DENTISTRY

Background: First, first permanent molars (FPMs) of poor prognosis are often planned for extraction at an 'ideal time' so that second permanent molars (SPMs) erupt favourably to replace them. However for lower FPM extractions, timing is not an accurate predictor of success. Objective: The aim of this study was to identify additional radiographic factors that could better predict the degree of spontaneous space closure of the lower SPM following FPM extraction. Methods: Data from a previous study of 127 lower SPMs from 66 patients was re-analysed by incorporating additional radiographic factors. These included calcification stage of the bifurcation of the SPM, position of the second premolar, mesial angulation of SPM in relation to the FPM, and presence of the third permanent molar. Results were analysed using ordered logistic regression. Results: Only 58 per cent of FPMs extracted at the 'ideal time' (SPM development at Demirjian stage E) had complete space closure. The best outcomes resulted from a combination of SPMs not at Demirjian development stage G, together with the presence of mesial angulation of the SPM and presence of the third permanent molar, where 85 per cent of those cases had complete space closure. Conclusions: Apart from extraction timing of the FPM, consideration must also be given to the presence of the third permanent molar and angulation of the SPM in order to ensure a reliable degree of spontaneous space closure of the lower SPM.

Aims: To investigate the incidence and reasons for tooth loss during active periodontal therapy (APT) and periodontal maintenance (PM) in a specialist institution. Material and methods: Retrospective data were collected from 273 patients [all compliers (AC)] and cross-sectional data from 39 patients after discontinuation of PM [non-compliers (NC)] for at least 7 years after APT. Descriptive statistics and regression analysis were performed. A comparison was made between AC and NC. The prognostic factors associated with tooth loss during PM were identified. Results: AC lost 1.3 teeth/patient during APT and 0.9 teeth/patient during PM (mean 10.7 years). Tooth loss due to periodontitis was 0.03 teeth/patient/year. The age of X60 was a significant predictor of tooth loss during PM (odds ratio of 2.1). NC lost 1.1 teeth/patient during APT and 2.7 teeth/patient during discontinuation (mean 9.6 years). Tooth loss due to periodontitis was 0.22 teeth/patient/year, a sevenfold increase (po0.05) compared with AC. Regression analysis failed to identify any significant predictors for tooth loss during the discontinuation of PM. Conclusions: In this study, the provision of PM led to minimal tooth loss, especially due to periodontitis, for a mean period of 10 years after APT. The completion of APT without PM may predispose patients to lose more teeth compared with patients who undergo PM.

This paper addresses the problem of adverse pregnancy outcome in relation to periodontal disease. There is compelling evidence that a link exists between pre-term low birth weight (PLBW) and periodontitis. Although 25% to 50% of PLBW deliveries occur without any known aetiology, there is increasing evidence that infection may play a significant role in pre-term delivery. A model explaining the plausible relationship is proposed based upon the concept of infection leading to a cascade of inflammatory reactions associated with pre-term labour and periodontal disease. Current evidence has pointed to an interest in dental intervention studies to control periodontal disease as one of the potential strategies to reduce pre-term labour. This paper reviews the potential association between periodontal infection and adverse pregnancy outcomes.

Optimisation of plaque control is essential for the success of non-surgical and surgical periodontal therapy. This cannot be achieved with brushing alone; hence, there is a need for adjunctive interdental cleaning aids. The aim of this paper is to provide an overview of different interdental cleaning aids and review the literature for consensus on their effectiveness. A literature search of articles in English, up to December 2018, was conducted in Pubmed. High-quality flossing is difficult to achieve, and ineffective routine use of floss may not confer significant benefits over brushing alone. Interdental brushes are more effective than brushing as a monotherapy. They are at least as good if not superior to floss in reducing plaque and gingivitis. Although they are effective for patients regardless of their periodontal status (healthy or active), they are especially indicated in periodontal patients where widened embrasures are common. Added benefits include ease of use, patient ac...

Background: Dental trauma in children and adolescents represent one of the major public health problems worldwide. School is one of the locations with greatest prevalence of traumatic dental injuries. So, awareness of school teachers about emergency management of dental trauma is an important concept for long term maintenance of oral health and to prevent its future consequences. Aim: This study was conducted to examine the effect of educational intervention on school teachers' awareness about emergency management of dental trauma in school children.

