Faculty Bibliography

The onset of the Coronavirus 2019 (COVID-19) pandemic has challenged the worldwide healthcare sector, including dentistry. The highly infectious nature of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus and risk of transmission through aerosol generating procedures has profoundly impacted the delivery of dental care services globally. As dental practices with renewed infection control strategies and preventive measures are re-opening in the "new normal" period, it is the responsibility of healthcare professionals to constantly analyze new data and limit the spread of COVID-19 in dental care settings. In the light of new variants of SARS-CoV-2 rapidly emerging in different geographic locations, there is an urgent need to comply more than ever with the rigorous public health measures to mitigate COVID-19 transmission. The aim of this article is to provide dental clinicians with essential information regarding the spread of SARS-CoV-2 virus and protective measures against COVID-19 transmission in dental facilities. We complied and provided guidance and standard protocols recommended by credible national and international organizations. This review will serve as an aid to navigating through this unprecedented time with ease. Here we reviewed the available literature recommended for the best current practices that must be taken for a dental office to function safely and successfully.

OBJECTIVE:is associated with one or more particular comorbidities. STUDY DESIGN/METHODS:or DH lesion to a control patient who had a history of dentoalveolar surgery with uneventful healing and no history of antiresorptive therapy. Comorbidity data included medical conditions and smoking. RESULTS:and DH than in controls [M(SD) = 1.94 (1.2) and 2.0 (1.3) vs 1.26 (0.89); both P < .001]. CONCLUSIONS:and DH.

PURPOSE: There is considerable controversy over the treatment of medication-related osteonecrosis of the jaw (MRONJ) and growing interest and debate related to the timing, type, technique, and goals of surgical intervention. The specific aim was to evaluate the predictive value of fluorodeoxyglucose (FDG) positron emission tomography (PET) with computed tomography (CT) on healing outcomes in patients undergoing surgery for MRONJ of the mandible. MATERIALS AND METHODS: A retrospective cohort study of 31 patients with 33 MRONJ lesions of the mandible who had undergone surgery using FDG PET-CT was conducted. Data were collected on FDG uptake patterns, healing, follow-up, demographics, lesion characteristics, antiresorptive therapy, and adjunctive therapy. Panoramic and periapical radiographs were used to identify non-restorable teeth and PET-CT images were used to identify sequestra and FDG uptake. Above the mandibular canal, surgery consisted of marginal resection or debridement of clinically involved bone and exposure of clinically uninvolved bone identified by FDG uptake. Below the mandibular canal, mobile segments of bony sequestra were removed, but areas of clinically uninvolved bone with FDG uptake were not. Patients who did not heal underwent segmental resection and reconstruction with rigid fixation and a local or regional soft tissue flap or free fibular flap. The primary predictor variable was the FDG uptake pattern for each patient. The outcome variable was postoperative healing defined by mucosal closure without signs of infection or exposed bone at the time of evaluation. RESULTS: Two risk groups were identified based on FDG uptake pattern. The low-risk group, type A, included 22 patients with activity limited to the alveolus, torus, and basal bone superior to the mandibular canal. The high-risk group, type B, included 11 patients with type A FDG activity with extension inferior to the mandibular canal. Treatment of type A MRONJ lesions was more successful than treatment of type B MRONJ lesions (100 vs 27%; P < .001). Seven of the type B failures were successfully retreated by segmental resection and reconstruction (1 patient refused further treatment). CONCLUSION: These results showed that low-risk FDG PET-CT findings predicted successful healing with surgery above the mandibular canal. In contrast, high-risk FDG findings were associated with a greater than 50% risk of failure for treatment that extended below the mandibular canal. Although these failures suggest that FDG uptake indicates infected tissue, further research is needed to identify which high-risk patients are most likely to benefit from a conservative treatment protocol.

Biphasic calcium phosphate (BCP) bioceramics have been successfully applied in a broad variety of presentation forms and with different ratios of hydroxyapatite (HA) and beta-tricalcium phosphate (beta-TCP). BCPs have been loaded with stem cells from different origins for bone tissue engineering purposes, but evidence of stem cell behavior on different compositions (various HA/beta-TCP ratios) and physical features of BCPs is limited. We compared the adhesion, proliferation, viability and osteogenic potential of human mesenchymal stem cells (MSCs) on granular BCPs with equal HA/beta-TCP ratio of diverse particle sizes and on porous blocks which had different chemical compositions. In addition, the osteogenic differentiation of MSCs was compared to adipose-derived (ADSC) and dental pulp (DPSC) stem cells, as well as to pre-osteoblasts on a particulate BCP. MSCs growing on granular BCPs demonstrated increased number as compared to MSCs growing on blocks. Cells proliferated to a greater extent on small granular BCPs, while large granular BCPs and blocks promoted cell differentiation. Surprisingly, the expression of genes involved in osteogenesis was upregulated in MSCs on bioceramics in basal medium which indicates that BCPs may have osteoinductive potential. This was confirmed with the upregulation of osteochondrogenic markers, at different time points, when stem cells from various tissues were grown on the BCP. This study demonstrates that BCPs, depending on their physical features and chemical composition, modulate stem cell behavior, and that stem cells from different origins are inherently distinct in their gene expression profile and can be triggered toward osteochondrogenic fate by BCPs.

