Development and validation of a formula for objective assessment of cervical vertebral bone age.

BACKGROUND AND AIM: Determination of skeletal maturity and bone age from cervical vertebrae has been well documented. Most methods described use subjective evaluation of morphological characteristics of cervical vertebrae and may be prone to variability and error. A few objective methods have also been developed, specific for certain populations and genders. The aim of this study was to establish and validate an objective method to determine cervical vertebral bone age from lateral cephalometric radiographs, for Asian South Indian patients of both genders. METHODS: Ninety boys and 90 girls between 9 and 15 years of age were recruited, and their lateral cephalograms were taken. Using measurements made from the third and fourth cervical vertebrae, a formula to determine cervical vertebral bone age was derived using stepwise regression analysis. To validate the formula, a separate sample of 30 boys and 30 girls was chosen, and hand-wrist radiographs and lateral cephalograms were obtained. Cervical vertebral bone age (CVBA) was determined by applying the formula derived. Bone age was also calculated using the Tanner-Whitehouse 3 method. The bone ages determined by both methods were compared to each other and chronological age, using one-way ANOVA, Tukey's post hoc analysis, and Pearson's correlation coefficient. RESULTS: The formulae derived in the current study to determine CVBA differed for both genders. No statistically significant difference was found between CVBA, bone age derived by the Tanner-Whitehouse 3 method, and chronological age for both boys (p value = 0.425) and girls (p value = 0.995). A moderate to strong positive correlation was found between CVBA, bone age, and chronological age. CONCLUSION: The formulae derived in this study were validated and are reliable for objectively determining cervical vertebral bone age and skeletal maturation from lateral cephalograms for Asian South Indian patients of both genders.

Comparative Evaluation of Two Bis-GMA Based Orthodontic Bonding Adhesives - A Randomized Clinical Trial.

INTRODUCTION: Of the various orthodontic bonding materials, orthofix is a fairly new entrant into this field. This material was exclusively introduced for orthodontic bonding purposes; however, the application of this material for orthodontic purpose has not been scientifically evaluated so far. AIM: The aim of the present study was to evaluate by an in-vivo double blinded split mouth rando mized clinical trial, the overall bond failure rates of two Bis-GMA based composite materials namely Transbond XT and Orthofix. MATERIALS AND METHODS: Thirty three participants who fulfilled the inclusion criteria were randomly allocated by lottery method into two groups. Group A participants had maxillary right and the mandibular left quadrants bonded using Orthofix and the remaining quadrants were bonded using Transbond XT. In Group B, the quadrants were reversed. Both groups were followed for a period of six months and were reviewed every 3-4 weeks. If a bond failed, the details were recorded and the duration of treatment before each breakage was calculated. Data were analyzed using Independent t-test and chi-square test. (p< 0.05) at 90% power. RESULTS: The overall bond failure rate for 263 brackets was 2.7% for Orthofix and 3.6% for Transbond XT. The mean esitmated survival time was 221.58 days for Transbond XT and for Orthofix was 220.07 days. The difference between these mean values were statistically insignificant (p>0.05). Similarly, failure rates of the anterior and posterior segment were compared and no difference was observed between the groups (p>0.05). The maxillary and mandibular teeth were compared and more failures were found in the mandibular teeth among both the groups but they were not statistically significant (p>0.05). CONCLUSION: The overall bond failure rate and mean survival time for Transbond XT was similar to Orthofix with no statistically significant difference.

SBS vs Inhouse Recycling Methods-An Invitro Evaluation.

INTRODUCTION: In today's world of economic crisis it is not feasible for an orthodontist to replace each and every debonded bracket with a new bracket- quest for an alternative thrives Orthodontist. The concept of recycling bracket for its reuse has evolved over a period of time. Orthodontist can send the brackets to various commercial recycling companies for recycling, but it's impractical as these are complex procedures and require time and usage of a new bracket would seem more feasible. Thereby, in-house methods have been developed. The aim of the study was to determine the SBS (Shear Bond Strength) and to compare, evaluate the efficiency of in house recycling methods with that of the SBS of new brackets. MATERIALS AND METHODS: Five in-house-recycling procedures-Adhesive Grinding Method, Sandblasting Method, Thermal Flaming Method, Buchman method and Acid Bath Method were used in the present study. Initial part of the study included the use of UV/Vis spectrophotometer where in the absorption level of base of new stainless steel bracket is compared with the base of a recycled bracket. The difference seen in the UV absorbance can be attributed to the presence of adhesive remnant. For each recycling procedure the difference in UV absorption is calculated. New stainless steel brackets and recycled brackets were tested for its shear bond strength with Instron testing machine. Comparisons were made between shear bond strength of new brackets with that of recycled brackets. The last part of the study involved correlating the findings of UV/Vis spectrophotometer with the shear bond strength for each recycling procedure. RESULTS: Among the recycled brackets the Sandblasting technique showed the highest shear bond strength (19.789MPa) and the least was shown by the Adhesive Grinding method (13.809MPa). CONCLUSION: The study concludes that sand blasting can be an effective choice among the 5 in house methods of recycling methods.