Age prediction based on skeletal morphology

Treatment plan for a child requires a complete diagnosis with monitoring of the skeleto-dental morphological changes during active period of growth. Growth modifications are done while the forces of growth are still at the peak of activity in a developing child. This study was undertaken on lateral cephalograms of 100 North Indian samples in the age group of 9-12 years consisting of 50 males and 50 females divided into normal occlusion and malocclusion groups, to predict and assess age by evaluating the skeleto-dental morphology in developing normal children having flush terminal plane molar relationship and children with developing class II pattern. It was concluded that based on measurements used in the study of dentofacial morphology, the age of a child could be statistically determined.

A biometric guide to prosthetic tooth positioning investigated in subjects with Class II division 2 incisor relationships

A biometric guide for positioning of the maxillary central incisors in complete dentures is the incisor-incisive papilla distance. This distance was compared in dentate subject with either Class I or Class II/2 incisor relations. Maxillary casts were orientated parallel to the occlusal plane on an xy table, connected to a movable vertical arm. The distance from the posterior edge of the papilla to the labial incisor surface was measured. Results showed a mean difference of 2 mm between the groups, significant at the P < or = 0.001 level, however this distance would not appear to invalidate the conventional biometric guideline of 10 mm.

Functional appliance treatment assessed using the PAR index

The aims of this study were, first, to determine in children with Class II, division 1 malocclusions treated with functional appliances if, according to the Peer Assessment Rating (PAR) Index, lower incisor proclination affects the assessment of treatment outcome; and, second, to evaluate the effectiveness of such treatment before and after adjustment for any lower incisor proclination. Fifty-one children (32M, 19F; age and gender matched; 10 to 13 years) were randomly assigned to either an untreated group, one treated with Fränkel function regulators or one treated with Harvold activators. Study casts were assessed at the start, and after 6, 12, and 18 months of treatment/observation. The inclination of the upper and lower incisors was measured on lateral cephalometric radiographs taken at the start and 18 months later. There was wide variation in treatment response. The PAR scores decreased by more than 30% in 33% of the Fränkel group and by 75% in the Harvold group. When the score was adjusted to remove the effects of lower incisor proclination on the overjet, the treatment outcomes were "worse/no different" in 66% and "improved" in 33%, in both groups. It was concluded that functional appliances be used only on selected cases.

Non-extraction tip-edge appliance management of a moderate Angle Class II division 1 malocclusion commenced in the late mixed dentition

This case presentation concerns the correction of a moderate Angle Class II division 1 malocclusion of a patient whose treatment began during the late mixed dentition. Owing to the need to preserve and improve the existing facial aesthetics, treatment was started with a non-extraction approach and, in order to exploit favourable dentofacial growth changes and to avoid the possibility of extraction of teeth, was timed to coincide with the patient's expected adolescent growth spurt. Fixed appliances only were used. Special consideration had to be made for the patient's fractured upper central incisor teeth. An aesthetically pleasing treatment outcome was achieved within the expected time frame for correction. The case shows the successful combination of typical Begg mechanotherapy used during the early stages of treatment and Tip-Edge rectangular archwire mechanotherapy as used for the later and finishing stages.

The effects of orthognathic surgery on pharyngeal airway dimensions and quality of sleep

Orthognathic surgery has been associated with airway narrowing and induction of sleep-related breathing disorders. Therefore, the pharyngeal airway dimensions of 32 orthognathic surgery cases were prospectively investigated, and the relationship between the surgery and sleep quality assessed. Digitized lateral cephalometric radiographs were used to compare oropharyngeal airway morphologies before and after surgery. Patients were assessed in two main surgical groups based on sagittal jaw relationship. A questionnaire was used to assess changes in daytime sleepiness. The mandibular surgery cases were also assessed by overnight domiciliary sleep monitoring. A significant decrease in the retrolingual airway dimension was found in all patients after mandibular setback surgery and a significant increase in this dimension after mandibular advancement. The questionnaire and sleep study revealed no significant changes in snoring incidence or apnoeic events after mandibular setback surgery. For the mandibular advancement group, a change in sleep quality was found, but only in cases with signs of a pre-existing sleep disorder.

