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Dentofacial features of children with distal occlusions, large overjets, and deepbites in the early mixed dentition.

INTRODUCTION: The aim of this investigation was to analyze craniofacial morphology in children with distal bites, large overjets, and deepbites in the early mixed dentition. METHODS: The sample comprised 486 Finnish children who are participating in an ongoing clinical trial. Cephalograms were obtained at the deciduous-mixed dentition interphase for the baseline of the trial. The mean age of the children was 5.1 years (SD, 2.6; range, 4.0-7.8 years). RESULTS: Subjects with bilateral distal steps of > or =1 mm compared with normal had long midfaces (P <.05), short and retrusive mandibles (P <.05), small maxillomandibular differentials (P <.001), convex profiles (P <.01), retrusive mandibular incisors (P <.01), and large interincisal angles (P <.001). Children with overjets of > or =4 mm had retrusive mandibles (P <.001), long maxillae and midfaces (P <.001), small maxillomandibular differentials (P <.001), convex profiles (P <.001), and protrusive maxillary and retrusive mandibular incisors (P <.001). Children with deepbites (overbites of > or =4 mm) had short and retrusive mandibles (P <.05), long midfaces (P <.001) and maxillae (P <.05), small maxillomandibular differentials (P <.001), convex profiles (P <.01), retrusive mandibular incisors (P <.001), and large interincisal angles (P <.001). No differences were found in the length of anterior cranial base, the position of maxilla relative to cranial base, lower facial height, and facial axis angle between any malocclusion group and normal children. All correlations between the occlusal and skeletal characteristics were low, suggesting only weak associations at this stage of development. CONCLUSIONS: These results indicate that the early dentofacial features of children with distal occlusions, large overjets, and deepbites differ from normal values. However, the skeletal patterns of these 3 malocclusion types showed considerable similarities, with long but neutrally positioned maxillae, retrusive mandibles, small maxillomandibular differences, convex profiles, retrusive mandibular incisors, and large interincisal angles, but normal growth directions and lower facial heights as common features.

Analysis of Variance↗

Treatment effects of the edgewise Herbst appliance: a cephalometric and tomographic investigation.

INTRODUCTION: The crown Herbst appliance was introduced in the late 1980s because of shortcomings of the banded Herbst. In edgewise Herbst treatment, a fixed appliance is used with the crown Herbst to maximize the skeletal effects of treatment. Treatment response to the edgewise Herbst appliance has not been reported in the literature. Our objective was to investigate skeletal and dental changes in patients with Class II malocclusions treated with the edgewise Herbst appliance. METHODS: Fifty-two consecutive patients were treated with the edgewise Herbst appliance; 32 (18 girls, 14 boys) met the criterion of 16 months out of Herbst treatment and were included in the study. Mean treatment time with this appliance was 8.0 +/- 1.8 months. Patients in the mixed dentition received additional treatment with 2 x 4 appliances until proper overbite, overjet, and torque on the incisors and permanent first molars were achieved. Patients in the permanent dentition were treated with full appliances to finalize the occlusion. Cephalometric measurements were taken at pretreatment, posttreatment, and 16 months after removal of the Herbst appliance, and the results were compared with 32 untreated Class II subjects from the Bolton Brush Study, matched for sex, age, and cephalometric dentofacial morphology. Data were analyzed with ANOVA, Tukey-Kramer multiple comparison tests, and 2-tailed t tests. RESULTS: After 8 months of Herbst treatment, incisal relationship was overcorrected to an end-to-end incisal relationship and improved 8.4 mm, compared with the control group. The maxilla moved backward 1.4 mm at Point A, and the mandible moved forward 1.7 mm. The maxillary incisors moved lingually 1.7 mm, and the mandibular incisors were proclined 3.6 mm. The molars were corrected to a Class III relationship with a change of 7.2 mm compared with the control group. The mandible moved downward and forward. However, the condyle showed only 0.2 mm forward movement in the fossa. Sixteen months after appliance removal, the molars had relapsed into a Class I relationship, for a net change of 2.4 mm compared with the control group. Net overjet gain was 2.7 mm. Net restraint of maxillary growth was 1.3 mm, and net forward movement of the mandible was 1.0 mm. The maxillary incisors had no net movement, and the mandibular incisors had a net forward movement of 0.3 mm. Overall, skeletal change contributed 85% of the net overjet correction. CONCLUSIONS: Class II treatment with the edgewise Herbst appliance is accompanied by both skeletal and dental changes. The changes are stable, with significant skeletal differences remaining 16 months after appliance removal. The forward and downward movement of the mandible with minimal changes in the position of the condyles in the fossae suggests a combination of condylar growth and remodeling of the glenoid fossa with treatment.

