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Assessment of patients for orthognathic surgery.

Rapid advances in orthognathic surgery now allow the clinician to treat severe dentofacial deformities that were once only manageable by orthodontic camouflage. These cases were often compromised with unacceptable facial esthetics and unstable occlusal results. Over the past 25 years, there have been numerous improvements in technology and the surgical management of dentofacial deformities. These progressions now allow more predictable surgical outcomes, which ensure patient satisfaction. Not all patients are candidates for surgical treatment; therefore, patient assessment and selection remains paramount in the process of diagnosing and treatment planning for this type of irreversible treatment. The inclusion of patients in the decision-making process increases their awareness and acceptance of the final result. The past three decades indicate an increased usage of orthodontic treatment by both children and adults. Patient demographic profiles for severe occlusal and facial characteristics are presented in an effort to understand the epidemiological factors of malocclusion and predict the population's need for this service.

Adult↗

The long-term benefits of orthodontic treatment.

OBJECTIVE: This study aimed to evaluate post-treatment changes at least five years out of retention in a cohort of 100 consecutively started patients treated by a postgraduate student in a UK orthodontic department. DESIGN: Analysis of study models using recognised occlusal indices. Setting Patients initially treated at Newcastle Dental Hospital were recalled for record collection. MATERIALS AND METHODS: Study models and clinical photographs were taken for each patient attending for post-retention records. Weighted Peer Assessment Rating (PAR) Index and Index of Orthodontic Treatment Need (IOTN) scores were recorded for cases at the beginning, end and at least 5 years post-retention. Main outcome measures Post-treatment changes were evaluated using PAR Index and IOTN to evaluate extent and likelihood of change and to compare treatment modalities. RESULTS: Seventy-eight patients attended for post-retention records. Overall PAR reduction immediately post-treatment was 68.6% and at a mean of 6.5 years post-retention was 55.5%. Dual arch fixed appliance treatments achieved the greatest reduction in PAR score, and maintained the reduction beyond the retention period better than other treatment modalities. Eighty-four per cent of the cohort still had some demonstrable improvement after a mean of 6.5 years post-retention. There was a residual need for treatment in 8% of cases on aesthetic grounds and in 24% of cases on dental health grounds. CONCLUSIONS: Occlusal deterioration after orthodontic treatment is almost universal. Dual arch fixed appliance treatment provides the best post-treatment and post-retention result.

Cohort Studies↗

CASES--clinical audit; scenarios for evaluation and study.

CASES, an audit and continuing education programme, evaluated aspects of current orthodontic practice and allowed orthodontists to identify areas where their practice differed from regional and national results. Evaluation of the CASES programme verified its value in audit and continuing education and the authors hope it will encourage similar projects in other disciplines too.

Adolescent↗

An anatomical and radiographic study of medial depression of the human mandibular ramus.

OBJECTIVES: To determine the prevalence of the medial depression of mandibular ramus (MDMR) in dry human mandibles and in clinical panoramic radiographs and to compare the prevalence in dentoskeletal deformities with Angle Class I occlusion. METHODS: Two hundred and fifty-one dry skulls and three groups of patients were used for this study: Group 1 consisted of 1358 panoramic radiographs from a general population, Group 2, 426 radiographs from individuals with Angle class I occlusion and Group 3283 individuals with dentoskeletal deformities. The prevalence of MDMR was determined in the skulls and each group and the shape from the radiographs alone. RESULTS: The prevalence of MDMR in dry mandibles was 33.9% (bilateral in 13.1% and unilateral in 20.8%). MDMR was found in 276 radiographs (20.3% - Group 1 - bilateral in 40% and unilateral in 59.5%). MDMR was more common in Group 3 compared with Group 2 (chi(2)=35.98 P<0.01). A triangular MDMR was the most frequent (39.7%). CONCLUSION: MDMR is a relatively common finding in panoramic radiographs. Patients with dentoskeletal deformities have a higher prevalence of MDMR and this should be taken into consideration if orthognathic surgery is proposed.

Adolescent↗

Malocclusion and facial morphology is there a relationship? An epidemiologic study.

The purpose of this study is to examine associations between facial morphology and malocclusion, and to test for sexual dimorphism in such relationships. The sample of 500 subjects is studied by roentgenographic cephalometry, using the Facial Height Ratio (FHR) of Jarabak as the mensurational approach to describe craniofacial morphology. Significant findings are: Neutral pattern is dominant in Class I and Class II1 malocclusions. Hypodivergent pattern is dominant in Class II2 and Class III malocclusions. The majority of females demonstrate a neutral pattern, whereas the majority of males demonstrate a hypodivergent pattern. Sexual dimorphism in pattern is greatest in Class II1 and Class III. Males show a greater tendency toward prognathism, while females tend toward orthognathism and retrognathism. Mean values of all linear measurements in males are larger than in females. Relatively strong correlations are found between facial height ratio and ramus height, gonial angle, lower gonial angle, mandibular plane angle, occlusal/mandibular plane angle, palatal/mandibular plane angle, Frankfurt/mandibular plane angle, S-N-B, Y-axis angle, and the sum of the saddle + articular + gonial angles.