Relapse in Angle Class II Division 1 Malocclusion treated by tandem mechanics without extraction of permanent teeth: A retrospective analysis

Ideal orthodontic treatment should achieve long-term stability of the occlusion. The mandibular incisor segment has been described as the segment that is most likely to exhibit relapse after treatment and retention. Therefore, relapse of this is a challenge that clinicians need to address. The purpose of this study is to evaluate the amount of relapse that may occur in Angle Class II Division 1 patients, treated orthodontically with tandem mechanics. All cases in this study were treated without extraction of permanent teeth, and the patients were followed for at least 2 years after the end of the retention phase of treatment. Six predictors were investigated at pretreatment, posttreatment, and postretention periods. A synopsis of this study shows the correction of lower incisor crowding as measured by the irregularity index was stable over 5.2 years of postretention follow-up; but longer follow-up time revealed increased relapse of incisor irregularity. Intermolar width increased during treatment and remained stable in the follow-up period. Overjet and overbite corrections and changes in the lower incisor to mandibular plane angle were also stable in the follow-up period. In addition, the amounts of overjet correction and loss of expansion of intercanine distance after treatment were associated with increased irregularity index in the follow-up period. It appears the discrepancies between this and previously published works are sufficiently dramatic that the whole question of treatment philosophy and long-term stability may need to be reevaluated.

A comparative study of skeletal and dental stability between rigid and wire fixation for mandibular advancement

This study examined the skeletal and dental stability after mandibular advancement surgery with rigid or wire fixation for up to 2 years after the surgery. Subjects for this multisite, prospective, randomized, clinical trial were assigned to receive rigid (n = 64) or wire (n = 63) fixation. The rigid cases received three 2-mm bicortical position screws bilaterally and elastics; the wire fixation subjects received inferior border wires and 6 weeks of skeletal maxillomandibular fixation with 24-gauge wires. Cephalometric films were obtained before surgery, and at 1 week, 8 weeks, 6 months, 1 year, and 2 years after surgery. Skeletal and dental changes were analyzed using the Johnston's analysis. Before surgery both groups were balanced with respect to linear and angular measurements of craniofacial morphology. Mean anterior advancement of the mandibular symphasis was 5.5 mm (SD, 3.2) in the rigid group and 5.6 mm (SD, 3.0) in the wire group. Two years after surgery, mandibular symphasis was unchanged in the rigid group, whereas the wire group had 26% of sagittal relapse. Dental compensation occurred to maintain the corrected occlusion, with the mandibular incisor moving forward in the wire group and posteriorly in the rigid group. However, at 2 years after surgery, when most subjects were without braces, the overjet and molar discrepancy had relapsed similarly in both groups.

Effects of a three-dimensional bimetric maxillary distalizing arch

This study aimed to investigate the dental effects of a three-dimensional (3D) bimetric maxillary distalizing arch. The Wilson rapid molar distalization appliance for Class II molar correction was used in 14 patients (10 girls and four boys with a mean age of 12.18 years). The open coil springs were activated with bent Omega stops and Class II intermaxillary elastics. The mandibular anchorage was gained by a 0.016 x 0.016 utility arch with a 3D lingual arch or a lip bumper with a standard lingual arch. The lateral cephalograms taken before and after treatment formed the material of the research. A Wilcoxon test was used to statistically evaluate the treatment effects. The results showed that the distal tipping of the maxillary first and second molars, and first and second premolars and canines were statistically significant. Significant distal movement occurred in all posterior and canine teeth. The maxillary first molar distalization was found to be 3.5 mm. The maxillary incisor showed significant proclination and protrusion. The decrease in overbite was found to be statistically significant. The mandibular plane angle significantly increased by a mean of 0.5 mm. In addition, significant soft tissue changes were observed.