Analysis of Variance↗

Cephalometric norms of Nigerian children.

INTRODUCTION: The purpose of this study was to develop cephalometric standards for Nigerian children. METHODS: The average values of 7 dentoskeletal angles were determined from standardized lateral head radiographs of 100 schoolchildren (aged 11 to 13 years; mean, 12.6 years) in Enugu, a city in southeastern Nigeria. The children, born to Nigerian parents of Igbo ancestry (Igbo is 1 of the 3 major ethnic groups in Nigeria), were selected on the basis of a well-balanced face and acceptable profile, Class I occlusion with normal overjet and overbite, minor or no crowding or spacing, and no history of orthodontic treatment. RESULTS: There were no statistically significant differences in cephalometric measurements between boys and girls; thus, the data were combined for analysis. The mean values and standard deviations obtained for the measured variables were: SNA, 85.5 degrees (+/- 4.3 degrees); SNB, 81.2 degrees (+/- 4.0 degrees); ANB, 4.3 degrees (+/- 2.5 degrees); UI-FP, 122.8 degrees (+/- 7.5 degrees); Ll-MP, 98.8 degrees (+/- 5.8 degrees); Ul-LI, 109.1 degrees (+/- 8.0 degrees); and FMA, 26.1 degrees (+/- 5.0 degrees). CONCLUSIONS: Compared with the norms for other ethnic groups, Igbo children have a prognathic relationship of the maxilla and the mandible to the anterior cranial base with a tendency toward a protrusive skeletal pattern. The children also exhibited prominent bimaxillary proclination with procumbent and protrusive maxillary and mandibular incisors and a steep Frankfort-mandibular plane angle. The findings emphasize the need for group-specific norms for orthodontic diagnosis and treatment planning, and provide cephalometric standards for Igbo children.

Adolescent↗

Relapse of anterior crowding in patients treated with extraction and nonextraction of premolars.

INTRODUCTION: The purpose of this study was to evaluate long-term stability of incisor crowding in orthodontic patients treated with and without premolar extractions. METHODS: Dental casts and cephalometric records of 98 patients were evaluated before treatment (T1), at posttreatment (T2), and at postretention (T3). Half of the patients had been treated with extractions, and half were treated nonextraction. RESULTS: Irregularity, as measured by the irregularity index, decreased 5.51 mm in the extraction group and 2.38 mm in the nonextraction group. Mandibular incisor irregularity increased 0.97 mm in the extraction group and 0.99 mm in the nonextraction group, respectively, in the postretention period. Maxillary incisor irregularity relapse was smaller than mandibular incisor relapse for both groups. Intercanine width expanded during treatment. At T3, mandibular intercanine width decreased in both groups, but the differences were not statistically significant. At T3, intermolar width was stable, arch depth decreased, overbite and overjet slightly increased, SN mandibular plane angle decreased, and incisor positions in both groups tended to return to T1 values. Clinically acceptable stability was obtained. CONCLUSIONS: With the exception of the interincisal angle, no statistically significant differences were recorded between the extraction and nonextraction groups from T2 to T3. No statistically significant correlations were found between any variables studied and mandibular incisor irregularity at T1, T2, and T3.

