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Asymmetry in the face and dentition is a naturally occuring phenomenon. In most cases facial asymmetry can only be detected by comparing homologous parts of the face.

The etiology of asymmetry includes: a) Genetic or congenital malformations e.g. hemifacial microsomia and unilateral clefts of the lip and palate; b) Environmental factors, e.g. habits and trauma; c) Functional deviations, e.g. mandibular shifts as a result of tooth interferences.

Dental asymmetries and a variety of functional deviations can be treated orthodontically. On the other hand, significant structural facial asymmetries are not easily amenable to orthodontic treatment. These problems may require orthopedic correction during the growth period and/or surgical management at a later point.

Patient complaints and desires need to be addressed since they may vary from unrealistic expectations to a lack of concern even in the presence of large deviations. With mild dental, skeletal and soft tissue deviations the advisability of treatment should be carefully considered.

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Although the Jasper Jumper is becoming a widely accepted orthodontic appliance, no quantitative guidelines exist for therapy. The purpose of this investigation was to describe the orthopedic and orthodontic changes associated with Jasper Jumper therapy. A sample of 31 consecutively treated Class II patients was collected from three orthodontic practitioners who were using the same procedures and methods. Lateral cephalograms were taken immediately before appliance placement and immediately after appliance removal (mean interval of 0.4 years). The sample was case matched to untreated controls based on age, sex, and mandibular plane angle. The cephalograms were superimposed using anterior cranial base, maxillary, and mandibular reference structures to distinguish between growth/displacement and tooth movement. The results show that the majority of Class II correction was due to dental, rather than skeletal change. The maxilla underwent significant posterior displacement. The maxillary incisors retroclined and the maxillary molars tipped distally. Clockwise or backwards rotation was evident for the mandible. The mandibular incisors proclined significantly and the mandibular molars translated and tipped mesially.

Jasper Jumper therapy is a valuable procedure for the correction of Class II dental malocclusions. Like all other treatment modalities, there are both indications and contraindications for its use.

Abstract

Craniofacial characteristics in two groups of children were compared. In one group (n=22) the children had Angle Class II division 2 malocclusion combined with extreme deep bite. The other group (n=25) was composed of children with ideal occlusion. The mean ages of the children were 12.8 and 12.9 years respectively.

In the Class II-2 group the distance between gonion and B-point was underdeveloped, causing B-point to have a retruded position in relation to both A-point and cranial base. The Class II-2 children also had a retroclination of the symphysis, which gave the B-point a retruded position in relation to pogonion.

As for vertical dimensions, Class II-2 children had a smaller anterior lower facial height than normal. Furthermore, Class II-2 had a discrepancy between the maxillary incisal and molar heights, i.e. a slightly larger incisal height and a slightly smaller molar height. Finally, children with Class II-2 had a high lip line and a very large interincisal angle.

Three variables – the sagittal distance between points A and B, the inclination of the symphysis, and the relationship between the maxillary incisal and molar heights - in combination, differentiated nearly 100% correctly between Class II-2 and normal occlusion.

Abstract

This study was designed to gather information on enamel damage concomitant with traumatic debonding of orthodontic brackets. Seventy-eight extracted premolars passed an inspection for defects and were bonded with metal or ceramic brackets. The samples were debonded by one of six methods: (1) conventional clinical debonding, (2) shear force applied slowly and directly onto the bracket, (3) slow shear force applied to an archwire between two brackets, (4 and 5) shear force rapidly applied to the bracket or archwire, or (6) rapid compression (impact) force applied to the face of the bracket. The teeth were microscopically inspected following debonding, and 28% were found to have enamel damage. Within the sample groups, the percentage of damaged samples ranged from 0 to 80%. While the sample sizes were insufficient to generate statistically significant results, there was evidence of the following: (1) Accidental debonding by rapidly applied forces presents a relatively high risk of enamel damage. (2) Ceramic brackets, because of their fragility, may offer some protection by shattering and thus dispersing a rapidly applied force. (3) Direct impact forces may be less dangerous than rapidly applied shearing forces.

Abstract

The craniofacial patterns of 38 sets of parents who had children with cleft lip and/or cleft palate anomalies (experimental group) were compared with the 24 sets of parents of healthy (noncleft) children (control group). Using a computerized program, 248 cephalograms (124 lateral and 124 frontal) were digitized and analyzed. The parents in the experimental group exhibited a distinct craniofacial morphology, including a significant decrease in upper anterior facial height (N-Ans) and total anterior face height (V-Gn). Anterior nasal spine (Ans) and maxillary alveolar process (A) were positioned more anteriorly and superiorly in the experimental group, which contributed to a significant increase in the length of the palate (Ans-Pns) and an anterosuperior rotation of the palatal plane. The cranial base angle in the experimental group was significantly obtuse and the articular angle was smaller than that of the controls. The counterclockwise rotation of the mandible was mitigated by a significant increase in the gonia1 angle. Parents in the experimental group also tended to have faces which were smaller in both transverse and vertical dimensions.

Abstract

This study evaluates 21 children treated with maxillary expansion and protraction appliances for skeletal discrepancies associated with unilateral cleft lip and palate (UCLP). The subjects were treated by the same orthodontist, using the same techniques and appliances. Mean pre- and posttreatment ages were 7.3 and 8.7 years, respectively. Each child was matched by ethnicity, sex, age, and the SN/MP angle to an untreated (non UCLP) control. Stable cranial and cranial base reference structures were used for superimposing serial cephalograms. The results showed definite protraction of the maxilla for the UCLP group. The posterior maxilla of the UCLP group underwent anterior displacement; the posterior maxilla of the control group displayed posterior growth changes. The maxillary incisor tips of the UCLP group demonstrated greater anterior movement than expected for untreated controls. Vertical changes of the maxilla showed no significant group differences. The mandible of the UCLP group was rotated inferiorly and posteriorly; the control group showed inferior/anterior changes. The lower incisor of the UCLP and control groups remained stable and moved anteriorly, respectively. The UCLP group showed significantly greater inferior movements of the anterior mandible than the control group. We conclude that differences between the control and UCLP groups are primarily related to mandibular clockwise rotation and secondarily to anterior maxillary repositioning.

Abstract

The present cross-sectional study was based on orthopantomograms of 1245 Greek children (590 males and 655 females), whose ages ranged from 6 years 10 months to 14 years. Three orthodontic practices were the source of these orthopantomograms which were taken before the start of orthodontic treatment.

The resorption process of the deciduous mandibular canine and molar roots was divided into five stages and the root formation process of their permanent successors into eight stages. The percentage distribution of the deciduous root resorption stages for each root formation stage of the corresponding permanent teeth was then recorded. Exfoliation of these three deciduous teeth occurred when the root formation of their successors had reached the R_2/3, R_3/4, or the beginning of the Rc stage. As far as the effect of local factors on root resorption and formation process our findings indicated that decay, pulp necrosis and pulpotomy hastened the rate of root resorption of the deciduous molars, while they did not influence the rate of root formation of the corresponding permanent teeth.