Diabetes and periodontitis are common chronic diseases in the world, and abundant epidemiological evidence implies a bidirectional relationship between the two diseases. It appears that diabetes is a risk factor for greater periodontal destruction, whereas managing periodontitis can also contribute to better glycemic control. The underlying regulatory mechanisms are also bidirectional. The hyperglycemic status may directly alter subgingival microbial compositions, impair cellular function, and change collagen metabolism. The formation of advanced glycation end-products (AGEs) can further modify the extracellular matrix, and establishment of cellular receptor binding can amplify inflammation. Moreover, periodontitis also induces hyperlipidemia and insulin resistance. This cyclical relationship converges via overproduction of proinflammatory cytokines, such as tumor necrosis factor-a and interleukin-1b. Thus, this article highlights the importance of maintaining periodontal health to eliminate systemic complications and meticulous metabolic control to prevent further periodontal destruction. From a systemic aspect, targeting proinflammatory cytokines or receptors of AGEs could be a potential modality for treating periodontitis.

Objectives: This narrative review aims to outline the concepts on the significance of the width of attached gingiva around teeth and implants to enable the clinician to decide on the need for gingival augmentation in different clinical scenarios. Data and sources: An electronic search was done on PUBMED & Cochrane Database using the keywords from 1972 to November 2009. A manual hand search was also done in Journal of Periodontology and Journals of Clinical Periodontology for relevant articles under this topic. Any relevant paper from the references was hand searched. A total of 1167 references were obtained, 103 full text papers was retrieved of which 59 articles was selected for this review. Conclusions: The width of attached gingiva is not significant to maintain periodontal health in the presence of adequate oral hygiene. However, thin gingival tissues around teeth with restorations or undergoing labial orthodontic tooth movement may be more susceptible to recession. The functional need for attached gingiva around implants has not been established but its aesthetic value has been widely accepted.

Objectives: Timely augmentation of the physiological events of dentoalveolar repair is a prerequisite for the optimization of the outcome of regeneration. This study aimed to develop a treatment strategy to promote dentoalveolar regeneration by the combined delivery of the early mitogenic factor platelet-derived growth factor (PDGF) and the late osteogenic differentiation factor simvastatin. Materials and Methods: By using the coaxial electrohydrodynamic atomization technique, PDGF and simvastatin were encapsulated in a double-walled poly(d,l-lactide) and poly(d,l-lactide-co-glycolide) (PDLLA-PLGA) microspheres in five different modes: microspheres encapsulating bovine serum albumin (BB), PDGF alone (XP), simvastatin alone (SB), PDGF-in-core and simvastatin-in-shell (PS), and simvastatin-in-core and PDGF-in-shell (SP). The microspheres were characterized using scanning electronic microscopy, and the in vitro release profile was evaluated. Microspheres were delivered to fill large osteotomy sites on rat maxillae for 14 and 28 days, and the outcome of regeneration was evaluated by microcomputed tomography and histological assessments. Results: Uniform 20-mm controlled release microspheres were successfully fabricated. Parallel PDGF-simvastatin release was noted in the PS group, and the fast release of PDGF followed by the slow release of simvastatin was noted in the SP group. The promotion of osteogenesis was observed in XP, PS, and SP groups at day 14, whereas the SP group demonstrated the greatest bone fill, trabecular numbers, and thickest trabeculae. Bone bridging was evident in the PS and SP group, with significantly increased osteoblasts in the SP group, and osteoclastic cell recruitment was promoted in all bioactive molecule-treated groups. At day 28, osteogenesis was promoted in all bioactive moleculetreated groups. Initial corticalization was noted in the XP, PS, and SP groups. Osteoblasts appeared to be decreased in all groups, and significantly, a greater osteoclastic cell recruitment was noted in the SB and SP groups. Conclusions: Both PDGF and simvastatin facilitate dentoalveolar regeneration, and sequential PDGF-simvastatin release (SP group) further accelerated the regeneration process through the enhancement of osteoblastogenesis and the promotion of bone maturation.

The study aims to compare the effects of adjunctive photodynamic therapy (PDT) with scaling and root debridement alone on periodontal parameters and inflammatory cytokines in residual pockets of patients undergoing maintenance therapy. 27 subjects, each with at least 2 residual pockets ≥5mm, were recruited for this randomized, split-mouth controlled trial, providing total of 72 sites. Probing pocket depth (PPD), recession, clinical attachment loss (CAL), plaque and bleeding on probing of all sites were examined at baseline, 3 and 6 months. Gingival crevicular fluids (GCFs) were collected to determine levels of IL-1β, IL-6, IL-8, TNF-α and MMP-8 via enzyme-linked immunosorbent assay. At baseline, all sites received subgingival instrumentation and polishing. In addition, test sites received a single application of PDT using Fotosan® with toluidine blue O solution photosensitizer. At 3 and 6 months, site level analysis was performed for changes in clinical parameters and cytokine level...

