ABSTRACT
INTRODUCTION: The main reason for seeking orthodontic treatment for Class II malocclusions is aesthetic improvement. Growth modification treatment procedures offer better results for a patient with significant potential growth. AIM: The aim of this cephalometric clinical study was to distinguish skeletal and dental corrections on skeletal class II division I growing subjects with Twin Block therapy (TB) and the changes were assessed using SO-analysis by Pancherz. MATERIALS AND METHODS: Strict diagnostic protocol viz. growing individuals with horizontal growth pattern, skeletal class II due to retrognathic mandible with positive VTO, bilateral class II molar relation, minimal crowding in either arch or overjet more than 5mm was used. Out of 28 selected cases,17 patients received TB therapy and 11 patients were maintained as control group. Standard removable TB appliances with lower incisor capping were delivered to treatment group. The horizontal advancement was about 8mm and 2-3mm vertical opening between the upper and lower central incisors were maintained for all the cases. The mean time interval between the initial (T1)and post treatment (T2) cephalograms of Twin-Block group was 11 month,with a range of 8 month to 13 month. In the control group, the mean time interval between the first (C1)and second (C2) cephalometric films was 12 month,with a range of 10 month to 14 month.T1and T2 cephalograms were traced and S-O analysis was used to segregate dental and skeletal effects. STATISTICAL ANALYSIS: SPSS software was used for statistical analysis. RESULTS: Skeletal Changes: In this study, the mean movement of maxilla was 0.67mm which represents significant restriction of forward maxillary growth in contrast to control groups. Dental Changes: In this study the maxillary molars appear to move distally with a mean value of 0.13mm. Comparing this to the movement of maxillary jaw base itself, maxillary distal movement of molar is less. But still it contributes to Class II correction. CONCLUSION: The overjet reduction and molar relation correction are more skeletal in nature.
ABSTRACT
BACKGROUND: Dental caries is essentially a process of diffusion and dissolution. If the aspect of dissolution can be curtailed some degree of prevention can be achieved. AIMS: The present study was carried out to evaluate and compare the effect of Er:YAG laser and Co2 laser irradiation combined with acidulated phosphate fluoride treatment on in vitro acid resistance of human enamel. DESIGN: An in vitro study was carried out on 30 human premolars to evaluate the enamel's acid resistance using an atomic emission spectrometry analysis. MATERIALS AND METHODS: A total of 60 enamel specimens were prepared from 30 human premolars and were randomly assigned to 6 groups: (1) Untreated (control); (2) 1.23% acidulated phosphate fluoride (APF) gel application alone for 4 min; (3) Er:YAG laser treatment alone; (4) Co2 laser treatment alone; (5) Er:YAG laser + APF gel application; (6) Co2 laser + APF gel application. The specimens were then individually immersed in 5 ml of acetate buffer solution (0.1 mol/L, pH 4.5) and incubated at 37°C for 24 h, and the acid resistance was evaluated by determining the calcium ion concentration using the atomic emission spectrometry. STATISTICAL ANALYSIS: An ANOVA model was constructed (P value of 0.05), followed by Tukey's test for multiple pair wise comparisons of mean values. RESULTS: Significant differences were found between the control group and the test groups (P < 0.001). CONCLUSIONS: Combining acidulated phosphate fluoride with either Er:YAG or Co2 laser had a synergistic effect in decreasing the enamel demineralization more than either fluoride treatment or laser treatment alone.
