Professor Dileep Sharma

This scoping review was carried out to evaluate the important role Australian university-based dental teaching clinics and dental students might have in promoting oral cancer awareness in their patients. Four Online database (PubMed, OVID, Scopus and Emcare) were searched for studies that assessed oral cancer awareness amongst patients attending Australian university-associated (teaching) clinics. A total of five articles were retrieved for full-text analysis. All studies showed significant variation in patient awareness and understanding regarding the principal risk factors associated with oral cancer development. Smoking was predominantly identified as a significant risk factor, but alcohol consumption was less frequently recognized as relevant. Non-healing ulceration was most commonly identified as a symptom of concern, whilst red and/or white mucosal patches were infrequently recognized as potentially malignant conditions. Our review confirms that a significant lack of patient awareness regarding oral cancer risk and the signs /symptoms of early malignancy or potentially malignant disease exist in patients attending dental teaching clinics. Important opportunities exist to involve dental students proactively in raising oral cancer awareness, delivering smoking cessation interventions and safe alcohol consumption advice to their patients. Incorporation of established health educational models might deliver effective support for such student-delivered patient education.

The objective of this paper was to investigate the published evidence regarding effects of cannabinoids (natural and synthetic) on post-operative and/or out-of-office pain management in patients suffering from orofacial pain that presents in the dental setting. Three online databases (Ovid (MEDLINE), PubMed (MEDLINE), Scopus) were searched (July 2021). Additional studies were sought through grey literature searching (Cochrane Library Trials and ClinicalTrials.gov) and hand-searching the reference lists of included articles. All studies that analysed cannabinoid products and pain management of conditions that present in the general or specialist dental setting in the English language were included. Of the five articles included, one reported a significant effect on temporomandibular disorder pain relief using a topical cannabidiol formulation compared to a placebo. Four articles reported no significant effects of cannabinoids for pain management across various orofacial pain conditions. Although one study reported a positive effect, insufficient evidence exists to support a tangible clinical benefit of cannabinoids in managing orofacial pain, further research is recommended to investigate the benefits of cannabinoids¿ use. © 2022 Australian Dental Association.

Objective: To evaluate the effect of routinely used physical decontamination methods on the surface characteristics of zirconia implants and subsequent ability of bacteria to adhere in vitro. Background: Physical decontamination methods commonly used in peri-implantitis therapy and routine implant maintenance can potentially alter zirconia implant surfaces. Methods: Acid-etched zirconia discs were instrumented with titanium curette (TC), plastic curette, air abrasive device, ultrasonic scaler (US) with stainless steel tip. Following instrumentation, surface topography, and surface elemental composition was analyzed using 3D-laser scanning microscopy and energy-dispersive X-ray spectroscopy, respectively. Subsequently, plaque biofilm was cultured on zirconia discs for 48 h and bacterial adhesion assessed using a turbidity test and scanning electron microscopy. Results: A significant difference in surface roughness was observed between the US and control group (p¿< 0.05). The US and TC caused gray surface discolouration on zirconia discs due to deposition of metallic residue as confirmed by X-ray spectroscopy. No significant difference in bacterial adhesion was noted among all treatment groups (p¿> 0.05). Conclusion: TC and US with stainless steel tips should be used with caution due to deposition of metallic residue on the surface. Air abrasive devices and plastic curettes caused minimal surface alterations and are, therefore, safer for zirconia implant decontamination.

Background: To analyze the fracture resistance of zirconia implants within the anterior region and evaluate whether zirconia¿zirconia implants can be a viable alternative to titanium im-plants. Methods: Four online databases (Cochrane Library, Ovid, PubMed, and Scopus) were searched for the period of January 2011 to July 2021. All studies that analyzed the in vivo clinical outcome of two-piece implants in the anterior region in English language were included. Results: The search strategy identified 242 studies. Of these studies, three studies were included for qualitative synthesis based on the pre-determined eligibility criteria. The results showed that there is significant difference in biological results, fractal behavior and other complications between one-piece and two-piece zirconia implants. Two-piece zirconia implants demonstrated favorable longevity and success rates within anterior maxillary in short-term trials. Conclusions: Although factors in-volved in fractures have been identified¿sandblasting, implant diameter, occlusal load, age and implant coating¿there is limited quantitative assessment to gauge the fracture resistance of two-piece zirconia implants. Hence, further research with long-term clinical evidence is required.