Cephalometry↗

A new cephalometric parameter to aid in dental base relationship analysis.

The cephalometric literature is rich with different craniofacial analyses. However, since these analyses are only descriptive for the clear skeletal discrepancies and somewhat handicapped for borderline cases, an investigation was designed to assess the dental base relationship in the human lateral skull cephalostat radiograph. A number of existing measurements were reviewed, and a new measurement, based upon anatomical points which could prove to be more reliable, was introduced.

Adult↗

Skeletal jaw relationships: a quantitative assessment using elliptical Fourier functions.

Elliptical Fourier functions (EFF) were generated for the boundary outlines of the hard tissue craniofacial complex including the maxilla, mandible, and cranial base in order to quantitatively describe adult patients (n = 98) who were initially classified into nine skeletal groups by a combination of conventional cephalometric measures and clinical judgement. The mean residual fit of the EFF-predicted points and the original digitized data for the individual subjects ranged from .42 mm to .61 mm with a mean of .52 mm suggesting an accurate fit. Visual inspection of the individual plots confirmed this. Predicted classifications from a step-wise discriminant analysis based on EFF amplitudes were compared with the original classifications. The discordance rates for A-P and vertical plane classification were 21% and 13% respectively with an overall discordance rate of 33%. In general, a cluster analysis using EFF amplitudes did not identify clusters very similar in membership to the original groups; however, it was marginally successful in identifying members of the more severe groups and, like discriminant analysis, appeared to be more sensitive to vertical morphological differences. The overall lack of agreement between classifications and clusters based on EFF amplitudes and the original classifications may indicate that traditional skeletal categories such as those used in this study do not actually represent discrete groups.

Adolescent↗

The relationship between bruxism and occlusal factors among seven- to 19-year-old Turkish children.

The aim of this study was (1) to investigate the relationship between occlusal factors and bruxism among 965 Turkish subjects (472 boys and 493 girls) with a mean age of 12.8 years (range, seven to 19 years); and (2) to identify possible sex differences between girls and boys. This sample was divided into two groups of bruxers or nonbruxers based on a clinical examination and self-reports. The examiner recorded the Angle molar classification bilaterally, severity of anterior crowding, existence of anterior and posterior crossbite, open and deep bite, functional shift, and excessive overjet. The relationships between occlusal factors and bruxism and sex differences between boys and girls were evaluated with chi-square analysis (chi2) using the SPSS software package. The results showed that bruxism was diagnosed in 12.6% of all subjects. The evaluation of the findings indicated that no statistically significant relationships were determined between bruxism and occlusal factors. No sex differences were found between occlusal factors in relation to bruxism. The prevalence of bruxism in boys and girls was similar, and no statistically significant differences were found. It is concluded that none of the occlusal factors seem to play a role in the development of bruxism. However, additional longitudinal studies with larger samples need to be conducted to determine if there is any relationship between occlusal factors and bruxism.

Adolescent↗

Dental arch dimensions in the mixed dentition: a study of Italian children born in the 1950s and the 1990s.

The objective of this study was to compare the dental arch dimensions in the mixed dentition in two modern samples living in the same geographic area and separated by almost 35 years. A group of 83 subjects (39 boys and 44 girls) born between 1953 and 1959 (mean age: eight years and three months +/-15 months for the boys and seven years and 11 months +/-12 months for the girls) were compared with a group of 84 subjects (38 boys and 46 girls) born between 1990 and 1998 (mean age: eight years and eight months +/-12 months for the boys and eight years and four months +/-11 months for the girls). Measurements were taken on dental casts for posterior and anterior arch segments, intermolar and intercanine width, and mesiodistal size of incisors. The available anterior space in both arches and the posterior and anterior transverse dimensions were calculated. Groups were compared using a nonparametric test (Mann-Whitney U-test) for independent samples (P < .05). Results show that both boys and girls of 1990s showed significantly smaller maxillary intermolar width when compared with 1950s. Posterior transverse interarch discrepancy was significantly minor in girls of 1990s. The present population has a greater probability of developing a malocclusion as a consequence of the secular trend toward the reduction of the width of the upper arch.

Case-Control Studies↗

Objective measures as indicators for facial esthetics in white adolescents.

