|
Group 1: Early mixed dentition period
Group 2: Late mixed dentition period
|
Skeletal changes, maxillary dental, mandibular dental, and interdental changes
|
Orthopaedic treatment of class III malocclusion was more effective when it was initiated
at an early developmental phase of the dentition rather than during later stages
Early treatment produced significant favorable postpubertal modifications in both
maxillary and mandibular structures, whereas late treatment induced only a significant
restriction of mandibular growth
|
|
4.
|
Stability of maxillary protraction therapy in children with class III malocclusion:
a systematic review and meta-analysis[32]
|
|
SNA, SNB, ANB, mandibular plane angle, overjet, and lower incisor angle
|
Maxillary protraction can be a short-term effective therapy and might improve sagittal
skeletal and dental relationships in the medium term. But some skeletal and dental
variables showed significant relapse during the follow-up period. Long-term studies
are still required to further evaluate its skeletal benefits
|
|
5.
|
Early treatment of class III malocclusion with modified tandem traction bow appliance
and a brief literature review[33]
|
7 years
|
SNA, SNB, ANB, Wits appraisal, midfacial length, mandibular length, maxillomandibular,
differential, Steiners analysis, IMPA, interincisal angle, Y axis
|
The correction in the cross bite was achieved in six to seven months
Children's compliance and acceptance for the appliance was good. Follow-up of 2 years
and 1 year showed no relapse
|
|
6.
|
Dentofacial effects of a modified tandem traction bow appliance[36]
|
Group 1: Early treatment (8 years)
Group 2: Late treatment (11 years)
|
Skeletal, dental analysis (Linear and angular measurements)
|
Maxillary protraction was evidently noticed in both the group; however, reduction
in SNB angle was more apparent in the early group as compared with late group
|
|
7.
|
Reverse twin block for interceptive management of developing class III malocclusion[37]
|
Case report1: 11 years
Case report 2: 8 years
|
SNA, SNB, ANB, SND, Witts appraisal, SN-MP, UAFH, LAFH, U1-SN, IMPA, mandibular length
|
Anterior crossbite was corrected, and there was a marked improvement in facial appearance
of the children. RTB can be a viable and effective functional appliance treatment
modality for early management of developing class III malocclusion
|
|
9.
|
Craniofacial adaptations induced by chin cup therapy in class III patients[44]
|
9 years
|
Investigation of the orthopaedic effect of CC in the posterior displacement of the
mandible and the glenoid fossa.
|
Significantly decreased gonial angle, less incremental increase in mandibular length
(Gn-Cd), posterior movement of points B and Pg, not increased anterior facial height
|
IAMP, Incisor Mandibular Plane Angle; LAFH, Lower Anterior Facial Height; SN-MP, Sella
Nasion-Mandibular Plane Angle; RTB, Reverse Twin Block; UAFH, Upper Anterior Facial
Height.
Late Mixed Dentition Period
Treatment effect of skeletal class III malocclusion during late mixed dentition period
is a controversial topic. Most of the authors recommend treatment during early mixed
dentition rather than late mixed dentition period. However, there are studies stating
the positive effect of class III treatment even during late mixed dentition period.
Battagel and Orton reported that positive results can be achieved following facemask
therapy in late mixed dentition period with minimum 2 years of retention. Mandibular
growth was redirected, but not reduced during the treatment. Post retention growth
acceleration can be minimized following facemask therapy during late mixed dentition
period.[48]
In a case report by Pattanaik and Mishra, a 12-year-old female child was treated with
facemask and rapid maxillary expansion device. Acceptable results were achieved.[49]
Even though facemask has been indicated during deciduous or early mixed dentition
period, positive results can be achieved even during late mixed dentition period.
Rajasekaran and Abdulla used Frankel III appliance in an 11-year-old girl; optimum
results were achieved in a follow-up period of approximately 2 years.[50]
Fareen et al conducted a study in which a combination of reverse twin block appliance
and reverse pull facemask was used in early and late mixed dentition group. Significant
changes were seen in both the group; however, more favorable craniofacial changes
were seen particularly in late mixed dentition group.[51]
Singh et al used chin cup therapy during late mixed dentition period and redirected
mandibular growth was achieved.[52]
Maxillary protraction using bone anchorage and class III elastics is reported to be
more effective during late mixed and permanent dentition period.[53]
Van Hevele et al conducted a study on 218 patients with mean age of 11.4 years using
bone anchorage maxillary protraction device (BAMP). He reported a success rate of
approximately 93.6%.[54]
Use of BAMP during late mixed dentition period was supported by various authors.[55]
[56]
Feng et al in a systematic review titled, effectiveness of TAD anchored maxillary
protraction in late mixed dentition period, concluded stating that TAD anchored maxillary
protraction has greater protraction effect.[57]
Barrett et al in his study used chin cup appliance and reported limited class III
correction with light force chin cup (fewer than 50% of the patients) mostly by dentoalveolar
(uprighting of mandibular incisors) rather than orthopaedic changes during early mixed
dentition period.[22]
|
Sl. no.
|
Title of the study
|
Age
|
Parameters
|
Results
|
|
1.
|
Class III malocclusion: the post-retention findings following a non-extraction treatment
approach[48]
|
12.9 years
|
Skeletal, dental, soft tissue analysis
|
Overjet correction was achieved by a combination of upper and lower incisor movement
with no alteration in overbite. This was accompanied by a downward and backward repositioning
of the mandible, redirecting, rather than restricting mandibular growth
|
|
2.
|
Treatment of Class III with facemask therapy[49]
|
12 years
|
Sagittal, dentoalveolar, and vertical cephalometric measurements
|
The patient displayed a bilateral Class I canine and a Class I molar relationship.
