Catherine H.L. Hong

Nanoparticles strengthen intracellular tension and retard cellular migration.

Nanoparticles can have profound effects on cell biology. Here, we show that after TiO2, SiO2, and hydroxyapatite nanoparticles treatment, TR146 epithelial cell sheet displayed slower migration. Cells after exposure to the nanoparticles showed increased cell contractility with significantly impaired wound healing capability however without any apparent cytotoxicity. We showed the mechanism is through nanoparticle-mediated massive disruption of the intracellular microtubule assembly, thereby triggering a positive feedback that promoted stronger substrate adhesions thus leading to limited cell motility.

A systematic review of dental disease in patients undergoing cancer therapy

IntroductionThis purpose of this systematic review was to evaluate the literature and update our current understanding of the impact of present cancer therapies on the dental apparatus (teeth and periodontium) since the 1989 NIH Development Consensus Conference on the Oral Complications of Cancer Therapies.Review methodA systematic literature search was conducted with assistance from a research librarian in the databases MEDLINE/PubMed and EMBASE for articles published between 1 January 1990 and 31 December 2008. Each study was independently assessed by two reviewers. Taking into account predetermined quality measures, a weighted prevalence was calculated for the prevalence of dental caries, severe gingival disease, and dental infection. Data on DMFT/dmft, DMFS/dmfs, plaque, and gingival indexes were also gathered. The level of evidence, recommendation, and guideline (if possible) were given for published preventive and management strategies.ResultsSixty-four published papers between 1990 and 2008 were reviewed. The weighted overall prevalence of dental caries was 28.1%. The overall DMFT for patients who were post-antineoplastic therapy was 9.19 (SD, 7.98; n = 457). The overall plaque index for patients who were post-antineoplastic therapy was 1.38 (SD, 0.25; n = 189). The GI for patients who were post-chemotherapy was 1.02 (SD, 0.15; n = 162). The weighted prevalence of dental infections/abscess during chemotherapy was reported in three studies and was 5.8%.ConclusionsPatients who were post-radiotherapy had the highest DMFT. The use of fluoride products and chlorhexidine rinses are beneficial in patients who are post-radiotherapy. There continues to be lack of clinical studies on the extent and severity of dental disease that are associated with infectious complications during cancer therapy.

A systematic review of oral fungal infections in patients receiving cancer therapy

PurposeThe aims of this systematic review were to determine, in patients receiving cancer therapy, the prevalence of clinical oral fungal infection and fungal colonization, to determine the impact on quality of life and cost of care, and to review current management strategies for oral fungal infections.MethodsThirty-nine articles that met the inclusion/exclusion criteria were independently reviewed by two calibrated reviewers, each using a standard form. Information was extracted on a number of variables, including study design, study population, sample size, interventions, blinding, outcome measures, methods, results, and conclusions for each article. Areas of discrepancy between the two reviews were resolved by consensus. Studies were weighted as to the quality of the study design, and recommendations were based on the relative strength of each paper. Statistical analyses were performed to determine the weighted prevalence of clinical oral fungal infection and fungal colonization.ResultsFor all cancer treatments, the weighted prevalence of clinical oral fungal infection was found to be 7.5% pre-treatment, 39.1% during treatment, and 32.6% after the end of cancer therapy. Head and neck radiotherapy and chemotherapy were each independently associated with a significantly increased risk for oral fungal infection. For all cancer treatments, the prevalence of oral colonization with fungal organisms was 48.2% before treatment, 72.2% during treatment, and 70.1% after treatment. The prophylactic use of fluconazole during cancer therapy resulted in a prevalence of clinical fungal infection of 1.9%. No information specific to oral fungal infections was found on quality of life or cost of care.ConclusionsThere is an increased risk of clinically significant oral fungal infection during cancer therapy. Systemic antifungals are effective in the prevention of clinical oral fungal infection in patients receiving cancer therapy. Currently available topical antifungal agents are less efficacious, suggesting a need for better topical agents.

