Comparative Evaluation of Effect of Micro-Osteoperforation and Mechanical Vibration on Rate of Orthodontic Tooth Movement in Young Adults With Bimaxillary Protrusion.

AIM: To evaluate and compare the rate of orthodontic tooth movement and root resorption by micro-osteoperforation (MOP) and mechanical vibration in young adults with bimaxillary protrusion. METHOD: Twenty patients having class I bimaxillary protrusion who required all first premolar extraction were allocated into two groups MOP (Group A) and mechanical vibration (Group B), with a 1:1 allocation ratio. After leveling alignment MOP was performed on either side of the arch, and vibration was applied on the contralateral side 20 mins per day. Canines were retracted with nickel-titanium coil springs, and Alginate impressions were taken every four weeks till 4 months. RESULT: The mean rate of retraction of canines of Group A was more than Group B. There was a statistically significant difference between Group A and Group B. (p=0.0120) Conclusion: The mean rate of retraction of canines treated by MOP was 1.15 mm per 4 weeks, and by mechanical vibration, 0.8mm per 4 weeks.

The effect of pressure changes during simulated diving on the shear bond strength of orthodontic brackets.

INTRODUCTION: This study investigated the effect of pressure variations to which divers are subjected on shear bond strength of orthodontic brackets bonded to teeth with resin modified glass ionomer cement (RMGIC) or composite resin. METHODS: Eighty extracted premolars were randomly divided into two groups. Group 1: orthodontic brackets were bonded with RMGIC. Group 2: orthodontic brackets were bonded with composite resin. Each group was further divided into two subgroups. Subgroup A: The samples were kept at sea level pressure (101 kPa). Subgroup B: The samples were pressurised once from 101 kPa to 405 kPa for five minutes, then depressurised to 101 kPa. Shear bond strength was then measured. RESULTS: Shear bond strength of brackets bonded with RMGIC in the simulated diving group was significantly less than that of ambient pressure group (P = 0.019), while no significant difference was found between the simulated diving group and ambient pressure group for brackets bonded with resin cement (P = 0.935). At ambient pressure, there was no significant difference between shear bond strength of brackets bonded with RMGIC and composite resin (P = 0.83). In simulated diving conditions, there was a statistically significant difference between shear bond strength of brackets bonded with the RMGIC and composite (P = 0.009). CONCLUSIONS: Pressure changes during scuba diving may have an adverse effect on the retention of brackets bonded with RMGIC. Using composite resin for bonding brackets appears to be good strategy for patients such as divers who will be exposed to pressurised environments.

Evaluation of YouTube Videos as a Source of Information About Oral Self-examination to Detect Oral Cancer and Precancerous Lesions.

Objectives: The aim of this study was to investigate quality, reliability, and comprehensiveness of YouTube videos about oral self-examination to detect oral cancer and precancerous lesions and to assess whether the source, duration, quality, reliability, and/or comprehensiveness of videos influence their visibility and popularity. Materials and Methods: Videos on YouTube were searched using eight keywords similar to oral self-examination. The first 100 videos for each search term were included. Strict inclusion and exclusion criteria were adhered to, and videos were assessed for quality, reliability, and comprehensiveness. Upload date, views, likes, dislikes, duration, and source of the videos were noted. Viewing rate and interaction index were calculated for each video. Results: A total of 800 videos were analyzed, 24 of which met the inclusion criteria. Majority of videos (87%) were uploaded by the healthcare group. The visibility, quality, reliability, and comprehensiveness were higher in videos uploaded by the healthcare group when compared with the non-healthcare group, but not at a level of statistical significance. The mean interaction index score of the non-healthcare group was found to be higher than the healthcare group, with statistically significant difference. Duration of videos showed an impact on the comprehensiveness of the videos. Conclusion: There are relatively few videos on oral self-examination on YouTube, and most do not have satisfactory quality, reliability, and comprehensiveness. There is a potential to increase public awareness about oral self-examination by utilizing this tool. Videos with complete and accurate information regarding oral self-examination must be uploaded to YouTube, which is currently an important source of information for the general public.

Provisional Crown Dislodgement during Scuba Diving: A Case of Barotrauma.

Changes in ambient pressure, for example, during flying, diving, or hyperbaric oxygen therapy, can lead to barotrauma. Although it may seem that this issue was neglected in dental education and research in recent decades, familiarity with and understanding of these facts may be of importance for dental practitioners. We report the case of a patient who experienced barotrauma involving dislodgement of a provisional crown during scuba diving. Patients who are exposed to pressure changes as a part of their jobs or hobbies and their dentists should know the causes of barotrauma. In addition, the clinician must be aware of the possible influence of pressure changes on the retention of dental components.

The effect of pressure changes during simulated diving on the pull out strength of glass fiber posts.

BACKGROUND: Scuba diving is one of the fastest growing sports in the world. The objective of this study was to evaluate the effect of pressure variations to which divers are exposed on the pull out strength of glass fiber post luted with different cements. MATERIALS AND METHODS: In this in vitro study, 120 extracted, single-rooted lower premolars were endodontically treated. They were randomly divided into six groups and restored using the glass fiber post (Ivoclar Vivadent AG) and the following luting agents: Zinc phosphate, conventional glass ionomer, resin reinforced glass ionomer, resin cement with etch-and-rinse adhesive, resin cement with self-etching adhesive, and self-adhesive resin cement. Each group was randomly divided into two equal subgroups, one as a control, and the other to be used experimentally. After 7 days of storage, experimental groups were pressure cycled. The force required to dislodge each post was recorded in Newton (N) on Universal testing machine (Star Testing System) at a crosshead speed of 1 mm/min. Data were statistically analyzed using the ANOVA and Student's t-test (P < 0.001). RESULTS: The pull out strength of posts cemented with zinc phosphate and conventional glass ionomer in pressure cycle group was significantly less than their control group. Although, no significant difference was found between pressure cycle and control group using resin reinforced glass ionomer cement and resin cements. CONCLUSION: Dentist should consider using resin reinforced glass ionomer or resin cement, for the cementation of glass fiber post, for the patients such as divers, who are likely to be exposed to pressure cycling.

The effect of environmental pressure changes on the retentive strength of cements for orthodontic bands.

OBJECTIVES: The purpose of this study was to evaluate the effect of environmental pressure changes on the retentive strength of orthodontic bands cemented with conventional glass ionomer cement or resin-modified glass ionomer cement. MATERIALS AND METHODS: Stainless steel bands were cemented to 80 extracted first and second molars in two equal groups comprising conventional glass ionomer cement and resin-modified glass ionomer cement. Each group was randomly divided into two sub-groups of 20 samples each, one sub-group to act as a control, and the other to be used experimentally. After seven days of storage, the experimental groups were subjected to simulated dives to 405 kPa [corrected] for 3 minutes, 15 times in a pressure pot, after which the force required to deband was tested using a universal testing machine. The data were statistically analysed using Student's t-tests, significance being assumed at P < 0.001. RESULTS: The retentive strength of bands cemented with conventional glass ionomer in the pressure-cycled group was statistically significantly less than that in the control group. No statistically significant difference in strength was found between the two groups cemented with resin-modified glass ionomer. CONCLUSIONS: This study showed that the retentive strength of bands cemented with conventional glass ionomer is reduced after pressure cycling. We suggest that dentists should consider using resin-modified glass ionomer cement for cementing orthodontic bands for patients who are divers and thus likely to be exposed to raised-pressure cycling.