Bacterial biofilms have emerged as potential critical triggers in the pathogenesis of bisphosphonate (BP)-related osteonecrosis of the jaw (ONJ) or BRONJ. BRONJ lesions have shown to be heavily colonized by oral bacteria, most of these difficult to cultivate and presents many clinical challenges. The purpose of this study was to characterize the bacterial diversity in BRONJ lesions and to determine host immune response. We examined tissue specimens from three cohorts (n=30); patients with periodontal disease without a history of BP therapy (Control, n=10), patients with periodontal disease having history of BP therapy but without ONJ (BP, n=5) and patients with BRONJ (BRONJ, n=15). Denaturing gradient gel electrophoresis of polymerase chain reaction (PCR)-amplified 16S rRNA gene fragments revealed less bacterial diversity in BRONJ than BP and Control cohorts. Sequence analysis detected six phyla with predominant affiliation to Firmicutes in BRONJ (71.6%), BP (70.3%) and Control (59.1%). Significant differences (P<0.05) in genera were observed, between Control/BP, Control/BRONJ and BP/BRONJ cohorts. Enzyme-linked immunosorbent assay (ELISA) results indicated that the levels of myeloperoxidase were significantly lower, whereas interleukin-6 and tumor necrosis factor-alpha levels were moderately elevated in BRONJ patients as compared to Controls. PCR array showed significant changes in BRONJ patients with downregulation of host genes, such as nucleotide-binding oligomerization domain containing protein 2, and cathepsin G, the key modulators for antibacterial response and upregulation of secretory leukocyte protease inhibitor, proteinase 3 and conserved helix-loop-helix ubiquitous kinase. The results suggest that colonization of unique bacterial communities coupled with deficient innate immune response is likely to impact the pathogenesis of ONJ.International Journal of Oral Science advance online publication, 8 August 2014; doi:10.1038/ijos.2014.46.

PURPOSE: Imaging is important to identify subclinical changes and for treatment planning in patients with osteonecrosis of the jaw (ONJ) exposed to antiresorptive therapy. The aim of this study was to compare the findings at radiography with those at fluorodeoxyglucose (FDG) positron emission tomography (PET) with computed tomography (CT) for patients with ONJ related to antiresorptive therapy. MATERIALS AND METHODS: A cross-sectional retrospective analysis of patients with clinically identified ONJ lesions of the mandible was performed. Two imaging modalities were evaluated for each patient: plain radiography (ie, panoramic or periapical) and FDG PET/CT with 1-mm sections. Outcome variables for the radiographic findings were osteolytic and osteosclerotic bone changes. Outcome variables for FDG PET/CT images were localization of FDG uptake. Maximum standard uptake values (SUVmax) of abnormal FDG jaw uptake were recorded, in addition to the mean SUV of the contralateral normal mandible, and used to calculate the target-to-background ratio. Radiographic changes and FDG uptake were classified as local (ie, corresponding to exposed cortical bone) or diffuse (ie, local changes and changes extending beyond the margins of exposed bone) for each imaging technique. Local and diffuse changes detected by each imaging modality were described and the difference in detection was compared with the McNemar test. RESULTS: Twenty-three patients with 25 clinically identified ONJ lesions were analyzed using radiography and FDG PET/CT. Differences were found in how radiography and FDG PET/CT detect local and diffuse changes associated with ONJ. Radiography showed local changes in 17 patients (68%), diffuse changes in 3 patients (12%), and no changes in 5 patients (20%), whereas FDG PET/CT imaging showed local changes in 17 patients (68%) and diffuse changes in 8 patients (32%). The McNemar test indicated that FDG PET/CT imaging was less likely to miss a lesion (P < .001). Mean SUVmax was 6.59, and the mean target-to-background ratio was 5.37. CONCLUSION: The results of this study show that FDG PET/CT detects local and diffuse metabolic changes that may not be represented by plain radiography for patients with ONJ related to antiresorptive therapy. The target-to-background ratio allowed the discrimination between ONJ lesions and background changes. Future studies are necessary to determine whether FDG PET/CT can determine risk and facilitate management of ONJ.

PURPOSE: Osteonecrosis of the jaw (ONJ) has been reported to be associated with patients receiving bisphosphonate (BP) therapy. There are many reports that suggest that the time of exposure to BPs is a significant risk factor for ONJ and that the greatest risk occurs after dentoalveolar surgery. The aim of this study was to retrospectively investigate the duration of BP therapy and related events before the onset of ONJ based on an intravenous (IV) or oral route of administration. MATERIALS AND METHODS: We conducted a retrospective cohort study of patients referred to our institution to identify the onset of ONJ based on the exposure to BP therapy and associated triggers (ie, dentoalveolar surgery or spontaneous occurrence) based on the route of BP administration. Demographic data (ie, age, gender, and race), medical diagnosis related to BP therapy, and information as to whether the BP therapy was continued at the time of ONJ diagnosis were also collected. RESULTS: We reviewed the records for 114 patients with a history of ONJ. We divided patient cohorts by route of BP administration, with 76 patients having a history of IV BP therapy and 38 patients having a history of oral BP therapy. The overall onset of ONJ was earlier in the IV BP group (median, 3 years) compared with the oral BP group (median, 5 years). There was no statistical difference in the duration to occurrence of ONJ associated with dental extraction compared with spontaneous occurrence for both the IV and oral BP groups. CONCLUSIONS: The median onset of ONJ for patients undergoing IV BP therapy occurs earlier than the median onset for patients undergoing oral BP therapy, and there was no difference in onset occurring spontaneously and after dental extraction. The significance of these findings suggests that patients who receive IV BP therapy should be closely evaluated after the initiation of BP therapy. The lack of evidence suggesting greater onset after dental extraction may provide clinical support for dentoalveolar surgery that is indicated for patients with a history of BP therapy. Research focusing on the clinical circumstances and physiologic events during early antiresorptive therapy may provide insight as to the critical risk factors.