COVID-19, the global pandemic, has significantly interrupted the provision of oral health care to many individuals. This study aims to evaluate patients¿ attitudes to and perceptions of dental visits in the COVID-19 pandemic and assess if socio-economic status influences their perception of risk associated with dental visits. Patients attending the dental clinic were invited to participate in this study by completing a questionnaire administered in August 2021. Composite indicators for access, attitude, perception and socio-economic status were created based on subsets of questions. A total of 247 completed questionnaires were obtained. Analysis was performed with the perception, attitude and access indicators against the socio-economic status indicator. This study found that there is a statistically significant difference between socio-economic groups and their attitudes and perceptions around dental health care services in the current COVID-19 pandemic. Individuals from lower socio-economic status groups were less influenced by the pandemic. Participants from higher socio-economic status groups were found to be more cautious around COVID-19 and its risks.

Background/Aim: Machine learning (ML) models are often modelled to predict cancer prognosis but rarely consider spatial factors in a region. Hence this study explored machine learning algorithms utilising Local Government Areas (LGAs) in Queensland, Australia to spatially predict 3- and 5-year prognosis of oral cancer patients and provide clinical interpretability of the predicted outcome made by the ML model. Patients and Methods: Data from a total of 3,841 oral cancer patients were retrieved from the Queensland Cancer Registry (QCR). Synthesizing minority oversampling technique together with edited nearest neighbours (SMOTE-ENN) was used to pre-process unbalanced datasets. Five ML models: logistic regression, random forest classifier, XGBoost, Gaussian Naïve Bayes and Voting Classifier were trained. Predictive features were age, sex, LGAs, tumour site and differentiation. Outcomes were 3- and 5-year overall survival of patients. Model performances on test set were evaluated using area under the curve and F1 scores. SHapley Additive exPlanations (SHAP) method was applied to the best performing model for model interpretation of the predicted outcome. Results: The Voting Classifier was the best performing model with F1 score of 0.58 and 0.64 for 3- and 5-year overall survival, respectively. Age was the most important feature in the Voting Classifier in 3- and 5-year prognosis prediction. LGAs at diagnosis was the top 3 predictive feature for both 3- and 5-year models. Conclusion: The Voting Classifier demonstrated the best overall performance in classifying both 3- and 5-year overall survival of oral cancer patients in Queensland. SHAP method provided clinical understanding of the predictive features of the Voting Classifier.

This review sheds light on the recent published scientific evidence relating to the use of professionally delivered local antimicrobial agents (LA's). The review also analyses drug delivery systems available to date and provides an update on the latest scientific evidence about the benefits, limitations, and clinical results obtained by use of local drugs in the treatment of periodontal disease. The search strategy revealed randomized controlled trials (RCTs) that compared the efficacy of adjunctive LA's to mechanical therapy alone. Based on the available evidence gathered from this review, we can infer that the use of local antimicrobial agents in conjunction to scaling and root debridement (SRD) delivers significant benefits in periodontal therapy and it is a useful aid, avoiding many of the side effects that systemic antibiotic therapy may involve. Local drug delivery (LDD) is an efficient and effective means of delivering drugs based on the evidence presented in the review. The authors of this review would suggest the use of local antimicrobials in cases of localized periodontitis or individual areas that do not respond to the usual mechanical therapy alone. This review summarizes the current use of local drug delivery in periodontal management ensuring that the general practitioners are able to choose an appropriate local antimicrobial.