Nonextraction treatment of a high-angle class II malocclusion: a case report

A Class II malocclusion in a growing patient with hyperdivergent skeletal pattern and excessive vertical facial height is presented. The malocclusion was treated following a nonextraction approach, by molar distalization in combination with a removable appliance with finger springs and a high-pull gear. The space gained was used to retract the premolars, canines, and incisors.

Treatment of a Class II Division 1 malocclusion with a severe unilateral lingual crossbite with combined orthodontic/orthognathic surgery

A 24-year-old woman had a Class II Division 1 malocclusion with a severe unilateral crossbite. The crossbite was due partially to the maxilla being much wider than the mandible, allowing the mandibular left canine and first and second premolars to overerupt, impinging on the palatal tissue in habitual occlusion. The maxillary left segment from the lateral incisor to the first molar also overerupted producing 2 planes of occlusion. The malocclusion was treated successfully with comprehensive orthodontics, combined with a 2 piece Lefort I osteotomy procedure, a 3 tooth mandibular segmental osteotomy procedure, and a bilateral sagittal split osteotomy procedure.

Analysis of the mandibular position in malocclusion patients

OBJECTIVE

To study the changes of condyle position and occlusion between centric jaw relation (CR) and maximum intercuspation (MI) positions.

METHODS

The power centric registration advocated by Roth was used to take centric relation bite registration for 50 patients (25 Angle Class I, and 25 Angle Class II). Diagnostic models were mounted and analyzed with Panadent articulator and condylar position indicator.

RESULTS

Nearly all patients had CR-MI difference in all three spatial planes. Seventy percent of the sagittal displacement was within 2.0 mm and 87% of the transverse displacement was within 1.0 mm. Movement of most of the condyles was posterior and inferior. Sixty-five percent of the initial contacts in CR occurred on the most posterior molar on one side. When the mandible moved from CR to MI, overbite deepened, overjet decreased, and molar relationship became mesialized. Correlation was found between some variables of condylar displacement and occlusion changes. No significant difference between Angle Class I and Angle Class II patients was observed in condylar position and occlusion changes.

CONCLUSION

The occlusion in centric jaw relation should be analyzed before treatment to reveal the disharmony between occlusion and jaw position.

Dentoalveolar and skeletal changes associated with the pendulum appliance

The purpose of the study was to examine the dentoalveolar and skeletal effects of the pendulum appliance in Class II patients at varying stages of dental development and with varying facial patterns (high, neutral, and low mandibular plane angles). Specifically, the amount and nature of the "distalization" of the maxillary first molars and the reciprocal effects on the anchoring maxillary first premolars and incisors were studied, as were skeletal changes in the sagittal and vertical dimensions of the face. Pretreatment and posttreatment cephalometric radiographs obtained from 13 practitioners were used to document the treatment of 101 patients (45 boys and 56 girls). The average maxillary first molar distalization was 5.7 mm, with a distal tipping of 10.6 degrees. The anchoring anterior teeth moved mesially, as indicated by the 1.8-mm anterior movement of the upper first premolars, with a mesial tipping of 1.5 degrees. The maxillary first molars intruded 0.7 mm, and the first premolars extruded 1.0 mm. Lower anterior facial height increased 2.2 mm; there was no significant difference in lower anterior facial height increase between patients of high, neutral, or low mandibular plane angles. In patients with erupted maxillary second molars, there was a slightly greater increase in lower anterior face height and in the mandibular plane angle and a slightly greater decrease in overbite in comparison to patients with unerupted second molars. Similar findings were observed in patients with second premolar anchorage versus those with second deciduous molar anchorage. The results of this study suggest that the pendulum appliance is effective in moving maxillary molars posteriorly during orthodontic treatment. For maximum maxillary first molar distalization with minimal increase in lower anterior facial height, this appliance is used most effectively in patients with deciduous maxillary second molars for anchorage and unerupted permanent maxillary second molars, although significant bite opening was not a concern in any patient in this study.

[Analysis and comparison of dental arch symmetry between different Angle's malocclusion categories and normal occlusion]

OBJECTIVE

To analyze and compare dental arch symmetry between different Angle's malocclusion categories and normal occlusion.