Adolescent↗

Occlusal and cephalometric Class II Division 1 malocclusion severity in patients treated with and without extraction of 2 maxillary premolars.

INTRODUCTION: The purpose of this study was to compare the initial occlusal and cephalometric severity of Class II Division 1 malocclusion patients treated with and without extraction of 2 maxillary premolars. METHODS: Dental study models and cephalograms of 62 patients were selected. Those in group 1 (n = 42) were treated without extractions, and those in group 2 (n = 20) were treated with 2 maxillary premolar extractions. Grainger's treatment priority index (TPI) was used to assess the final and the initial occlusal status of each subject. Variables such as overjet and overbite were also evaluated. Independent t tests were used to compare the occlusal variables at the posttreatment stage, the occlusal and cephalometric variables at the pretreatment stage, and the improvement in TPI values between the groups. RESULTS: Patients treated with 2 maxillary premolar extractions had greater initial occlusal TPI values, overjets, cephalometric apical base anteroposterior discrepancies, maxillary incisor protrusions, and anteroposterior molar discrepancies than those treated without extractions. CONCLUSIONS: For patients with more severe anteroposterior discrepancies, an extraction plan provides more effective treatment with less need for patient compliance.

Adolescent↗

Outcome of treatment of Class II malocclusion by intraoral mandibular distraction.

Our aim was to find out long-term results of treatment in patients treated orthodontically and by mandibular distraction osteogenesis. Data on duration of treatment, costs, and results of 26 patients (13 girls and 13 boys) with a mean age of 15 years were analysed. The preoperative cephalograms were compared with those taken at the last follow-up visit. There was a significant reduction in duration of treatment when patients were treated without a first phase that included functional appliances. The differences in costs of orthodontic treatment were not significant. The costs of the operation for distraction were significantly higher compared to BSSO, mainly because of the costs of the distraction devices. Comparison of the cephalograms showed a significant increase in SNB angle, Wits value, ANB angle, overjet, and overbite. The Y-axis, MP/S, and SpP/MP angle increased. Orthodontic treatment and distraction of the mandible was a successful, but more expensive, treatment.

Adolescent↗

Non-surgical risk factors for condylar resorption after orthognathic surgery.

BACKGROUND: Condylar resorption following orthognathic surgery is an important cause of late skeletal relapse. However, its pathogenesis is not well understood. The purpose of this study was to find non-surgical risk factors for condylar resorption after orthognathic surgery. PATIENTS: In this retrospective study, 17 patients (Group I) who developed postoperative condylar resorption were selected. These patients were compared with 22 patients (Group II) without postoperative condylar resorption, but who showed mandibular hypoplasia with a preoperative high mandibular plane angle of more than 40 degrees. METHODS: Possible non-surgical risk factors were sought by analysing clinical and radiological data collected preoperatively and immediately, 6 weeks, and 1 and 2 years postoperatively. RESULTS: There was no significant difference of gender distribution between the two groups. Patients in Group I were significantly younger (p=0.02) than those in Group II. The incidence of temporomandibular joint dysfunction in both groups was similar preoperatively, but was significantly higher (p=0.001) postoperatively in Group I. The posterior inclination of the condylar neck in Group I was also significantly greater (p<0.001). The preoperative mandibular plane angle in Group I (mean value: 49.4 degrees ) was significantly greater (p=0.005) than in Group II (mean value: 44.9 degrees ). The preoperative SNB angle, overbite, and posterior facial height and ratio (posterior/anterior facial heights) in Group I were significantly smaller (p<0.05). CONCLUSION: The present study suggests that the posteriorly inclined condylar neck should be considered as a relevant non-surgical risk factor.

Adolescent↗

A similarity function to evaluate the orthodontic condition in patients with cleft lip and palate.

