Abstract: Interincisor angulation is commonly held to be a critical factor in determining overbite depth, where there is incisor contact. In this study significant correlations between these variables were found in Class II, division 2 malocclusions although interincisor angle explained less than a third of the variance in overbite depth. It was found that the anteroposterior relationship of the lower incisor edge to the upper incisor root centroid is more strongly related to overbite depth and it is suggested that this is a useful factor to take into account in planning treatment in Class II cases.

Abstract: The purpose of this study was to compare the effect of overjet and overbite correction in non-extraction and extraction therapy in a sample of Class II malocclusions treated with the Edgewise appliance. The subjects were 20 children treated without extraction and 20 children treated with extraction of the four first premolars. During the post-treatment period a relapse of overjet and overbite occurred in both groups. However, there was a beneficial net effect of overjet and overbite correction in both groups with no significant difference between the two groups. The study showed that mandibular intercanine width, space conditions in the lower jaw and mandibular incisor position were important factors in treatment planning.

Abstract: The authors studied the frequency of overjet, overbite and open bite in deciduous dentition in one hundred and twenty Brasilian white children, of both sexes, aged between 2 and 6 years old. The results showed that the deciduous dentition of that children was characterized for a moderate overjet and a light overbite and that overjet and open bite degree decrease with the increasing of the children's age.

Abstract: Size of central incisors is a significant factor in selection of anterior teeth for all types of dentures. The purpose of this study was to evaluate the relationship between the width of maxillary central incisors and philtrum. The average width of the central incisors and philtrum observed in male subjects were 8.510 mm. (right), 8.516 mm. (left) and 14.105 mm. Those in female subjects were 8.280 mm. (right), 8.293 mm. (left) and 12.271 mm. There was a significant difference (p less than 0.05) in size between the width of each central incisor and philtrum for either male or female subjects. However, there was a direct correlation between the width of the central incisors and philtrum in these 200 subjects (p less than 0.05).

Abstract: The orthodontic profession has assumed much of the responsibility for the improvement in function of the teeth and jaws. Since function is closely associated with overbite, the correction of vertical overbite discrepancies comprises a major part of clinical orthodontics. This investigation was undertaken to describe the movements that teeth undergo during the correction of excessive overbites and to correlate these movements to the change in overbite. A total of 87 cases were selected from the records of the Indiana University School of Dentistry, Department of Orthodontics. The selected cases had an excessive pre-treatment overbite of 4.0 mm or more as seen cephalometrically and a satisfactory post-treatment result. In addition, they were clinically determined to be post-pubertal, indicating essentially no growth potential during the treatment period. Pre and post-treatment tracings of the cephalograms were made and measurements collected from the tracings. Superimpositions were prepared of the pre and post-treatment radiographs and the general trends that appeared were noted. The change in overbite was correlated to tooth movements of the Class II Division 1 correction using the Pearson test of correlation coefficients. The results indicate that the tooth movements most commonly seen in treatment to reduce excessive overbite occur mainly in the mandibular arch. In Class II Division 1 cases, the change was significantly correlated to the reduction in vertical height of the mandibular incisor and to the increase in the angulation of the mandibular incisor to the mandibular plane. Not all measurements recorded were significantly correlated to the change in overbite.(ABSTRACT TRUNCATED AT 250 WORDS)

Abstract: This paper reports on a rare case of horizontal impaction of the mandibular left and right deciduous central incisors. The patient was a 4 year and 7-month-old-girl at the time of first visit to our clinic. She had no previous history, and there was no family history or anomaly in her general physical condition. All the deciduous teeth except the mandibular left and right deciduous central incisors had already erupted. The right deciduous central incisor was impacted completely and the left one erupted with its incisal edge about 2 mm at the lingual gingiva. In the X-ray examination, the horizontal impaction of the mandibular left and right deciduous incisors were noted. There were no cysts, odontoma or tumors. Both of them were extracted to prevent loss of space for the permanent central incisors. Each root of both teeth was curved 90 degrees in the lingual direction at half of length of the root. There was no anomaly of figure and color in their crowns. In the histopathologic examination, there was no anomaly except for the small root resorption at the labial and lingual sides. 3 years and 3 months after extraction of the deciduous central incisors, approximately two thirds of the crowns of the left and right mandibular permanent central incisors have erupted. Both of them incline to the lingual direction and rotate and there is a space of about 5 mm between them. This case is still under observation.

