Regional Nodal Recurence as a Prognostic Factor in Patients Kept on Observation for cT1-T2 Oral Squamous Cell Carcinomas of Tongue: A Meta-Analysis of 11,973 Patients.

The surgical management of the clinically node negative neck in T1-T2 early oral tongue squamous cell carcinoma (OTSCC) has been the topic of debate since few decades. As the occult cervical lymph node metastasis is considered to be the primary prognostic factor in early OTSCC, this meta-analysis has been carried out to find the risk of regional nodal recurrence on patients kept under observation than those who have underwent Elective neck dissection (END). The articles were electronically retrieved from Ovid Medline, PubMed, Cochrane and Scholar for comparison of Observation versus END in early OTSCC. The search strategy identified 35 relevant review articles from April 1979 to April 2020 from different search engines. A total of 11,973 patients from 30 retrospective analyses, 4 prospective and 1 randomized control trials were included in this meta-analysis. Overall test revealed (OR: 13.02 95% CI 1.360-17.154) with t test 2.382 and p value 0.023 which is statistically significant and showed that END significantly reduced the risk of regional nodal recurrence. This meta-analysis finds that there is statistically significant relationship when END was performed which reduced the risk of regional nodal recurrence as seen in patients kept on Observation thereby affecting the Overall survival (OS) rate.

Lingual Bracket Systems with Self Etching Primers- An In Vitro Study to Evaluate Shear Bond Strength.

AIM: To evaluate the shear bond strength of orthodontic lingual bracket systems bonded to extracted premolar teeth (Reliance self-etching primer, Clearfil Protect Bond) and self-etching primer (Clearfil SE Bond) Materials and methods: A total of 160 extracted human first premolars were selected and divided into four groups of 10 for each bracket system to be used with four different primers. Each sample was then embedded in an acrylic block, till the coronal portion. Instron testing machine model LR LOYD 50 K was used for testing the shear bond strength. RESULTS: The results obtained, suggested that all the primers had clinically acceptable shear bond strength with all the bracket system considered in the study. However, there were statistically significant differences in the shear bond strength in intergroup comparisons. CONCLUSION: The Reliance Self-Etching primer showed the highest bond strength with Alias lingual bracket system by Ormco, followed by clearfil protect bond, clearfil SE bond, and transbond, with the Alias lingual bracket system in the same order. CLINICAL SIGNIFICANCE: This study was initiated to understand the shear bond strength of self-etching primer and its efficacy over the conventional primer, which will be of use to the clinician while selecting the primer for bonding of the bracket systems and overcome debonding of brackets encountered during the treatment progress.

Comparison of Shear Bond Strength of New Self-etching Primer with Conventional Self-etching Primers: An In-vitro Study.

BACKGROUND: In the past few years, there has been a major research drive to increase bond strength between dental materials and dental hard tissue and to reduce the associated demineralization around fixed orthodontic appliances. Thus, a recent approach is to incorporate an antibacterial agent into the primer to reduce the demineralization and enhance bond strength. The objective of this study was: (1) To evaluate the shear bond strength of orthodontic preadjusted edgewise appliance brackets bonded to extracted premolar teeth with antimicrobial self-etch primer (Reliance self-etching primer, Clearfil Protect Bond) and self-etching primer without antimicrobial agent (Clearfil SE bond). (2) To compare the mean shear bond strength values of the tested materials to conventional self-etching primer Transbond Plus. MATERIALS AND METHODS: A total of 125 extracted human premolar teeth were randomly divided into five groups of 25 teeth each. Each sample was embedded in an acrylic block of polymethyl meth acrylate resin till coronal portion. Instron testing machine model LR LOYD 50 K was used for testing the shear bond strength of individual samples. RESULTS: The results of the study showed that all five groups had adequate clinically acceptable bond strength. In intergroup comparison, there was statistically significant difference in bond strength of Reliance self-etching primer, Promt L pop, Clearfil Protect Bond, clearfil SE bond and Transbond Plus. CONCLUSION: Reliance self-etching primer showed highest bond strength, followed by Clearfil Protect Bond, clearfil SE bond, and Transbond Plus. Clearfil Protect Bond primer containing methacryloxy dodecyl pyridium bromide have been demonstrated to kill Streptococcus mutans within a short time of contact and also exhibits an inhibitory effect on the growth of bacteria on its surface.