Bone remodelling marker expression in grafted and ungrafted sheep tooth extraction sockets: A comparative randomised study.

OBJECTIVE: To compare key markers of bone remodelling in a sheep tooth extraction model for sockets left to heal naturally or grafted with the bovine-derived xenograft Bio-Oss® covered with a collagen Bio-Gide® membrane. DESIGN: Right side premolar teeth were removed from thirty Romney-cross ewes. Standardised sockets in each sheep were randomly allocated treatments, a grafted test and an empty control. At 4-, 8- and 16-weeks sheep were euthanized and tissue collected (N = 10/group). RANK, RANKL and OPG immunohistochemical analysis was performed (n = 3). RANK, RANKL, OPG, COL1A1, TIMP3, SP7 and MSX2 mRNA expression levels were determined using RT2-qPCR assays (n = 3). RESULTS: Histologically, more new woven bone was observed in the test group at all time points. Strong RANK and RANKL expression was found in both groups; at all time points with stronger RANK staining in the test group at 8 and 16 weeks. Strong OPG staining was localized to both osteoblasts and connective tissues. RANK receptor mRNA was expressed at a lower level in the test group (-4.26-fold; p = 0.02) at 4 weeks and SP7 at 16 weeks (-2.89-fold; p = 0.04). COL1A1 and TIMP3 mRNA expression increased significantly over time in the control group (p = 0.045, F = 5.4 and p = 0.003, F = 42.2 respectively). CONCLUSION: Socket healing over time was comparable. The sheep tooth extraction model was found to be suitable for the evaluation of changes in the alveolar bone at the molecular level.

Migration of oral health professionals: a scoping review protocol.

INTRODUCTION: Each year, many dental professionals are trained; however, many low-income and middle-income countries face a scarcity of dental professionals. This trend has been observed because of the migration of oral health professionals from developing to developed countries for various reasons such as professional, economic or personal. This negatively impacts the healthcare system by causing critical shortages of trained personnel to support the oral healthcare needs of the countries where the oral health professionals migrate from (source countries). The key objectives of this scoping review are to assess the intentions behind the migrations, identify the countries the graduates migrate to and from, examine the barriers to and facilitators of integrating oral health professionals, as well as the challenges they face post migration. METHODS AND ANALYSIS: A scoping review will be reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Review (PRISMA-ScR) and the Joanna Briggs Institute guidelines. Scientific databases such as Dentistry and Oral Sciences Source, Cumulative Index to Nursing and Allied Health Literature, MEDLINE and Scopus will be systematically searched to identify potential articles. In addition, grey literature will be searched to identify unpublished materials relevant to the topic using Google Scholar and Google. The reviewers will assess the retrieved sources in a three-step search strategy, and a PRISMA-ScR flowchart will document the numbers of identified, screened and excluded sources. The scoping review will collate and present the findings as a descriptive analysis. Finally, the narrative descriptions will be presented in a thematic form based on the findings of the scoping review. ETHICS AND DISSEMINATION: This scoping review is based on a secondary analysis of published data; hence, ethical approval is not required. The findings of this study will be disseminated through publication in a peer-reviewed journal, professional networks and conferences.

Expression of the pleiotrophin-midkine axis in a sheep tooth socket model of bone healing.

OBJECTIVE AND BACKGROUND: Resorption of alveolar bone after tooth extraction is a common problem often requiring bone grafting. The success of the grafting procedures is dependent on multiple factors including the presence of growth factors. This is the first in vivo study to investigate the role of the pleiotrophin family of cytokines in alveolar bone regeneration. This research investigated the role of the pleiotrophin-midkine (PTN-MDK) axis during osteogenesis, with and without a grafting material, after tooth extraction in a sheep model. METHODS: Thirty Romney-cross ewes were anesthetized, and all premolar teeth on the right side were extracted. The sockets were randomized to controls sites with no treatment and test sites with Bio-Oss® graft material and Bio-Gide® membrane. Samples were harvested after sacrificing animals 4, 8, and 16 weeks post-grafting (n = 10 per time-point). Tissue for qRT2 -PCR gene analysis was recovered from the socket next to the first molar using a trephine (Ø = 2 mm). Each socket was fixed, decalcified, paraffin-embedded, and sectioned. Immunohistochemistry was conducted to localize both PTN and MDK along with their receptors, protein tyrosine phosphatase receptor type Z1 (PTPRZ1), ALK receptor tyrosine kinase (ALK), and notch receptor 2 (NOTCH2). RESULTS: Within the healing sockets, high expression of genes for PTN, MDK, NOTCH2, and ALK was found at all time-points and in both grafted and non-grafted sites, while PTPRZ1 was only expressed at low levels. The relative gene expression of the PTN family of cytokines was not statistically different at the three time-points between test and control groups (p > .05). Immunohistochemistry found PTN and MDK in association with new bone, NOTCH2 in the connective tissue, and PTPRZ1 and ALK in association with cuboidal osteoblasts involved in bone formation. CONCLUSIONS: The PTN-MDK axis was highly expressed in both non-grafted and grafted sockets during osteogenesis in a sheep model of alveolar bone regeneration with no evidence that grafting significantly affected expression. The activation of NOTCH2 and PTPRZ1 receptors may be important during bone regeneration in vivo. The discovery of the PTN-MDK axis as important during alveolar bone regeneration is novel and opens up new avenues of research into these stably expressed highly active cytokines. Growth factor supplementation with PTN and/or MDK during healing may be an approach for enhanced regeneration or to initiate healing where delayed.