Abstract: Overbite values in 650 Nigerian children aged 11-13 years have been measured using the Jackson method of overbite classification. The commonest overbite value in Nigerian children is 1 with a prevalence of 75.3 per cent which is followed by overbite 2 with a prevalence of 16.3 per cent. The study showed that Nigerians have a lesser overbite value compared with Caucasians.

Abstract: Roentgencephalometry was used during the investigation of the effects of some therapeutic factors on the growth and development of the jaws in 64 adult males with an isolated cleft palate repaired by pushback. The anterior growth of the maxilla was not related to the age at the time of surgery or to orthodontic therapy with removable appliances. A small number of individuals operated during adolescence had also a shorter depth of the maxilla similarly as patients operated upon during early childhood. Anterior crossbite developed mostly in patients with reduced proclination of the upper alveolar process, while, on the contrary, a retrusion of the maxilla played no essential part. This observation proves useful for the prediction of the development of this malocclusion. The angle of sagittal jaw relations does not represent necessarily a valid criterion of the development of the jaws. In the presence of an overbite retrusion of the maxilla is associated with a retroposition of the mandible and thus the angle of sagittal jaw relations remains unchanged. Thus overbite represents an effective mechanism acting on the position of the mandible. A differentiated approach for the determination of the age of choice at the time of palate surgery according to the type and extent of the cleft is proposed.

Abstract: It is known that some of the deciduous reversed bite cases are corrected spontaneously by themselves. No decisive conclusion, however, has been achieved so far as to what morphological characteristics the self corrected cases have. The purpose of this study, therefore, was to determine whether the difference between the self corrected group (n) and the non-self corrected group (r) exists at their initial examination or if it occurs as a result of changes in occlusion. The materials used in this study were the serial plaster casts of 29 Japanese girls with the deciduous reversed bite at their first visit and these were measured with the three dimensional measurement system. The following results were obtained: 1. Characteristics of the initial examination with the n group: Overjet (-) and overbite in the n group were smaller than in the r group. The arch length and the perimeter of the maxillary dentition in the n group were longer, and the area of the incisive bone (U-C) was wider than in the r group. Moreover, the upper and lower canines in almost all of the n group cases were not touching each other and did not restrict mandibular movement, resulting in easy attrition for the deciduous anterior dentition. 2. Longitudinal changes in the n group: Mean change of this group showed a decrease in overbite caused by the attrition of the deciduous central incisors and the continuous eruption of the maxillary second deciduous molars. Overjet also decreased, because of an increase in the maxillary anterior arch length and of backward movement in the mandibular dental arch. Individual changes were much alike in mean changes in almost all of the measured items. Arch width between canines in the maxilla and arch length in the mandible decreased in some cases, suggesting that a discrepancy would occur when the permanent incisors erupt. 3. Longitudinal changes of the r group: Mean changes showed that overbite decreased in the same pattern as the n group, but overjet did not change and the mandible did not show backward movement. The reason was that overbite in this group was deeper than in the n group at the initial examination. Moreover, deciduous molar to molar width became wider to compensate the decrease in the arch length and the perimeter. Individual changes showed that some of the r group cases had a tendency to improve, but some became worse.

Abstract: The purpose of the present study was to investigate the developmental changes of dental arch forms by using longitudinal materials. The data was derived from dental casts and roentgenographic cephalograms collected from a longitudinal growth study of Japanese children from the age of 5 to 15 years. The materials were divided into three groups of occlusion at the time that the children had full permanent dentitions as follows; normal occlusion group (N-group; N = 19), Angle's class I crowding group (CR-group; N = 11), Angle's class II malocclusion group (CL2-group; N = 7). In addition, members of these groups were classified into three developmental stages as follows; deciduous, mixed and permanent dentition. The developmental changes in dental arch forms were analyzed from metrical measurements of dental casts and roentgenographic cephalograms. The measurements, such as dental arch lengths, widths, amount of interdental space or crowding, mesiodistal crown diameters, overjet and overbite, were obtained from dental casts, and those of incisor inclination angles and ANB angles were from roentgenographic cephalograms. Finally, principal component analysis was performed to clarify the developmental changes of dental arch forms in the series of longitudinal data. The results were as follows; 1. A method was devised for drawing dental arch forms directly from dental casts using compasses, sliding calipers and rulers. 2. Dental arch lengths and widths of the CR-group were uniformly smaller from the deciduous to permanent stages than those of the N-group. 3. The CL2-group showed nearly the same sizes of arch lengths and widths as the N-group at the deciduous stage. Nevertheless, these dimensions of the CL2-group increased considerably and showed larger sizes of arch lengths and widths than the N-group in mixed and permanent stages except in the case of maxillary arch widths. 4. The sum of mesiodistal crown diameters of the CR-group were quite similar to those of the N-group in all three stages. On the other hand, the CL2-group tended to be larger in both arches than the N-group in all stages. 5. So far as the deciduous stage is concerned, the amount of interdental space was significantly larger in the N-group than in the other two groups. 6. Throughout all stages, there were no significant differences in the maxillary central incisor inclination angles among the three groups, while the CR-group tended to show lingual inclination of the mandibular central incisor compared with the other two groups.(ABSTRACT TRUNCATED AT 400 WORDS)