METHODS

300 subjects were divided into four different malocclusion groups and normal occlusion group. Data points representing the dental arches on the casts were precisely marked by YM-2115 three Dimension Measuring Machine. Arch forms were fitted with conic sections, and then dental arch symmetry was analyzed by rotation angle.

RESULTS

There were no absolute symmetric dental arch, and the direction of asymmetry was unsteady. In normal occlusion, dental arch was generally symmetric, but there was asymmetry in a very small degree. As to malocclusion, the frequency and degree of dental arch asymmetry were higher than that of normal occlusion, and the lower arch showed more asymmetry than the upper arch except ClassIII. The frequency of asymmetry in ClassII2 and ClassIII groups was higher than that in other malocclusion groups.

CONCLUSION

The frequency and degree of dental arch asymmetry were different in different malocclusion groups.

Dental and facial skeletal characteristics and growth of males and females with class II, division 1 malocclusion between the ages of 10 and 14 (revisited)-part I: characteristics of size, form, and position

The purpose of this study was to describe and analyze the craniofacial and dentofacial skeletal characteristics associated with Angle's Class II, Division 1 malocclusion. The material examined included 613 lateral head radiographs comprising 2 series: (1) 278 films of children with "normal" occlusion and (2) 335 films of children with Class II, Division 1 malocclusion. Each series was subdivided into 6 samples (3 female and 3 male; skeletal ages 10, 12, 14, [+/-6 months]), representing children with chronological ages ranging from 8.5 to 15.5 years. The radiographs were converted to computer-readable X and Y coordinate data and 52 linear, angular, and coordinate axis measurements were taken. Findings were visually verified by superimposing the computer-drawn composite plots of the Class II, Division 1 series over those of the normal series. In all 6 intergroup comparisons, it was found that: (1) the mandible and its dentition is similar to the controls in size, form, and position except for the position of the lower incisors in males; (2) the forehead (Gl), anteriorcranial base (Nas), maxilla (A) and dentition (molars and incisors) are protrusive (mesial positioned), with an increased frontal bone thickness at the level of the sinus, and a larger A-P maxilla, the palate of which is inclined superiorly at its anterior half; (3) no vertical dysplasia was evident; (4) the cranial base angle is larger, as are the anterior and posterior sections that compose it, but it is not related to mandibular position; (5) angular indexes of maxillary and mandibular position that included point Nasion are highly misleading indicators of maxillary and mandibular size and position. Visualized diagnosis via a composite norm based on age and sex might offer a more reliable alternative or supplement to the numeric reference standards now in use. Enlarged sinuses may contribute to the cause of Class II, Division 1 malocclusion.

A method for protrusive mandibular force measurement in children

With this new method, protrusive mandibular force was studied in a homogeneous group of 69 children with similar occlusions. Maximum protrusive force ranged from 18.5 to 160 N (mean +/- SD = 81.3+/-31.6 N). Maximum protrusive force was significantly higher in males (90.7+/-30.2 N) than females (66.6+/-28.6 N) while fatigue time was not significantly different between the two groups (70.6+/-38.5 s for males and 65.1+/-33.6 s for females). Although protrusive force was stable in each session, it varied considerably between different experimental days within the same individual. No statistically significant correlation was found between maximum protrusive force and age, skeletal maturity, height, weight, overjet, maxillomandibular relation, facial height, facial widths or facial proportions.

[The craniofacial architectural factors predisposing to a skeletal Class II identified by Jean Delaire's architectural analysis]

The current state-of-the-art medical practice involves considering treatment both in terms of symptomatology and etiology. In the case of dento-facial deformities, treatment and prognosis must deal both with constitutional and functional anomalies. Most accurate diagnosis can be achieved using Jean Delaire's architectural cephalometric analysis. We illustrate the usefulness of this system using examples of class II skeletal malocclusions. Class II cranial malocclusion factors appear to be difficult to treat successfully. Maxillary and mandibular functional and constitutional anomalies are described. Functional deformities such as anterior rotation of the maxilla or posterior rotation of the mandibular ramus, can be successfully treated with early orthopedic care. Constitutional anomalies, such as excess length of the premaxilla or maxillary vertical excess, should frequently be treated in a combined orthodontic-surgical sequence as orthopedic care alone is ineffective. This explains the usefulness of Jean Delaire's architectural approach to obtain stable results in the treatment of maxillo-mandibular deformities.

