DENTAL DEFECTS WITH SUBGINGIVAL EXTENSION: A RESTORATIVE CONUNDRUM

There are situations where the subgingival margin of the restoration are unavoidable such as subgingival caries, fractures and resorption. The subgingival cavity margin creates various challenges during operative procedure and can affect periodontal health .Several restorative materials have been tried to restore cavities with subgingival margin. This paper will review the current approaches to the treatment of teeth involving root surfaces with caries, fractures, resorption and developmental defect with an objective to discuss clinical problems associated with deep subgingival margins and to have clear strategies of treatment approach in such situations.

A Review of Silorane and Methacrylate Based Composites and Effective Factors on Microleakage of them

Introduction: An important disadvantage of current dental resin composites is their polymerization shrinkage and production of microleakage. This shrinkage can cause tooth sensitivity, marginal discoloration, and secondary caries. The objective of this study was to review the effective factors on microleakage of methacrylate and silorane composites and compare them with each other. This reviewed article was compiled and searched on library sources and Google scholar, Pubmed, ISI of science database, using the key words “Microleakage, Siloran-Based Composite, Methacrylate-Based Composite, Retentive Groove, Light Curing Technique,” from 1984 -2019. Although it is not yet definitely clear, which methods of layering techniques (oblique, vertical, split) are more suitable, it seems that the layering technique has advantage over the bulkythat can effective in decreasing the shrinkage caused by polymerization and the resulting microlaekage. It can also be concluded that silorane base composites have less shrinkage, but some factors such as cavity type, cavity extent, cavity margin distance to CEJ, type of silorane base bonding system are also involves in their microleakage. It seems the presence of retention grooves in the cavities seems useful, because it increases the bonding area and mechanical retention as well as decreases the marginal shrinkage due to polymerization and the resulting microleakage. Conclusion: Finally, it can be said that microleakage cannot be stopped completely, and more studies, especially clinical studies, should be conducted to show the effects of these cases clinically.

Cavity Margin Status Is an Independent Risk Factor for Local-Regional Recurrence in Breast Cancer Patients Treated with Neoadjuvant Chemotherapy Before Breast-Conserving Surgery

The objection of this study is to investigate whether the cavity margin (CM) status has different predictive efficacy for local-regional recurrence (LRR) in patients who have received or have not received neoadjuvant chemotherapy (NAC) before breast-conserving surgery. We identified 61 patients who received NAC before breast-conserving surgery. A nonrandomized unmatched cohort of 295 patients without history of receiving NAC were also included in this study. Clinicopathological features and follow-up data were abstracted and analyzed. Patients in the NAC-treated group had more advanced diseases when compared with patients in the non NAC-treated group. With a median follow-up of 42 months, the LRR-free survival rate of patients with positive CMs was significantly lower than that of patients with negative CMs in the NAC-treated group. This distinction was not observed in the nonNAC-treated group. Univariate and multivariate analysis revealed that positive CM was the only independent predictive factor for LRR in the NAC-treated group but not in nonNAC-treated patients. CM status had different predictive efficacy for LRR in different settings. Association between CM status and LRR was observed in NAC-treated patients rather than nonNAC-treated patients. More extensive surgical treatment might be needed in NAC-treated patients when their CMs are positive.

Dosimetry study of a phase II multiple-dose intracavitary administration of 131I-TM601 in adult patients with recurrent high-grade glioma

e13006 Background: Postoperative radiotherapy for glioma has been shown to improve survival with increased radiation doses. Dose escalation of external beam radiotherapy or brachytherapy is limited by normal brain radionecrosis. Radiolabeled targeting molecules can deliver localized radiation to tumor and reduce normal brain radionecrosis. TM601, or synthetic Chlorotoxin, is a peptide derived from scorpion venom that specifically binds to tumor cells. Here we report dosimetry results of an imaging sub-study of a phase II trial, in which weekly doses of 131I-TM601 were infused into surgically created tumor resection cavities for 3 or 6 weeks. Methods: Five out of 76 patients treated in a phase II trial were imaged after receiving 1, 3, or 6 doses of 40 mCi/0.8 mg 131I-TM601 intracavitarily. For each imaging study, 5 sequential SPECT images (1–168 hour) were registered with MRI to determine the 131I-TM601 radiation dose to the 2-cm tumor cavity margin. Five sequential body scans were also acquired to determine 131I-TM601 radiation dose to extra-cranial organs. Results: 131I-TM601 is a rapidly penetrating and clearing radiolabeled peptide. The median residual activity in the cavity at 7 days post injection was 8.4%. Median radiation dose to the cavity margin was 121 cGy/mCi and ranged 52- 338 cGy/mCi in 5 subjects. The median coefficient of variation (intra-patient inter-fraction) for the 2-cm margin dose was 14.7% and ranged 7.1–18.9%. Median tumor cavity volume was 11.4 mL, and ranged 5.2 - 35.5 mL. There was no observed correlation between the 2-cm margin dose and the cavity volume. Median radiation dose to thyroid, kidneys, red marrow, and body was 8.3, 1.3, 0.4, and 0.6 cGy/mCi, respectively. Conclusions: Radiation dose ratio for 2-cm cavity margin-to-normal tissues was quite high. While intra-patient reproducibility was relatively good, cumulative effect of the residual activity was only meaningful within a week. These results support the multi-dose fractionation scheme for 131I-TM601 to minimize normal tissue toxicity, including radiation necrosis, and extend continuous irradiation to clinical or sub-clinical residual tumor cells after surgery. [Table: see text]