INTRODUCTION: Orthodontic treatment often involves planned tooth movement within the confined spaces of the alveolar bone trough. Tooth movement within the alveolar trough may be limited by thin labial and lingual cortical plates. Moving lower incisors beyond the mandibular symphysis dimensions may result in damage to roots and alveolar bone.4 Aim and objective: The aim of the study was to evaluate limitation of treatment in different skeletal patterns due to mandibular symphysis dimension in order to evaluate limitations of tooth movement within the confines of the mandibular alveolar trough.The objective was to determine the mandibular symphysis dimensions in subjects with differing skeletal patterns. DESIGN: The design was a retrospective, cross-sectional study. METHODS: A sample of 180 pre-treatment lateral cephalometric radiographs of black South African subjects were stratified into three groups based on their skeletal classification. Each Class was further divided into equal numbers of males and females. Descriptive statistics, Student's t-test, ANOVA test and Pearson correlation coefficient were used to analyse the data and p-values of <0.05 were considered statistically significant. RESULTS: Subjects with skeletal Class I pattern had a greater LA compared to subjects with skeletal Class II pattern. Subjects with skeletal Class I pattern had a greater LH and LA in females than in males. Subjects with skeletal Class III pattern had greater LH in males than in females.

INTRODUCTION: Anterior open bite (AOB) malocclusion presents as lack of vertical overlap of anterior teeth. It is viewed to be unaesthetic and may affect speech and mastication It develops due to the interaction of hereditary and environmental etiological factors and these usually affect the vertical growth of the face. This study describes the vertical changes of South African black people presenting with AOB. AIMS AND OBJECTIVES: The aim was to determine skeletal morphological features of patients with AOB malocclusion. DESIGN: The design was a retrospective, cross-sectional study. MATERIALS: Archived pre-treatment lateral cephalographs of 181 patients who consulted between 2007 and 2014 were divided into four groups: control group of 62 patients with skeletal Class I pattern without AOB; test groups of patients with AOB (119) divided into 35 Class I, 43 Class II, and 41 Class III malocclusions. Records of each group were divided according to gender. Descriptive statistics, the Pearson correlation coefficient, t-test and. Wilcoxon test were employed to analyze the data, and p values of <0.05 were considered statistically significant. RESULTS AND CONCLUSIONS: Patients with AOB had a larger vertical facial pattern in all classes of malocclusion. Males presented with larger Sn-GoGn angles than females. The PFH/AFH ratio was lower across all classes of malocclusion compared to the control group.

INTRODUCTION: Flexure of the cranial base plays a crucial role in the study of the craniofacial complex. The outcome of orthodontic treatment can be predicted if growth and flexure of the cranial base is understood. AIM: The aim of this study was to determine the relationship between cranial base flexure and sagittal jaw relationships in a sample of Black South African subjects. METHODOLOGY: A sample of pre-treatment lateral cephalograms of 300 patients with a mean age of 17.72 years was divided into three equal groups according to gender and skeletal classification. Age differences were tested using the Kruskal-Wallis test. Cranial base flexure differences were first tested using ANOVA and further evaluated using Student's f-test. RESULTS: Age distribution was similar in all three in all classes of sagittal jaw relationship. Class II subjects demonstrated a significantly larger cranial base flexure when compared with Class I and Class III subjects respectively. CONCLUSION: In this study sample, a larger cranial base flexure is a feature of Class II sagittal jaw relationship whilst both Class I and Class III sagittal jaw relationships are associated with smaller cranial base flexures. There were no significant differences between the Class I and Class III sagittal jaw relationship samples.

INTRODUCTION: Cephalometric norms have been established for the McNamara analysis for different age, racial and ethnic groups AIM: To establish McNamara cephalometric norms for a sample of Black South African adults and to compare with Caucasian norms METHODS: Thirty lateral cephalograms of a sample of eligible untreated Black adult subjects was retrieved from archives in the Department of Orthodontics at the Medunsa Oral Health Centre. They were traced and digitized using Dolphin Imaging® computer software. The McNamara analysis was performed. The one sample f-test was performed to compare study values with McNamara norms. The two sample f-tests were used to determine statistical differences between the data for genders RESULTS: The mean age of the study subjects was 24 years (SD=3.9). Two-thirds of the linear measurements were significantly higher than the McNamara norms. The angular measurements of female subjects were significantly higher than McNamara's reference values As regards gender differences, almost two-thirds of male linear measurements were higher than females, and the differences were statistically significant in half of the measurements. In contrast, though all higher, female angular measurements showed no statistically significant differences. CONCLUSION: Gender and racial differences exist in cephalometric norms measured using the McNamara analysis

ABSTRACT The objective of this study was to identify the species and characterize the genetic relationships among mycoplasma isolates from commercial layer hen flocks using 16S-23S rDNA intergenic spacer region (IGSR) sequencing. Twenty-one isolates were obtained from samples collected from commercial layer flocks in four Brazilian states: São Paulo, Minas Gerais, Rio de Janeiro and Espírito Santo. The isolates were recovered from the São Paulo, Rio de Janeiro and Espírito Santo states. Eleven isolates were originated from tracheal swabs, five from shell gland swabs and five from ovary fragment collection. The 16S-23S rDNA IGSR of isolates were amplified by PCR, and the obtained products were subsequently sequenced. The consensus of each isolate was compared to the available sequences using Nucleotide BLAST® to determine the mycoplasma species. A phylogenetic analysis of the Mycoplasma gallisepticum (MG) sequences was performed. Pairwise analyses showed homologies of 99% to 100% with the previously characterized sequences listed in GenBank®. Four Mycoplasma gallinaceum were isolated from three flocks and seven M. pullorum isolates were obtained from a single flock. The other 10 isolates were all identified as MG and were obtained from four flocks. The 16S-23S rDNA IGSR sequencing was a good method to identify Mycoplasma species isolated from field samples, providing fast and reliable results at relatively low costs. The results were also satisfactory for the single-locus sequence typing of MG isolates.

BACKGROUND: Temporary Skeletal Anchorage Devices (TSADs) are small titanium screws that are inserted through the gingival or palatal mucosa into supporting bone to form an independent rigid anchor unit or may be tied to adjacent teeth to enhance their anchorage capability. On completion of orthodontic treatment the orthodontist is easily able to unscrew and remove the screws. OBJECTIVE: To conduct a survey on the clinical use of TSADs amongst South African orthodontists. MATERIALS AND METHOD: The method consisted of a structured survey questionnaire which was sent to 110 South African orthodontists registered on the South African Society of Orthodontists database in 2013. RESULTS: Forty six orthodontists completed the survey, a response rate of 41.81%. Of these respondents, 63.04% used TSADs, and of those, 58.62% placed TSADs themselves while the remainder referred to maxillo-facial surgeons, and to a lesser extent, to periodontists, for placement. The majority (72.41%) loaded TSADs immediately. TSADs were used mostly to provide anchorage when teeth were moved mesially (52%) or distally along the arch. CONCLUSIONS: South African orthodontists have adopted a cautious approach to the use of TSADs. Training in the placement and the clinical application of TSADs should be incorporated in the curriculae of postgraduate orthodontics.