Nano-hydroxyapatite and Nano-titanium Dioxide Exhibit Different Subcellular Distribution and Apoptotic Profile in Human Oral Epithelium

Nanomaterials (NMs) such as titanium dioxide (nano-TiO2) and hydroxyapatite (nano-HA) are widely used in food, personal care, and many household products. Due to their extensive usage, the risk of human exposure is increased and may trigger NMs specific biological outcomes as the NMs interface with the cells. However, the interaction of nano-TiO2 and nano-HA with cells, their uptake and subcellular distribution, and the cytotoxic effects are poorly understood. Herein, we characterized and examined the cellular internalization, inflammatory response and cytotoxic effects of nano-TiO2 and nano-HA using TR146 human oral buccal epithelial cells as an in vitro model. We showed both types of NMs were able to bind to the cellular membrane and passage into the cells in a dose dependent manner. Strikingly, both types of NMs exhibited distinct subcellular distribution profile with nano-HA displaying a higher preference to accumulate near the cell membrane compared to nano-TiO2. Exposure to both types of NMs caused an elevated reactive oxygen species (ROS) level and expression of inflammatory transcripts with increasing NMs concentration. Although cells treated with nano-HA induces minimal apoptosis, nano-TiO2 treated samples displayed approximately 28% early apoptosis after 24 h of NMs exposure. We further showed that nano-TiO2 mediated cell death is independent of the classical p53-Bax apoptosis pathway. Our findings provided insights into the potential cellular fates of human oral epithelial cells as they interface with industrial grade nano-HA and nano-TiO2.

Review of postoperative bleeding risk in dental patients on antiplatelet therapy

OBJECTIVE We conducted a review of the literature to assess risk for oral bleeding complications after dental procedures in patients on antiplatelet therapy. STUDY DESIGN We conducted a search in Medline, Embase, and National Guideline Clearinghouse databases for studies involving patients on single and dual antiplatelet therapy that had invasive dental procedures or manipulations that induce oral bleeding. RESULTS The literature search yielded 15 studies that met inclusion criteria. There is a trend toward increased occurrence of immediate postoperative bleeding for dual antiplatelet therapy, but there is no increase in the occurrence of intra- or late postoperative bleeding complications. CONCLUSIONS We found no clinically significant increased risk of postoperative bleeding complications from invasive dental procedures in patients on either single or dual antiplatelet therapy. These findings support the recommendation that there is no indication to alter or stop these drugs, and that local hemostatic measures are sufficient to control bleeding.

Risk of postoperative bleeding after dental procedures in patients on warfarin: a retrospective study

OBJECTIVES The purpose of this retrospective study was to investigate the frequency of bleeding complications after invasive dental procedures in warfarinized patients and the possible risk factors. STUDY DESIGN The CoaguChek System was used to obtain an in-office international normalized ratio (INR) value for 122 patients (240 appointments), of which the mean age was 57.0 ± 15.9 years and 50% were males. Demographic and clinical information were obtained retrospectively from dental and medical records. RESULTS Five episodes (mean INR: 2.0 ± 0.8) of persistent bleeding were identified; 4 were after extractions and 1 was after implant placement. The frequency of bleeding was 4.8%, if only considering surgical procedures. Postoperative bleeding was significantly higher (P < .05) in patients who were taking anti-thrombotic medications in addition to warfarin. CONCLUSIONS There is a low incidence of persistent bleeding after invasive dental procedures in warfarinized patients but the risk appears to increase with the use of concomitant anti-thrombotic medications.

Frequency of Bleeding Following Invasive Dental Procedures in Patients on Low-Molecular-Weight Heparin Therapy