Withincreasingknowledgeofwoundbiologyandmaterialsciences,theprovisionof dentalimplantsasatreatmentmodalityhasbecomeincreasinglypredictableandmore commonly used to replace missing teeth. However, without appropriate follow up, peri-implant diseases could develop and affect the long-term success of implants. Currently, there is not enough focus on the prevention of peri-implant diseases, as comparedtothedefinitionofthedisease,itsprevalence,andtreatment.Inthepresent study,weaimtosummarizevariousfactorsinfluencingthesuccessfulmaintenanceof dentalimplantsandhighlightcurrentgapsinknowledge.Factorsinfluencingthesuccessfulmaintenanceofdentalimplantscanbedividedintothreecategories:implant-, dentist-, and patient-related factors. Patients with dental implants are often more dentally aware, and this offers an advantage. Compared to gingiva, peri-implant mucosarespondsatadifferentpacetothebacterialchallenge.Dentalpractitioners shouldbeawareofhowtreatmentprotocolsaffectlong-termsuccess,andbevigilant indetectingperi-implantdiseasesatanearlystage.Comparedtoperiodontalmaintenance,lesslongitudinalstudiesonimplantmaintenanceareavailable,andtherefore, thereisatendencytorelyheavilyoninformationextrapolatedfromtheperiodontal literature.Morestudiesonthesignificanceofimplantmaintenancecarearerequired.

To study the perceived sources of stressful events in dental students and the relationships between their self-perceived stress levels and salivary IgA. Undergraduates as well as postgraduates at the Faculty of Dentistry, National University of Singapore were surveyed one month after the new term. A 38-item dental environmental stress (DES) questionnaire, with subscales of academic work (AW), clinical factors (CF), faculty and administration factors (FA) and personal factors (PF), was used to identify the potential stressors in the dental environment. A 4-point perceived stress scale was used to rank their self-perceived stress levels. Enzyme linked immunosorbent assay method was used to determine the salivary IgA level. One hundred and thirty students (81.3% - valid response rate) participated in the study. Overall, students ranked AW with the highest score (mean 2.76), followed by CF (2.67), FA (2.24) and PF (2.16). Among the 38 items of DES questionnaire, 1st year students percei...

Mesenchymal stem cells (MSCs) are potential therapeutics for the treatment of periodontal defects. It is increasingly accepted that MSCs mediate tissue repair through secretion of trophic factors, particularly exosomes. Here, we investigated the therapeutic effects of human MSC exosome-loaded collagen sponge for regeneration of surgically created periodontal intrabony defects in an immunocompetent rat model. We observed that relative to control rats, exosome-treated rats repaired the defects more efficiently with regeneration of periodontal tissues including newly-formed bone and periodontal ligament (PDL). We also observed that concomitant with this, there was increased cellular infiltration and proliferation. We therefore postulated that MSC exosomes enhanced regeneration through increased cellular mobilisation and proliferation. Using PDL cell cultures, we demonstrated that MSC exosomes could increase PDL cell migration and proliferation through CD73-mediated adenosine receptor activation of pro-survival AKT and ERK signalling. Inhibition of AKT or ERK phosphorylation suppressed PDL cell migration and proliferation. Our findings demonstrated for the first time that MSC exosomes enhance periodontal regeneration possibly by increasing PDL migration and proliferation. This study suggests that MSC exosome is a viable ready-to-use and cell-free MSC therapeutic for the treatment of periodontal defects. Statement of significance Mesenchymal stem cell (MSC) therapies have demonstrated regenerative potential for the treatment of periodontal defects. However, translation of cellular therapies is hampered by challenges in maintaining optimal cell vitality and viability from manufacturing and storage to final delivery to patients. Although the use of MSCs for tissue repair was first predicated on their differentiation potential, the therapeutic efficacy of MSCs has increasingly been attributed to its paracrine secretion, particularly exosomes or small extracellular vesicles. In this study, MSC exosome-loaded collagen sponge enhanced periodontal regeneration in an immunocompetent rat periodontal defect model without any obvious adverse effects. These findings provide the basis for future development of MSC exosomes as a cell-free strategy for periodontal regeneration.