The present systematic review evaluates the safety of placing dental implants in patients with a history of antiresorptive or antiangiogenic drug therapy. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed. PubMed, Cochrane Central Register of Controlled Trials, Scopus, Web of Science, and OpenGrey databases were used to search for clinical studies (English only) to July 16, 2019. Study quality was assessed regarding randomization, allocation sequence concealment, blinding, incomplete outcome data, selective outcome reporting, and other biases using a modified Newcastle-Ottawa scale and the Joanna Briggs Institute critical appraisal checklist for case series. A broad search strategy resulted in the identification of 7542 studies. There were 28 studies reporting on bisphosphonates (5 cohort, 6 case control, and 17 case series) and 1 study reporting on denosumab (case series) that met the inclusion criteria and were included in the qualitative synthesis. The quality assessment revealed an overall moderate quality of evidence among the studies. Results demonstrated that patients with a history of bisphosphonate treatment for osteoporosis are not at increased risk of implant failure in terms of osseointegration. However, all patients with a history of bisphosphonate treatment, whether taken orally for osteoporosis or intravenously for malignancy, appear to be at risk of ¿¿implant surgery-triggered¿¿ medication-related osteonecrosis of the jaw (MRONJ). In contrast, the risk of MRONJ in patients treated with denosumab for osteoporosis was found to be negligible. In conclusion, general and specialist dentists should exercise caution when planning dental implant therapy in patients with a history of bisphosphonate and denosumab drug therapy. Importantly, all patients with a history of bisphosphonates are at risk of MRONJ, necessitating this to be included in the informed consent obtained before implant placement.

About half of the world¿s population and 80% of the world¿s biodiversity can be found in the tropics. Many diseases are specific to the tropics, with at least 41 diseases caused by endemic bacteria, viruses, parasites, and fungi. Such diseases are of increasing concern, as the geographic range of tropical diseases is expanding due to climate change, urbanization, change in agricultural practices, deforestation, and loss of biodiversity. While traditional medicines have been used for centuries in the treatment of tropical diseases, the active natural compounds within these medicines remain largely unknown. In this review, we describe infectious diseases specific to the tropics, including their causative pathogens, modes of transmission, recent major outbreaks, and geographic locations. We further review current treatments for these tropical diseases, carefully consider the biodiscovery potential of the tropical biome, and discuss a range of technologies being used for drug development from natural resources. We provide a list of natural products with antimicrobial activity, detailing the source organisms and their effectiveness as treatment. We discuss how technological advancements, such as next-generation sequencing, are driving high-throughput natural product screening pipelines to identify compounds with therapeutic properties. This review demonstrates the impact natural products from the vast tropical biome have in the treatment of tropical infectious diseases and how high-throughput technical capacity will accelerate this discovery process.

Background: Actinic cheilitis, herpes labialis and lip cancer are relatively common conditions presenting on the lips associated with exposure to periods of sun exposure and thereby ultraviolet radiation. Objective: This systematic review aimed to determine the efficacy of the application of sunscreen-containing lip-protecting agents (LPA) in the prevention of actinic cheilitis (AC), recurrent herpes labialis (RHL) and lip cancer (LC). Methods: This review was conducted in accordance with the PRISMA guidelines and registered with the PROSPERO database. A literature search was conducted using SCOPUS, Google Scholar, Medline (Ovid), Pubmed, CINAHL, Cochrane Library databases and manual search using search terms actinic cheilitis (AC), recurrent herpes labialis (RHL) and lip cancer (LC) along with lip protecting agents and their variations as keywords. A total of 1,567 papers were yielded. Of them, nine studies were eligible for qualitative data synthesis. Results: Nine articles (3 AC, 5 RHL, 1 LC) were deemed eligible and thus selected for qualitative synthesis. Three studies on AC identified approximately 21.7% lower prevalence of lesions when some form of lip protection was used. Eighty percent of studies on RHL identified that the application of LPA is effective in preventing RHL. Subjects who applied LPA more than once daily only had half the risk of having LC compared to those who applied once daily. Conclusion: This review of randomised controlled trials (RCTs) and observational studies supports the use of LPA as an effective method in preventing lip-associated lesions. Further, RCTs and observational studies should aim at determining a definitive LPA application regime and optimal SPF strength to prevent lip-associated lesions. This systematic review was registered with the International Prospective Register of Systematic Reviews (PROSPERO): Registration Number-CRD42020177484. https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020177484.