The objective of this work is the modeling of a similarity function adapted to the medical environment using the logical-combinatorial approach of pattern recognition theory, and its application to compare the orthodontic conditions of patients with cleft-primary palate and/or cleft-secondary palate congenital malformations. The variables in domains with no a priori algebraic or topological structure are objects whose similarity or difference is evaluated by comparison criteria functions. The range of these functions is an ordered set normalized into the unit interval, and they are designed to allow differentiation and non-uniform treatment of the object-variables. The analogy between objects is formalized as a similarity function that stresses the relations among the comparison criteria and evaluates the partial descriptions (partial similarity/difference) or total descriptions (total similarity/difference) of the objects. For the orthodontic problem we defined a set of 12 variables featuring the unilateral/bilateral fissures, the conditions of maxilla, premaxilla, mandible and patient's bite. The comparison criteria (logical for malocclusion, fuzzy for maxillary collapse unilateral/anteroposterior and for overbite, and Boolean for protrusive/retrusive premaxilla conditions) were assigned a relevance factor based on the orthodontist accumulated knowledge and experience. The modeling of the similarity function and its effectiveness in comparing orthodontic conditions in patients are illustrated by the study of four clinical cases with different clefts. The results through similarity are close to the expected ones. Moreover evaluated at different moments it allows to assess the effect of treatment in a single patient, hence providing valuable auxiliary criteria for medical decision making as to the patient's rehabilitation. We include the potential extension of the methodology to other medical disciplines such as speech therapy and reconstructive surgery.

Algorithms↗

Long-term maxillomandibular skeletal and dental changes in children with cleft lip and palate after maxillary distraction.

Long-term skeletal and dental changes were examined in 8 children with cleft lip and palate who underwent maxillary distraction to allow the maxilla to catch up to their mandibular growth at the treatment point. Changes in the overjet (OJ), overbite (OB), and positions of the anterior nasal spine (ANS), upper incisors (U1), pogonion (Pog), and lower incisors (L1) were measured on preoperative to 36 months postoperative lateral-cephalograms. In most of the children, the long-term changes after the maxillary distraction resulted in an inferior growth of the maxilla and anteroinferior growth of the mandible. This seems to suggest that maxillary distraction performed during childhood needs considerable overcorrection. However, if the maxilla is distracted to an adult position during childhood, the masticatory functions of the children will markedly deteriorate until their jaws grow. Therefore, we believe that one goal of maxillary distraction during childhood can be to allow the maxilla to catch up to the mandibular growth of the children at the treatment point.

Adolescent↗

A sibship with unusual anomalies of the eye and skeleton (Michels' syndrome).

Four siblings of nonconsanguineous parents had congenital anomalies of the anterior segment of the eyes, eyelids, and skeletal systems. Anomalies of the anterior segment included opacities of the corneal stroma, conjunctival telangiectasia, and iridocorneal adhesions. Eyelid abnormalities included blepharoptosis, blepharophimosis, and telecanthus. One sibling with extensive anterior segment anomalies developed glaucoma. All subjects had impaired vertical gaze. Oromandibular anomalies varied from cleft lip and palate to malocclusion with overbite. Additional features included subnormal intelligence, short stature, hearing loss, and clinodactyly. This spectrum of anomalies appeared to have been transmitted as an autosomal recessive syndrome.

Abnormalities, Multiple↗

Maturation of untreated normal occlusions.

The dental casts of 65 untreated normal occlusions were evaluated to determine the nature and extent of the developmental maturation process of the normal dentition. Six dental parameters were examined in the mixed dentition (9 to 10 years), early permanent dentition (12 to 13 years), and early adulthood (19 to 20 years). Results showed decreases in arch length and intercanine width; minimal overall changes in intermolar width, overjet, and overbite; and increases in incisor irregularity. Females showed more severe changes than males. The individual changes found were not correlated to changes in any of the other parameters measured. No associations or predictors of clinical value were found. The changes found in a sample of untreated normals were similar in nature but lesser in extent than postretention changes found in a sample of treated cases.