Surgical versus orthodontic correction for Class II patients: age and severity in treatment planning and treatment outcome

Treatment options for Class II malocclusion include orthognathic surgery. Treatment choices are particularly difficult for young patients because of the uncertainty regarding future growth. Surgical treatment has generally been considered necessary for older patients with more severe Class II problems. The treatment records of more than 500 patients with Class II malocclusion were reviewed. Patients were grouped according to their initial treatment plan (surgery or orthodontics) and treatment outcome (overjet [OJ] reduced to < 4 mm or not). Discriminant function analyses using data from the patient's pretreatment cephalogram were used to determine whether age, in combination with malocclusion severity, could predict the choice of treatment, and whether a simple set of pretreatment variables could predict the success or failure of OJ reduction. The derived equations were tested in a similar group of growing Class II children. Although the data showed clinicians use patient's age in determining treatment choice, age did not seem to be associated with treatment outcome. The majority of the variability that determined the success or failure of OJ reduction was not explained by patient's age or malocclusion severity. These findings suggest other factors, including psychosocial variables, need to be explored if we are to gain a better understanding of why treatments succeed or fail.

Class II malocclusion correction: an American board of orthodontics case

A Class II open bite malocclusion with a narrowed maxilla, an increased lower anterior facial height, and a tooth size discrepancy are presented. The malocclusion was treated nonextraction in 2 phases. The mixed dentition phase of treatment was maxillary molar uprighting followed by a bonded rapid palatal expander. The vertical dimension was managed with a vertical pull chincup. The full appliance phase included buildups of the maxillary lateral incisors and mechanics to control lower incisor position.

Evaluation of apical root resorption following extraction therapy in subjects with Class I and Class II malocclusions

The purpose of this study was to determine the amount of root resorption during orthodontic treatment, and to examine the relationship between tooth movement and apical root resorption. Twenty-seven Class I and 27 Class II patients treated with edgewise mechanics following first premolar extractions were selected. The following measurements were made on the pre- and post-treatment cephalograms: upper central incisor to palatal plane distance, the inclination of upper central incisor to the FH and AP planes, the perpendicular distances from the incisor tip to the AP and PTV planes, and incisor apex to PTV. The amount of apical root resorption of the maxillary central incisors was determined for each patient by subtracting the post-treatment tooth length from the pre-treatment tooth length measured directly on cephalograms. Intra-group differences were evaluated by the Student's t-test and inter-group differences by the Mann-Whitney U-test. For correlations the Pearson correlation coefficient was used. The results show that there was a mean of approximately 1 mm (P < 0.01) of apical root shortening in Class I patients, but in Class II division I subjects the mean root resorption was more than 2 mm (P < 0.001). The inter-group differences were statistically significant. No significant correlations were found between the amount of apical root resorption and tooth inclination, or the duration of active treatment.

A cephalometric and tomographic evaluation of Herbst treatment in the mixed dentition