The SNA angle had increased while SNB decreased resulting in a normal jaw relationship
(ANB = 2 degrees) Normal overbite (1 mm) and overjet (3 mm) were achieved, and the
midlines were centered. Vertical skeletal measurements remained near-constant
|
|
3.
|
Interception of skeletal Class 3 malocclusion with Frankle 3 appliance in late Mixed
dentition: a case report[50]
|
11 years
|
Skeletal and dental analysis
|
This study demonstrated the achievement of optimal results, and the stability of the
correction of a functional Class III malocclusion treated with a Frankle 3 and followed
by corrective orthodontics
|
|
4.
|
Treatment effects of reverse twin-block and reverse pull facemask on craniofacial
morphology in early and late mixed dentition children[51]
|
Early mixed dentition: 8–9 years
Late mixed dentition: 10 -11 years
|
Ricketts analysis
|
RPFM revealed more favorable craniofacial changes than RTB, particularly in the late
mixed dentition stag
|
|
5.
|
Bone-anchored maxillary protraction to correct a class III skeletal relationship:
a multicenter retrospective analysis of 218 patients[54]
|
11.4 years
|
SNA, SNB, ANB, Wits analysis
|
Miniplate failure was six times higher in the maxilla and occurred more in younger
patients
|
|
6.
|
Treatment effects of the light-force chincup[22]
|
8 years
|
Skeletal, dental analysis (linear and angular measurements)
|
Fewer than 50% of the subjects treated with the chin cup had favorable clinical outcomes.
Correction of the initial Class III malocclusion occurred through significant dentoalveolar
changes. The light-force chin cup did not produce orthopaedic changes in the mandible.
|
Permanent Dentition Period
Maxillary protraction devices are less effective during permanent dentition period
as compared with primary and mixed dentition period.
However, some authors have reported cases with acceptable results during prepubertal
period.
Jackson and Kravitz al used facemask appliance with maxillary expansion to correct
skeletal class III malocclusion in an adult patient, skeletal change as a result of
anterior and vertical movement of the maxilla, significant changes in mandibular position,
and downward and backward movement of the chin was noted. However, there was increase
in vertical dimension of the face.[58]
Jatol-Tekade et al used TTBA in a 12-year-old child; optimal outcomes were achieved.[59]
In a case report by Singh et al, a 12-year-old girl with permanent dentition was treated
using reverse twin block and fixed mechanotherapy with a 3-year follow-up period.
Favorable environment for unrestricted growth of maxilla, at the same time redirecting
mandible to a clockwise rotation along with correction of incisal relationship, was
achieved.[60]
Bone anchorage maxillary protraction can be used during permanent dentition period.
Successful outcomes have been achieved by using this appliance.
According to Cordasco et al, miniplate placement on the anterior surface of the maxilla
is invasive and bone maturity is not adequate until around age 11; hence, it can be
used during permanent dentition period.[61]
In a study by Kuroda et al, extraction of four premolars, rapid palatal expansion,
and combination occipital and vertical-pull chin cup over a 2-year period led to good
results at age 16, with minimal dental or skeletal relapse at age 18 years, 5 months.[62] In adulthood, not much treatment options are present, other than surgical intervention
and camouflage treatment.
|
Sl. no.
|
Title of the study
|
Age
|
Parameters
|
Results
|
|
1.
|
Expansion/facemask treatment of an adult class III malocclusion[58]
|
19 years
|
Skeletal and dental cephalometric measurements
|
Skeletal change was primarily a result of anterior and vertical movement of the maxilla
Significant changes in mandibular position also contributed to the class III correction
|
|
2.
|
Skeletal class III correction in permanent dentition using reverse twin block appliance
and fixed mechanotherapy[60]
|
12 years
|
Skeletal and dental cephalometric measurements
|
Redirected the mandibular growth to a clockwise direction
Corrected the incisal relationship
|
|
3.
|
Chincup therapy for a young woman with anterior displacement and obtuse angle of the
mandible in Class I malocclusion[62]
|
16 years
|
Skeletal cephalometric analysis of maxilla, mandible and cranial base
|
Closure of the gonial angle that induced backward rotation of the mandible
|
Conclusion
Management of skeletal class III malocclusion is still a controversial topic, especially
the treatment timing.
According to Campbell, goals of early interception of class III malocclusions are
as follows:
-
help provide a more favorable environment for normal growth
-
achieve as much relative maxillary advancement as possible
-
To improve occlusal relationships
-
To improve facial esthetics for more normal psychosocial development[63]
Treatment timing is debatable as each group has its own benefits and drawbacks.
Accurate diagnosis and understanding of the individual growth pattern are very important
in determining the proper timing of class III treatment.
Optimal treatment timing for facemask therapy is in the deciduous or early mixed dentition
period.
Delaying appropriate treatment beyond the mixed dentition stage (10 years of age)
will limit the effectiveness of orthopaedic correction.
More importantly, treating a class III malocclusion in the late deciduous and early
mixed dentition stages has been shown to be more beneficial to the child as there
is improved maxillary orthopaedic correction combined with controlled mandibular growth
than when treatment is undertaken in the later childhood growth stages using reverse
twin block appliance.[17]
However, in case of BAMP, treatment is indicated to begin once bone maturity is attained,
which is during the late mixed or permanent dentition period.[18]
Chin cup therapy is primarily used to restrict the growth of mandible; majority of
the studies support the use of chin cup during early mixed dentition period.
Hence, a definite conclusion cannot be attained at the point. More studies with longer
follow-up are required to attain a definite conclusion.