Adolescent↗

Implications of the failure rates of bonded brackets and eyelets: a clinical study.

A clinical study of the rate of failure of bonded brackets and eyelets on primary molars was undertaken. Two groups of patients (one bonded contralaterally and the other at random) were studied for 12 to 17 months. The data support the hypothesis that one major cause of bond failure is the force of occlusion during mastication. On the basis of this finding, several clinical applications are suggested. These include rotation of second premolars, closure of extraction spaces, and the management of limited treatment of lower incisors in the presence of deep, traumatic overbite.

Bite Force↗

Quantification and validation of predictive values of occlusal variables in temporomandibular disorders using a multifactorial analysis.

STATEMENT OF PROBLEM: A consensus is lacking on the association between occlusal variables and temporomandibular disorders (TMDs). PURPOSE: This study estimated the maximum potential power of occlusal variables to differentiate patients with TMD from asymptomatic normal adult subjects. MATERIAL AND METHODS: The occlusal characteristics in 2 sets of female patients with intracapsular TMD (1993, n = 257, and 1998, n = 124) differentiated into disk displacement and osteoarthrosis subdiagnoses were compared with asymptomatic female controls (n = 51 and 47) with multiple logistic regression analysis. Significant variables and total contribution to the log likelihood were compared with the predictive value of univariate analysis, including sensitivity and specificity. RESULTS: Occlusal factors in the females (1993, 1998) explained no more than 4.8% to 27.1% of the log likelihood. In comparison to the logistic regression analysis, univariate analysis was less predictive of patients with TMD, due to notably lower sensitivity. Patients with disk displacement were mainly characterized by unilateral posterior crossbite and longer RCP-ICP slides. Patients with osteoarthrosis were most consistently characterized by longer RCP-ICP slides and larger overjet, and in part to reduced overbite. Significant relative risk for disease (odds ratio > 2:1) was mainly associated with infrequent, more extreme ranges of occlusion measurements. CONCLUSION: Occlusal factors may be cofactors in the identification of patients with TMD, but their role should not be overstated. Some occlusal variation may be a consequence of rather than a cause for TMD. Single variables have more limited value and it takes sets of adverse variables to model TMD. Combinations of variables appear to be disease specific. Some extreme ranges of occlusion were the domain of patients with TMD, but most patients were within the normal ranges.

Adult↗

Intraoral distraction osteogenesis in the baboon mandible using a tooth and bone-anchored appliance.

PURPOSE: The purpose of this study was to determine the feasibility of using an intraoral, bone and tooth-anchored appliance to distract baboon mandibles using the principles of distraction osteogenesis (DO). MATERIALS AND METHODS: Seven juvenile baboons were used in this study. Mandibular corticotomies were made in the ramus of the mandible unilaterally (n = 5) or bilaterally (n = 2), and a "pin-in-tube" (PIT) distraction appliance was applied. The device was secured to the mandibular ramus posterior to the cortical cut with a bicortical screw and anteriorly to an occlusal splint. The appliance was activated an average of 0.86 mm/d (0.5 to 1.3 mm/d) for an average of 12.4 days (10 to 14 days). Predistraction and postdistraction measurements were made between metallic markers placed in the distraction area, in the dental midline, and of the overjet and overbite. RESULTS: Bone healing was complete in all mandibles. The average mandibular lengthening measured between the metallic markers was 7.9 mm. The mandibular midlines showed an average of 4.25 mm of lateral movement in the unilaterally distracted mandibles. There were no infections. CONCLUSIONS: The results of this study indicate that an intraoral bone and tooth-anchored distraction appliance is an effective method to produce lengthening in the mandible by distraction osteogenesis.

Animals↗

Modification of the maxillary Le Fort I osteotomy in cleft-orthognathic surgery: the bilateral cleft lip and palate deformity.