Psychometric properties of the Child-OIDP and oral health-related quality of life (OHRQoL) in secondary schools in Suva, Fiji.

BACKGROUND: Oral health-related problems are highly prevalent and, like many other diseases, affect Quality of Life. Although most primary schools in Fiji have supervised school brushing programs and have regular screenings these preventive aspects are missing in secondary schools. OBJECTIVE: To assess the internal consistency reliability, face and content validity of the Child-OIDP questionnaire and determine the oral health-related quality of life in 15-year-olds in Suva, Fiji. METHODS: A cross-sectional prospective study was carried out on 15-year-old children from four secondary schools in Suva, Fiji from 2014 to 2015. All students enrolled in the 10th and 11th year of studies were included. Multi-stage cluster sampling was used to identify the participants and the sample size of 367 was calculated. The Child Oral Impact on Daily Performance (Child-OIDP) self-administered questionnaire was used to collect data and data was analyzed using Epi-Info (3.5.1). RESULTS: A total of 281 students (76.6%) responded, of whom 47.0% experienced at least one impact. Cronbach's alpha for the Child-OIDP frequency items was 0.70 and the corrected item-total correlation ranged from 0.13 to 0.57. The most common performances that were affected were eating (27.8%) and relaxing (12.8%). Performances that were severely and most severely influenced were social contact (23.1%), smiling (16.7%) and relaxing (16.7%). The most common conditions leading to impacts were dental sensitivity (38.4%), dental caries (23.5%) and toothache (21.4%). CONCLUSION: The original version of the Child-OIDP is a reliable index with acceptable internal consistency when used directly in the Fiji setting, however, further studies to validate the tool will be useful. Oral impacts were prevalent, but not severe.

Fluoride concentration in drinking water samples in Fiji.

OBJECTIVE: The main aim of this study was to determine the content of fluoride in drinking water from sources within the sampling areas for the National Oral Health Survey (NOHS) 2011 from the Central, Northern, Western and Eastern Divisions in the Fiji Islands. METHOD: Drinking water samples were collected from taps, a waterfall, wells, creeks, streams, springs, rivers, boreholes and rain water tanks in a diverse range of rural and urban areas across the Fiji Islands. A total of 223 areas were sampled between December 2014 and June 2015. Samples were analysed for fluoride using a colorimetric assay with the Zirconyl-SPADNS Reagent. The samples were pre-treated with sodium arsenite solution prior to analysis to eliminate interference from chlorine. RESULTS: Measured fluoride concentrations ranged from 0.01 to 0.35 ppm, with a mean concentration across all samples of 0.03 + 0.04 ppm. No samples achieved the optimal level for caries prevention (0.7 ppm). The Western Division had the highest fluoride levels compared to the other Divisions. The highest single fluoride concentration was found in Valase. The drinking water for this rural area located in the Western Division is from a borehole. The lowest concentrations of fluoride were in reticulated water samples from rural areas in the Central Division, which were consistently less than those recorded in the Northern, Eastern and Western Divisions. CONCLUSION: All samples had fluoride concentrations below the optimum level required to prevent dental caries. Implications for public health: This research forms part of the objectives of the 2011 National Oral Health Survey in Fiji. At present, Fiji lacks water fluoridation and therefore a baseline of the fluoride content in drinking water supplies is essential before water fluoridation is implemented. The results from this study would be beneficial in designing caries-preventive strategies through water fluoridation and for comparing those strategies with caries prevalence overtime.