Abstract

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No Abstracts Available

Abstract

Retromolar dental implants served as anchorage to close first molar extraction sites in five adult patients. Rates of unidirectional space closure for mandibular second molars were assessed with periapical radiographs superimposed on anatomical landmarks and retromolar anchorage implants. Regression analysis revealed that mesial displacement of the midroot area of the leading root was less variable (r=0.97) than for other landmarks on the same teeth: crown (r=0.83), alveolar crest (r=0.82) or apex (r=0.90). When mesial root movement (uprighting) was the principal feature of the initial mechanics (4 of the 5 patients), mesial movement of the apex was about 0.60 mm/mo for the first 8 months and then decreased to about 0.34 mm/mo as the trailing (distal) root of the second molar engaged the relatively dense bone formed by the leading (mesial) root. During the last year of space closure, radiolucent foci were noted l–2 mm ahead of the distal root. These data suggest: (1) sustained orthodontic translation is a physiological manifestation of bone modeling and remodeling throughout the adjacent alveolar process, and (2) rate of mandibular molar translation is inversely related to the apparent radiographic density of the resisting alveolar bone.

Abstract

The present study compared the effect of acetaminophen, ibuprofen and misoprostol on PGE₂ synthesis and orthodontic tooth movement. Guinea pigs were randomly assigned into one of three test groups or a control group. Each group received study treatments every 12 hours as an orthodontic force was applied to the maxillary incisors. Direct linear measurements of tooth separation were recorded at days 2, 4, 6,10, and 11, and inflammatory exudate from the periodontal ligament (PDL) space was extracted and quantitatively analyzed radioimmunologically for the presence of PGE₂ at days 4 and 9. Comparing the concentration of PGE₂ in sample extracts, a significant difference (P=0.001) was found among drug groups. A highly significant difference was found between the mean tooth separation among the various drug groups (P<0.001). At day 11 the misoprostol group exhibited 4.49 ± 0.49 mm of separation; ibuprofen 2.56 ± 0.11 mm, and the control and acetaminophen groups exhibited similar degrees of tooth separation: 3.31 ± 0.07 mm and 3.31 ± 0.08 mm, respectively. A highly significant difference occurred between the mean rates of tooth separation among the various drug groups after day 8 (P<0.001). Results of this study suggest that acetaminophen is the analgesic of choice for the relief of minor discomfort associated with orthodontic treatment.

Abstract

The purpose of this study was to evaluate treatment effects and posttreatment changes following the application of elastic forces from a facemask to the dentition for the early correction of Class III malocclusion. Cephalograms made before and after treatment and at a minimum of 1 year follow-up (mean 3.57 years, SD. 2.07) of 16 patients were compared with those of 13 untreated matched controls. Pretreatment age ranged from 4.58 to 8.25 years (mean 6.80 years, S.D. 1.13), and mean active treatment time was 0.61 years (S.D. 0.15). Available study models at the three time periods were also analyzed. Treatment resulted in a significant improvement in the maxillomandibular relationship and overjet (P < 0.001). The major treatment effect was a downward and backward movement of the mandible and retroclination of the mandibular incisors. However, any skeletal and dentoalveolar advancement of the maxilla contributed to the clinically significant improvement. No differences were observed between the patients and the controls during the posttreatment follow-up. Despite some relapse, the patients demonstrated a net improvement in maxillomandibular relationship and overjet at the end of follow-up relative to the controls. Overcorrection of the overjet during treatment may be important for maintaining a successful correction.

Abstract

Cleft lip and palate patients often develop maxillary retrusion after cleft repair. Maxillary protraction treatment during early childhood helps to achieve more favorable occlusion with positive overjet and overbite and allows a more normal growth pattern to occur. The purpose of this study was to investigate the skeletal and dental changes during reverse headgear treatment in a homogenous group, i.e., Chinese boys born with unilateral complete cleft lip and palate.

The results showed that after 7.8 months of reverse headgear wear, normalization of the sagittal maxillomandibular relationship (ANB angle) was achieved. Significant skeletal changes included anterior position of the maxilla and posterior position of the mandible. Dental changes within the respective skeletal units were not significant except for the mandibular molar.

Abstract

The purpose of this study was to determine the incidence of ectopic eruption of the maxillary first permanent molars in cleft patients. Panoramic radiographs of 70 Brazilian Caucasian children, 6 to 8 years old and with complete unilateral cleft lip and alveolus, were assessed. Fourteen of 70 patients (20%) presented with ectopic eruption of one or both maxillary first permanent molars. Sixteen of 19 ectopically erupted molars (85%) were of a reversible type of ectopic eruption and 3 (15%) were irreversible. No significant differences were found between sexes or between cleft sides.

Abstract

The study examined the reliability among seven orthodontists in judging dental and facial aspects of malocclusion in a screening of elementary schoolchildren. Data included measures typically recorded during a clinical orthodontic examination: facial assessment of skeletal/incisor relationships and individual measures of morphologic malocclusion. Interexaminer reliability data were collected on 52 children. Pairwise comparisons between orthodontists were made using exact percent agreement and agreement within one category. Kappa statistics and one-sided Z-tests were used to evaluate observed agreement compared with agreement that would be expected by chance. Median Kappa statistics indicated that the reliability of maxillary and mandibular anteroposterior positions, incisor exposure, interlabial gap, and maxillary crowding was poor (K<0.40). Acceptable reliability existed for mandibular anterior crowding, facial convexity, overbite, overjet, and molar classification (median Kappas ranged from 0.48 to 0.72). Excellent reliability existed only for evaluating the presence of a posterior crossbite (K=0.79). The results caution that the language of clinical orthodontic diagnosis is imprecise.

Abstract

The purpose of this study was to describe the pattern of bony and soft tissue growth of the oropharynx in a sample of healthy, orthodontically untreated children. The sample consisted of 16 males and 16 females with lateral cephalograms at 6, 9, 12, 15, and 18 years of age, for a total of 160 lateral cephalometric radiographs. All subjects were enrolled in the Broadbent Bolton Study¹ and their radiographs were used to produce the Bolton Standard Templates.² Each radiograph was traced by hand and the tracings were paired and averaged to create a standard template for pharyngeal tissues at each age. In addition, all 160 tracings were digitized and means and standard deviations were calculated for 29 hard and 7 soft tissue measurements. Four linear (Ar-H,S-H,Go-H, Gn-H) and three angular (N-S-H, SN-ArH,GoGn-H) measurements demonstrated that the hyoid bone descends and moves slightly anteriorly up to age 18. The soft palate (PNS-P) increased 1 mm in length and 0.5 mm in thickness every 3 years after age 9. The distance between the anterior border of the atlas (ATA) and PNS did not change after age 12, while two soft tissue.measurements (PNS-pharyngeal wall [PhW2] and posterior soft palate to pharyngeal wall [psp-PhWS]) increased. In general, two periods of accelerated change (6–9 years and 12–15 years) and two periods of quiescence (9–12 years and 15–18 years) were identified for the pharyngeal soft tissues. Further studies are needed to determine if soft tissues in the oropharynx continue to change after age 18.