Purpose: Peri-implantitis therapy and implant maintenance are fundamental practices to enhance the longevity of zirconia implants. However, the use of physical decontamination methods, including hand instruments, polishing devices, ultrasonic scalers, and laser systems, might damage the implant surfaces. The aim of this systematic review was to evaluate the effects of physical decontamination methods on zirconia implant surfaces. Methods: A systematic search was conducted using 5 electronic databases: Ovid MEDLINE, PubMed, Scopus, Web of Science, and Cochrane. Hand searching of the OpenGrey database, reference lists, and 6 selected dental journals was also performed to identify relevant studies satisfying the eligibility criteria. Results: Overall, 1049 unique studies were identified, of which 11 studies were deemed suitable for final review. Air-abrasive devices with glycine powder, prophylaxis cups, and ultrasonic scalers with non-metal tips were found to cause minimal to no damage to implant-grade zirconia surfaces. However, hand instruments and ultrasonic scalers with metal tips have the potential to cause major damage to zirconia surfaces. In terms of laser systems, diode lasers appear to be the most promising, as no surface alterations were reported following their use. Conclusion: Air-abrasive devices and prophylaxis cups are safe for zirconia implant decontamination due to preservation of the implant surface integrity. In contrast, hand instruments and ultrasonic scalers with metal tips should be used with caution. Recommendations for the use of laser systems could not be fully established due to significant heterogeneity among included studies, but diode lasers may be the best-suited system. Further research¿specifically, randomised controlled trials¿would further confirm the effects of physical decontamination methods in a clinical setting.

A promising approach to improve the poor antibacterial properties of dental composite resins has been the addition of metal oxide nanoparticles into the resin matrix. This systematic review aimed to determine whether the addition of zinc oxide nanoparticles (ZnO-NPs) improves the antibacterial properties of direct dental composite resins. This review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and registered with the PROSPERO database: CRD42019131383. A systematic literature search was conducted using the following databases: Medline (Ovid), the Cochrane Library, SCOPUS, CINAHL, Web of Science, Trove, Google Scholar, World Cat, and OpenGrey. The initial search retrieved 3178 results, which were then screened against inclusion and exclusion criteria, resulting in a total of four studies that were eligible for qualitative synthesis within this review. All the included studies were in vitro non-randomized post-test design experimental studies. A lack of congruity in the results obtained from these studies that used different tests to evaluate antibacterial activity was evident. Although some studies demonstrated a significant improvement of antibacterial properties in composites containing at least 1% ZnO-NPs (wt %), they are unlikely to present any clear clinical advantage due to the short lifetime of observed antibacterial properties.

The anti-angiogenic effects of bisphosphonates have been hypothesized as one of the major etiologic factors in the development of medication-related osteonecrosis of the jaw (MRONJ), a severe debilitating condition with limited treatment options. This study evaluated the potential of a gelatine-hyaluronic acid hydrogel loaded with the angiogenic growth factor, vascular endothelial growth factor (VEGF), as a local delivery system to aid in maintaining vascularization in a bisphosphonate-treated (Zoledronic Acid) rodent maxillary extraction defect. Healing was assessed four weeks after implantation of the VEGF-hydrogel into extraction sockets. Gross examination and histological assessment showed that total osteonecrosis and inflammatory infiltrate was significantly reduced in the presence of VEGF. Also, total vascularity and specifically neovascularization, was significantly improved in animals that received VEGF hydrogel. Gene expression of vascular, inflammatory and bone specific markers within the defect area were also significantly altered in the presence of VEGF. Furthermore, plasma cytokine levels were assessed to determine the systemic effect of locally delivered VEGF and showed similar outcomes. In conclusion, the use of locally delivered VEGF within healing extraction sockets assists bone healing and prevents MRONJ via a pro-angiogenic and immunomodulatory mechanism.