This study describes combined treatment and posttreatment effects for patients treated with the Herbst appliance in the mixed dentition followed by retention with a prefabricated positioner. The sample included 24 female and 16 male patients with Class II malocclusions. Posttreatment lateral cephalograms were taken an average of 17 months after Herbst removal, when the patients presented for phase II comprehensive orthodontics. The cumulative treatment and retention effects were compared with a sample of untreated Class II controls matched for age, sex, and mandibular plane angle. The overjet and molar relationship were corrected by 3. 4 and 3.3 mm, respectively. A headgear effect of Herbst therapy was observed, as anterior maxillary displacement was reduced by 1.2 mm. Condylar growth was redirected to produce 2.0 mm greater posterior growth in the treatment group. These effects produced significantly greater decreases in SNA (0.8 degrees ) and ANB (1.4 degrees ), and a tendency toward an increase in SNB (0.5 degrees ) Mandibular orthopedic effects resulted in an increase in anterior facial height (1.6 mm) and inferior displacement of the chin. Minimal changes in the displacement of condylion in relation to stable cranial base structures suggest that glenoid fossa displacement does not contribute in a clinically significant way to Class II correction. Pretreatment, immediate posttreatment, and postretention corrected temporomandibular joint tomograms demonstrated a tendency for the condyle to be slightly forward (0.2 mm) at the end of treatment and then to fall back after treatment. Statistically significant joint space changes were limited to the posttreatment period. We conclude that Herbst treatment in the mixed dentition, in combination with retention, produces significant long-term improvements in dental and skeletal relationships as a result of dentoalveolar changes and orthopedic effects in both jaws.

Dental asymmetry in temporomandibular disorders

In our previous study, it was reported that facial asymmetry due to mandibular lateral displacement (MLD) was significant in patients with temporomandibular disorders (TMD). In this study, dental asymmetry in TMD patients was investigated by means of PA cephalogram and study model. Lateral deviation of the midline of the mandibular occlusal table (PA-mid) and right-left difference of the molar relationship (Molar-Diff.) were examined, and their relationship with MLD was studied. PA-mid and Molar-Diff. were significantly correlated with MLD. In most cases, displaced side of the midline of the lower occlusal table was coincident with that of the mandibular skeletal midline. These results suggest that in TMD patients asymmetries in occlusal relationship of the midline of the mandibular teeth and molars were mainly due to a mandibular skeletal asymmetry and not merely due to a dental malposition on the alveolar basal bone. Many cases had a more distal occlusal relationship of the first molar on mandibular displaced side compared with that on the opposite side. A high incidence of Class II relationship was found (61.8% as a whole) and more remarkable on the mandibular displaced side. Midline discrepancy and right-left difference of the molar relationship seem to be important occlusal characteristics in patients with TMD.

Severe high Angle Class II Division 1 malocclusion with vertical maxillary excess and gummy smile: a case report

Severe Class II Division 1 malocclusion with vertical maxillary excess and gummy smiles can be treated in several ways. Early orthodontic treatment with vertical control may decrease the malocclusion as well as improve the appearance. In severe cases, orthognathic surgery might be the optimal solution. The following case report describes a patient with a severe gummy smile, where the final esthetic improvement was achieved by using a periodontal procedure after orthodontic treatment.

[An eight-factor analysis of early skeletal Class II malocclusion using Fränkel appliance]

OBJECTIVE

To investigate the change of eight-factor after Fränkel appliance treatment in skeletal class II malocclusions.

METHODS

X-ray cephalometric film.

RESULTS

Fränkel appliance can be used to enhance the growth of ramus (Factor 2) and body (Factor 1) of the mandible, decrease the angle of cranial base (Factor 8) and made the maxilla rotate (Factor 4) anteriorly, which were benefit to the treatment of class II malocclusion. However, neither the vertical (Factor 5) and sagittal (Factor 3) growth of maxilla nor the height of posterior alveolar bone (Factor 6) can be inhibited by use of Fränkel appliance.

CONCLUSION

Fränkel appliance is suitable to the treatment of class II patients with deficient mandible and almost normal maxilla, while Fränkel appliance would rather not be used for patients with overgrown maxilla or vertical growth pattern.

Nonsurgical correction of a class II malocclusion with a vertical growth tendency

Malocclusion, with a superimposed vertical growth tendency, is often difficult to treat without a combined surgical orthodontic approach. Certain situations, however, may preclude surgery as a treatment option. The following case report demonstrates the use of orthodontic mechanotherapy alone in successfully treating a patient that exhibited a Class II Division I malocclusion with a high mandibular plane angle and vertical growth tendency.