The adolescent with bilateral cleft lip and palate (BCLP) undergoing orthognathic surgery may have multiple residual clefting problems, including a mobile, dysplastic premaxilla and hypoplastic lateral maxillary segments, with each segment misaligned in three dimensions. These problems are commonly compounded by residual oronasal fistulas, bony defects, soft-tissue scarring from previous surgery, and the congenital absence of the maxillary lateral incisor teeth with resulting cleft-dental gaps. This article describes modifications of the Le Fort I osteotomy that allow for the simultaneous routine and safe management of these deformities. Results of this operation on 22 consecutive patients are reported, with findings of follow-up ranging from 1 to 5 years. The long-term parameters reviewed include closure of residual oronasal fistulas, stabilization of the premaxilla, cleft-dental gap closure, maintenance of attached gingiva at the cleft site, maintenance of a positive overjet and overbite, the need for prosthetics to complete dental rehabilitation, and surgical morbidity.

Adolescent↗

Stability after surgical correction of mandibular prognathism using the sagittal split ramus osteotomy and fixation with poly-L-lactic acid (PLLA) screws.

PURPOSE: This study was designed to examine skeletal stability after surgical correction of mandibular prognathism using a sagittal split ramus osteotomy (SSRO) and fixation with poly-L-lactic acid (PLLA) screws. PATIENTS AND METHODS: Twenty patients with Class III malocclusion were treated with bilateral SSRO and mandibular setback. Ten underwent fixation with titanium screws (group I) and the other 10 with PLLA screws (group II). Cephalograms were obtained 2 or 3 days postoperatively, and at 3, 6, and 12 months after the operation. Changes in the position of upper incisors (U-1), lower incisors (L-1), B-point, and pogonion were examined on lateral cephalograms. RESULTS: Certain tendencies for overjet and overbite were noted to have decreased more markedly, and changes in the position of the skeletal points were greater in group II than in group I. However, statistical analysis showed no significant differences between the two groups. CONCLUSION: Our results suggest that fixation of the bony segments with PLLA screws after SSRO may be used effectively in properly selected cases.

Adolescent↗

Eruption Guidance Appliance effects in the treatment of Class II, Division 1 malocclusions.

The objective of this research was to cephalometrically evaluate the possible effects of the Eruption Guidance Appliance on the craniofacial complex in a sample of 30 patients, over a treatment period of 26 months. The experimental sample consisted of 30 patients (13 females and 17 males), 27 of which presented with a Class II, Division 1 malocclusion and 3 with a Class I malocclusion. The mean initial chronologic age was 9 years; the treatment period lasted 26 months. A control group was used for comparison and consisted of 30 subjects (13 females and 17 males) of similar ages and spanned a similar observation period. Twenty-six subjects of this control group had Class II, Division 1 malocclusions, and 4 had Class I malocclusions. Lateral cephalometric headplates were obtained for the experimental group initially and after 26 months of treatment. The subjects in the control group were randomly selected from a serial growth study sample from the Orthodontic Department at Bauru Dental School, University of São Paulo, for whom cephalometric headplates were obtained annually from 4 to 18 years of age. Comparative statistics were used to assess possible differences between the experimental and control groups during the 26-month period of observation. Results demonstrated statistically significant increases in mandibular growth, degree of mandibular protrusion, lower anterior and total anterior face height, mesial migration of the lower molars, and mandibular posterior dentoalveolar height. There was also lingual tipping and retrusion of the upper incisors, linear protrusion of the lower incisors, improvement in the maxillomandibular relationship and in molar relationship, as well as a significant decrease in the overjet and overbite and an inhibition of the vertical development of the upper incisors. The study demonstrated no significant changes in maxillary growth during the evaluation period. It was concluded from these results that the effects of the Eruption Guidance Appliance during this time period were mostly dentoalveolar, with a smaller, but significant, skeletal effect.

Cephalometry↗