Objectives: To assess if using potassium iodide (KI) immediately after application of silver diamine fluoride (SDF) significantly reduces the staining of tooth structure. Data source and selection: Four online databases (OVID, Scopus, PubMed and Google Scholar) were searched (June 2019). Additional studies were sought through grey literature search and hand searching the reference list of included articles. All studies that analysed the effect of KI on SDF staining of tooth structure with access to full text in English language were included. Data synthesis: Of the six articles included in the review, five reported stain reduction in the teeth treated with application of KI to carious tooth structure following the application of SDF while one article reported no significant beneficial effect on reducing staining, when compared to SDF alone. Of the materials selected to restore SDF¿+¿KI treated teeth, resin-modified glass ionomer was found to produce the lightest results, followed by glass ionomer cement and composite resin. An in vivo case report also revealed some staining after six months, even with SDF¿+¿KI treatment. Conclusions: Although some studies reported a positive effect, insufficient evidence exists supporting a tangible clinical benefit of SDF¿+¿KI treatment on the tooth staining, mainly due to methodical variations within the current literature.

Background/Aim: This survey-based study aims to explore the clinicalmanagement protocols of followed by Australian periodontists in relation to peri-implant diseases. Materials and Methods: A five-part online questionnaire was developed and administered through email. Descriptive statistics were used for analysis,with the univariate associations between a categorical outcome and the variables evaluated using Pearson's Chi-squared test. Results: The survey yielded 99 responses, resulting in a response rate of 41.8%. Most participants were male and aged 35-44 years. More than a quarter of practitioners had been placing implants for 6-10 years and almost two-fifths of practitioners placed 1-10 implants per month. The estimated prevalence of peri-implant mucositis and peri-implantitis in the general Australian population was 47% and 21%, respectively. Practitioners reported using systemic antibiotics to manage peri-implant mucositis (7%) and (72%) peri-implantitis lesions, with a combination of amoxicillin and metronidazole. Most common treatment modalities were oral hygiene instructions, nonsurgical debridement and antimicrobial gel/rinse. Surgical debridement and systemic antibiotics were also often used for peri-implantitis treatment. Practitioners preferred a 3-month clinical follow-up and 6-month radiographic evaluation. Furthermore, three-quarters of practitioners rated their management as moderately effective, although upwards of nine-tenths expressed the need for further training and awareness. Conclusion: This study confirms a significant use of empirical treatment modalities due to lack of standard therapeutic protocol. However, some approaches followed by the specialists may provide a basis to formulate a therapeutic protocol for peri-implant disease management.

Background: This systematic review aims to assess the current evidence on the efficacy of surgical and non-surgical debridement techniques in the treatment of peri-implantitis lesions without the use of any antimicrobials. Method: Five electronic databases (MEDLINE, Pubmed, Scopus, CINAHL and Cochrane) were used, alongside hand searches, to find relevant articles. Full-text articles that were randomised controlled trials, published in the English language from 2011 onwards without pre-operative, peri-operative and post-operative antibiotic usage were included. The study was conducted according to the latest Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-P protocols, the latest Cochrane Risk of Bias tool and each investigated intervention was evaluated using the grading of recommendation, assessment, development and evaluation (GRADE) system. Results: The search yielded 2718 results. After initial screening, 38 full-text articles were assessed for eligibility. From these, 11 studies satisfied all inclusion criteria. These 11 articles described six non-surgical and five surgical debridement therapies. Most articles were classified as having either a high risk of bias or presenting with some concerns. Small sample sizes, in combination with this risk of bias, meant that all interventions were adjudged to be of either low or very low quality of evidence. Conclusion: While all investigated modalities displayed some sort of efficacy, this review suggests that a surgical approach may be best suited to treating peri-implantitis lesions in the absence of antibiotic therapy. Despite this weak indication, further research is required in this field.