This study aims to assess the difference in self-perceived stress before and after an academic assessment and its association with the marks scored and to study the association of salivary cortisol, Immunoglobulin A (IgA), and chromogranin A (CgA) with stress levels before and after the assessment. Thirty-one third-year dental undergraduates indicated how stressed they felt on a 5-point rating scale just prior to and immediately after a one-hour written test. Five-minute unstimulated whole saliva samples were also collected at those times to measure salivary cortisol, IgA, and CgA. Students rated significantly higher stress scores before (median [inter quartile range]: 3[1]), compared to after the test (2[2]) (p=0.015). Higher cortisol levels (mean: 6.32 nmol/l) were observed before than after the exam (mean: 5.16 nmol/l) (p=0.015). No significant differences were noted between the pre-and post-test saliva samples for salivary IgA and CgA levels. A negative correlation was seen between post-test stress scores and test marks (Spearman's r =-0.325, p=0.07). Dental students perceived a higher level of stress prior to the test, which declined after that. Pre-test stress scores were associated with raised salivary cortisol, but not IgA or CgA. Students who perceived higher levels of stress after the test generally had poorer results.

Resveratrol (RES) is a natural polyphenol with potential as an adjunctive therapeutic modality for periodontitis. However, its inferior pharmacokinetics and toxicity concerns about its commonly used solvent dimethyl sulfoxide (DMSO) hinder translation to clinical applicability. Our study aimed to investigate the comparative antimicrobial properties of RES and its analogues (pterostilbene [PTS], oxyresveratrol [OXY] and piceatannol [PIC]), utilizing 2-hydroxypropyl-β-cyclodextrin (HPβCD) as a solubiliser, which has a well-documented safety profile and FDA approval. These properties were investigated against Fusobacterium nucleatum, a key periodontal pathogen. PTS demonstrated the most potent antibacterial effects in HPβCD, with MIC > 60-fold lower than that of RES, OXY and PIC. In addition, PTS inhibited F. nucleatum biofilm formation. PTS exerted antimicrobial effects by eliciting leakage of cellular contents, leading to loss of bacterial cell viability. PTS also conferred immuno...

Objectives: To investigate the effect of defined versus undefined periodontal maintenance after implant therapy on the prevalence of peri-implant complications. Material and Methods: Two hundred patients who underwent dental implant therapy in the National Dental Centre Singapore (NDCS) from 2005 to 2012 were recruited. One hundred patients had regular periodontal maintenance (defined maintenance programme group, DMP) and the other 100 patients had no documentation of periodontal maintenance (undefined maintenance programme group, UMP). Full mouth bleeding scores (FMBS), periodontal probing depths (PPD) and peri-implant probing depths (PiPD) were evaluated within 6 months of prostheses delivery (T 0) and at re-examination (T 1). Peri-implant bone level changes were analyzed radiographically. Results: The mean follow-up time was 6.8 years. Five out of 289 implants were lost (cumulative survival rate = 98.3%). 6.0% of DMP patients and 20.0% of UMP patients had peri-implantitis (p = 0.003). Peri-implantitis was defined as bleeding on probing, increase in peri-implant probing depth and peri-implant bone loss ≥ 0.5mm. At the implant level, 4.0% of the DMP group implants and 17.2% of the UMP group implants were diagnosed with peri-implantitis (p = 0.0003). One implant in the DMP group and 13 implants in the UMP group had bone loss ≥ 2mm (p<0.0001). Multivariate regression showed that absence of regular maintenance (OR=0.24, p=0.003) was significantly associated with peri-implantitis.

195 Hong Kong Chinese employees from a single company participated in a 10-month longitudinal study on the effects of various modes of delivery of oral hygiene messages on their gingivai health. Subjects were aiiocated to one of the following modes of oral hygiene education: (i) personai instruction; (2) seifeducation manuai; (3) video; (4) a combination of 2 or more of these modes of instruction. Scaling or any other form of periodontai treatment was not given throughout the study period. Full mouth chnical examinations were carried out using a Williams Periodontal probe to examine for the presence or absence of plaque and bleeding on probing from the gingivai sulcus. At 2 weeks, 4 months and 10 months, results showed significant reductions in the mean % of plaque and bleeding when compared with baseline. No significant differences were found between the groups given the various modes of oral hygiene education. The study does confirm the effectiveness of oral hygiene alone in improving gingivai heaith, but the lack of difference in the outcome of various oral hygiene education approaches indicates that the mode of instruction is not crucially important to the end result. However, it has to be acknowledged that improvement in oral hygiene may be related to factors other than the oral hygiene programme itself. The findings have significant impiications in oral heaith promotion programmes to improve the periodontai status of the iocal community.