PURPOSE The purpose of this study was to determine the frequency of bleeding complications after invasive dental procedures in patients on low-molecular-weight heparin (LMWH) therapy. MATERIALS AND METHODS A chart review of patients who underwent invasive dental procedures while on LMWH therapy was conducted. The following information was obtained: demographics, medical history, social history, medications, relevant laboratory values, postoperative bleeding events, and use of local hemostatic agents and blood products. RESULTS Forty-one patients (21 men) were identified with 42 dental appointments. The mean age was 48 years (range, 16 to 78 years). Thirty-seven patients (90%) were on LMWH therapy for deep venous thrombosis prophylaxis. Thirty-one patients (76%) were on concomitant medications that may potentiate bleeding. Multiple dental extractions (range, 2 to 14 teeth) were performed during 19 dental appointments. Twenty-one appointments were for single-tooth extraction and 2 were for soft tissue biopsies. Three patients (7%) had postextraction bleeding events. All 3 patients were on LMWH (enoxaparin) and warfarin therapy concurrently. One patient had persistent bleeding after extraction of 4 teeth (international normalized ratio, 1.6), which was successfully controlled with topical thrombin, administration of vitamin K and fresh frozen plasma, and discontinuation of enoxaparin and warfarin. Postoperative bleeding in the other 2 patients was managed successfully with local hemostatic measures and home care instructions. CONCLUSION Our study suggests that, although postoperative bleeding in patients on LMWH therapy alone is rare to nonexistent, patients on warfarin and LMWH may be at increased risk of bleeding after invasive dental procedures.

Prevalence of molar incisor hypomineralization (MIH) in Singaporean children.

BACKGROUND There is a lack of data on molar incisor hypomineralization (MIH) in Asia, but this is not an indication that MIH is rare in the Asian population. Early identification of MIH is important as affected teeth frequently display post-eruptive enamel loss which would result in rapid caries progression. AIM This objective of this study was to assess the prevalence of MIH in Singaporean children. DESIGN Patients were recruited from 30 schools across Singapore. All children were examined by a single dentist, and the judgement criteria used were based on the 2003 European Academy of Paediatric Dentistry criteria. RESULTS A total of 1083 children; average age of 7.7 ± 0.3 years were examined. One hundred and thirty-five children (12.5%) had MIH. A significantly higher proportion of children of the Malay ethnicity had MIH, compared to Chinese children (P = 0.02). Post-eruptive enamel breakdown and the presence of atypical restorations were correlated with increasing number of MIH teeth/child (Rho= 0.599, P < 0.001) and the cumulative enamel opacity colour score (Rho = 0.601, P < 0.001). CONCLUSIONS Our findings suggest the role of ethnicity in MIH occurrence and that MIH severity may be influenced by the number of MIH teeth/child and the cumulative enamel opacity colour score.

Selective serotonin reuptake inhibitors and oral bleeding complications after invasive dental treatment.

OBJECTIVE The purpose of this study was to examine the frequency of oral bleeding complications after invasive dental procedures in patients taking selective serotonin reuptake inhibitor (SSRI) medications. STUDY DESIGN In this retrospective cohort study, we included dental patients who had invasive dental treatment and were taking an SSRI medication. Data collected included demographics, medical history, dental visits and procedures, and use of adjunctive measures to control bleeding. Primary outcomes included documentation of return visits or phone calls to the dental clinic or emergency department (ED) for oral bleeding, and oral bleeding or use of blood products for inpatients. RESULTS There were 92 patients taking SSRIs who had 145 invasive procedure visits, consisting of extractions, implant surgery, alveoloplasty, periodontal surgery, subgingival scaling and root planning, and biopsy. There were 110 extraction visits yielding a total of 167 extractions. Among all patients, there was 1 return visit to the clinic and 1 telephone call with a chief complaint of oral bleeding. CONCLUSIONS The frequency of oral bleeding complications after invasive dental treatment is low to negligible in patients on SSRI medications.

World Workshop on Oral Medicine VI: an international validation study of clinical competencies for advanced training in oral medicine.

OBJECTIVE To explore international consensus for the validation of clinical competencies for advanced training in Oral Medicine. STUDY DESIGN An electronic survey of clinical competencies was designed. The survey was sent to and completed by identified international stakeholders during a 10-week period. To be validated, an individual competency had to achieve 90% or greater consensus to keep it in its current format. RESULTS Stakeholders from 31 countries responded. High consensus agreement was achieved with 93 of 101 (92%) competencies exceeding the benchmark for agreement. Only 8 warranted further attention and were reviewed by a focus group. No additional competencies were suggested. CONCLUSION This is the first international validated study of clinical competencies for advanced training in Oral Medicine. These validated clinical competencies could provide a model for countries developing an advanced training curriculum for Oral Medicine and also inform review of existing curricula.