The objective of this study was to examine the contribution of objective measures representing anterior-posterior and vertical characteristics, dental esthetics, or their combination that are used in daily orthodontic practice in the assessment of facial esthetics. A panel of 78 laymen evaluated facial esthetics of 32 boys and 32 girls, stratified over the four Angle classes, on a visual analogue scale. The relation between the objective parameters and facial esthetics was evaluated by backward multiple regression analysis. Dental esthetics as expressed by the Aesthetic Component of the Index of Orthodontic Treatment Need (AC/IOTN) appeared to be the most important indicator for facial esthetics. A new parameter, the "horizontal sum" was found to be a reliable variable for the anterior-posterior characteristics of the patient. Addition of this newly defined parameter to the AC/IOTN improved the prognostic value from 25% to 31%.

Adolescent↗

Relationship between the flow of bolus and occlusal condition during mastication--computer simulation based on the measurement of characteristics of the bolus.

The purpose of the present study was to clarify the relationship between the flow of a bolus and occlusal condition during mastication. First, the characteristics of a bolus under mastication was measured in subjects having different occlusal conditions. Secondly, the flow of a bolus between the upper and lower first molars under mastication was simulated using finite element non-linear dynamic analysis. Measurement of the elasticity of the bolus clarified the phenomenon of its communition. The measurement of the viscosity of the bolus clarified the phenomenon of its mixing with saliva. In addition, a relationship between the elasticity and the viscosity of the bolus at the point of just before swallowing was investigated. The flow of the bolus under mastication was revealed to vary according to the occlusal condition. These results suggest a close relationship between the occlusal condition, the flow of the bolus and its characteristics.

Adult↗

Prevalence of malocclusion among Latino adolescents.

Although numerous studies have documented malocclusion in various ethnic groups in the United States, the prevalence of malocclusion in the Latino population is not well known. The Latino population may be the largest minority group in the United States by the year 2004. This study analyzes the occlusion of 507 Latino adolescents between the ages of 12 and 18 years. More than 93% of the subjects demonstrated some form of malocclusion. The distribution of malocclusion patterns is presented and contrasted with data published for other ethnic groups. Information about the prevalence and types of malocclusion in the Latino population should be of interest to general dental practitioners and specialists.

Adolescent↗

Considerations for orthognathic surgery during growth, part 2: maxillary deformities.

The growing patient can present to the clinician with significant dentofacial deformities that require surgical correction. In some cases, certain functional, esthetic, and psychosocial factors may necessitate early surgical intervention. Although there is extensive literature on the effects and stability of orthognathic surgical correction of maxillary deformities in adults, the same is not true for the pediatric and adolescent growing patient. Not much is known about the predictability of orthognathic surgical procedures performed during growth or the effects such procedures have on subsequent facial growth. There is always the possibility that secondary corrective procedures may be required after the initial corrective surgery. This article presents recommendations based on available research and personal clinical experience in surgical correction of maxillary deformities in growing patients. The common maxillary dentofacial deformities, age considerations, and surgical alternatives and sequencing are presented. The treatment of mandibular deformities is addressed in Part 1 of this article.

Adolescent↗

Considerations for orthognathic surgery during growth, part 1: mandibular deformities.

Management of the growing patient with mandibular dentofacial deformities presents a unique and challenging problem for orthodontists and surgeons. The surgical procedures required for correction of the deformity may affect postsurgical growth and dentofacial development. Further, facial growth may continue postoperatively and negate the benefits of surgery performed, resulting in treatment outcomes that are less than ideal. From individual patient characteristics, the type of deformity, and the indications for early surgical intervention, it is possible to effectively treat many cases during growth. A thorough understanding of facial growth patterns is essential, and each case needs to be evaluated individually. Surgery is often undertaken with the expectation that additional treatment, including more surgery, may be required after the completion of growth. The material presented here is based on the available research and the senior author'ss clinical experience of more than 25 years in the correction of mandibular deformities in the growing patient. Advantages and disadvantages of specific surgical techniques for correction of common mandibular deformities and pertinent age and surgical considerations are discussed. The material should be viewed as a general outline that provides broad guidelines for management of these patients. The management of maxillary deformities will be discussed in Part 2 of this article.

Adolescent↗

An appraisal of the Peer Assessment Rating (PAR) Index and a suggested new weighting system.

The PAR Index was developed to measure treatment outcome in orthodontics. Validity was improved by weighting the scores of some components to reflect their relative importance. However, the index still has limitations, principally due to the high weight assigned to overjet. Difficulties also arise from the application of one weighting system to all malocclusions, since occlusal features vary in importance in different classes of malocclusion. The present study examined PAR Index validity using orthodontic consultant assessments as the 'Gold standard' and clinical ranking of occlusal features and statistical modelling to derive a new weighting system, separate for each malocclusion class. Discriminant and regression analyses were used to derive new criteria for measuring treatment outcome. As a result a new and more sensitive method of assessment is suggested which utilizes a combination of point and percentage reductions in PAR scores. This was found to have better correlations with the 'Gold standard' than the PAR nomogram.

Dental Occlusion↗