Abstract: Dummy- and finger-sucking habits were investigated among 60 5 year olds, born in 1982. The children were living in Raufoss, a small rural community in eastern part of Norway. Information about the sucking habits was obtained from their parents by means of questionnaires. The position of the teeth and the occlusion were registered by an orthodontist. Total prevalence of sucking habits was 63%. Thirty-seven percent, had used a dummy and 30% had been or were still finger-suckers. Two children had both used a dummy and sucked their fingers. This is a significant lower total prevalence of sucking habits than recorded in recent Swedish and Danish studies (1-8), but comparable with a Swedish study from 1971 (9). Most dummy-suckers had broken their habits at 3-4 years of age, while the finger-suckers were still active at 5 years of age. Finger-sucking had the largest impact on the position of the front teeth. The finger-suckers had significantly larger overjet and smaller overbite, more proclined upper incisors and retroclined lower incisors than dummy-suckers and those without any sucking habit. The only measurable effect of previous dummy-sucking of 5 years of age was a more open position of the lips and a smaller overbite. Otherwise, no significant effect on the occlusion was observed in any of the dummy- or fingersuckers.

Abstract: The results of an epidemiological investigation on the prevalence of malocclusions in the school population of the Province of Trieste carried out on a sample of 2099 subjects aged 10 and 12 are reported. Subjects were classified according to Angle classes. Other malocclusion parameters such as overjet, overbite, median line deviation, crossbite and upper and/or lower crowding have also been investigated.

Abstract: The purpose of the study was to evaluate the result in adults of Class I malocclusion cases who had all their first premolars extracted as the sole treatment of space deficiency in the mixed or early permanent dentition. The mean age at premolar removal was 10½ years. Forty-two out of 44 cases were re-examined at a mean age of 30 years and 4 months. Observations of dental occlusion and oral health were compared to observations of control samples. The average malocclusion in the adults, as judged by a score method, was similar to that reported for an appliance-treated sample. Marked spontaneous arch alignment and residual space closure with age was seen in most cases. Despite earlier tooth removal, on average crowding developed to about the same degree as that of an non-extraction normal occlusion sample. No detrimental effects were seen with regard to overjet or overbite. Neither did the figures for lower incisor position at the follow-up examination differ from that of the normal occlusion sample. Although tipping of adjacent teeth towards the extraction site was frequent, especially in the mandible, no effect on marginal bone height was evident as judged by comparison with a nonextraction control sample. The results reveal a significant capacity for spontaneous improvements with age in dental arch morphology and relationship in extraction cases, provided that specific features have been looked for in case selection.

Abstract: The aim of the present study was to evaluate whether or not there are any differences in the dentition between children with enlarged tonsils and those with normal tonsils. A sample of 73 children (33 boys and 40 girls) with enlarged tonsils and with a mean age of 10.1 years was compared with a normal control group, matched for age and sex. Eighteen dentition variables and thirty-two variables in anamnestic, clinical, pharyngeal and postural findings were recorded. Measurements were obtained from lateral skull radiographs and dental casts. Group means were compared. Relationships between variables were studied using simple correlations and multiple stepwise regression analyses. It was found that children with enlarged tonsils had more retroclined lower incisors, more anteriorly positioned upper incisors, smaller overbite, larger overjet, shorter lower dental arches, narrower upper dental arches and an increased frequency of lateral crossbite. Functional and/or morphological disorders, causing an open posture of the mouth, a lowered anterior posture of the tongue and a low position of the hyoid bone are thought to be associated with the differences in the dentition between the two groups. Obstruction of the oropharynx by enlarged tonsils, might be one factor responsible for these dysfunctions.