Background: This study compared the in vitro response of a mouse pre-osteoblast cell line on a novel sandblasted zirconia surface with that of titanium. Material and Methods: The MC3T3-E1 subclone 4 osteoblast precursor cell line was cultured on either sandblasted titanium (SBCpTi) or sandblasted zirconia (SBY-TZP). The surface topography was analysed by three-dimensional laser microscopy and scanning electron microscope. The wettability of the discs was also assessed. The cellular response was quantified by assessing the morphology (day 1), proliferation (day 1, 3, 5, 7, 9), viability (day 1, 9), and migration (0, 6, 24 h) assays. Results: The sandblasting surface treatment in both titanium and zirconia increased the surface roughness by rendering a defined surface topography with titanium showing more apparent nano-topography. The wettability of the two surfaces showed no significant difference. The zirconia surface resulted in improved cellular spreading and a significantly increased rate of migration compared to titanium. However, the cellular proliferation and viability noted in our experiments were not significantly different on the zirconia and titanium surfaces. Conclusions: The novel, roughened zirconia surface elicited cellular responses comparable to, or exceeding that, of titanium. Therefore, this novel zirconia surface may be an acceptable substitute for titanium as a dental implant material.

Purpose: The purpose of this study was to investigate the effects of celecoxib and ibuprofen on the proliferation, viability, and migration of MC3T3-E1 cells cultured on titanium surfaces. Materials and Methods: MC3T3-E1 cells were cultured on sandblasted titanium disks and allocated to one of the following six groups: (a) control (untreated); (b) celecoxib (5 µM and 10 µM); (c) ibuprofen (5 µM and 10 µM); and (d) prostaglandin E2 (10 µM). Proliferation of attached cells was assessed over 9 days using an alamarBlue assay. A trypan blue exclusion test was conducted to assess cell viability; the relative percentages of live and dead cells were quantified using a hemocytometer over 2 days. A Boyden-Chamber Assay was utilized to assess cell migration over 3 days. Results: The proliferation of cells treated with any intervention was not significantly different than that of the untreated group throughout the treatment period. However, celecoxib and ibuprofen significantly decreased the percentage of viable cells in a dose-dependent manner. Specifically, celecoxib (10 µM) and ibuprofen (5 µM and 10 µM, respectively) on day 1 and celecoxib (10 µM) on day 2 showed significantly higher percentages of dead cells compared to the untreated cells. There was a significant increase in migration of cells treated with ibuprofen (5 µM) compared to untreated cells on day 1; however, the migration of cells treated with any of the interventions was not significantly different from that of untreated cells on day 3. Conclusion: Nonsteroidal anti-inflammatory drugs at therapeutic doses did not significantly affect osteoblast proliferation and migration. However, higher dosages of celecoxib (10 µM) significantly reduced the cell viability and therefore can potentially affect the process of osseointegration.

The contribution of the local stem cell niche to providing an adequate vascular framework during healing cannot be overemphasized. Bisphosphonates (BPs) are known to have a direct effect on the local vasculature, but their effect on progenitor cell differentiation is unknown. This in vitro study evaluated the effect(s) of various BPs on the differentiation of human placental mesenchymal stem cells (pMSCs) along the endothelial lineage and their subsequent functional and morphogenic capabilities. pMSC multipotency was confirmed by successful differentiation into cells of both the osteogenic and endothelial lineages, as demonstrated by positive Alizarin Red S staining and Ac-LDL uptake. pMSC differentiation in the presence of non-cytotoxic BP concentrations showed that nitrogen containing BPs had a significant inhibitory effect on cell migration and endothelial marker gene expression, as well as compromised endothelial differentiation as demonstrated using von Willebrand factor immunofluorescence staining and tube formation assay. This in vitro study demonstrated that at non-cytotoxic levels, nitrogen-containing BPs inhibit differentiation of pMSCs into cells of an endothelial lineage and affect the downstream functional capability of these cells supporting a multi-modal effect of BPs on angiogenesis as pathogenic mechanism contributing to bone healing disorders such as bisphosphonate related osteonecrosis of the jaws (BRONJ).