Chinese Journal of Dental Research, 02/2016

Objective: To propose new analytical tools that facilitate the obtention of quantifiable results for evaluating different dental care systems. Methods: The paper describes the construction of a composite indicator that measures dental health on a population basis in one overall indicator, the Dental Health Index (DHI). If the DHI is combined with a Dental Care Cost Index, an efficiency index (EI) can be created. Results: The use of these new instruments for analysing different dental care systems reveals that the Swedish and Danish populations enjoy the best dental health status, followed by US, Japanese, Australian and Canadian citizens. Germany ranks in the middle, while the Dutch and Finnish populations enjoy a lesser degree of dental health. Advanced dental health can be achieved in any oral healthcare system, irrespective of the underlying cost-sharing and funding structures. As a benchmark for industrialised countries, cost levels for dental care between 0.5% and 0.7% of GDP, seem to be the international norm. A population's dental status is determined by the degree to which preventive and tooth-preserving treatment approaches are practised, also amongst adults. Conclusion: The new instruments broaden the diagnostic possibilities for investigating different dental care systems. The greater the degree to which preventive and tooth-preserving treatment methods for the entire population are incorporated in daily clinical practice, the faster and better such systems progress and perform in terms of efficacy and efficiency. Keywords: benefit/cost analysis of the dental sector, overall dental health indicator, performance of dental care systems, efficiency of oral care

Objective: To investigate the effect of capsaicin cream on the secretion of the submandibular gland (SMG) and the parotid gland (PG) in the general population, with different chilli-eating habits. Methods: In two groups with different chilli-eating habits, the salivary flow rate of the SMG and the PG was detected at statics and different times, after application of capsaicin cream. Results: In both groups, the topical application of capsaicin cream could significantly increase the salivary secretion of SMG (P < 0.05), but the increase in the salivary flow rate of the SMG between the two groups had no significant difference (P > 0.05). On the other hand, although the salivary flow rate of PG also increased after stimulation, the increase had no statistical difference (P > 0.05). Conclusion: The application of capsaicin cream can effectively promote the secretion of the SMG and the PG, and its effect is independent of chilli-eating habits, which indicates that topical application of capsaicin cream can be considered as a potential treatment for the hypofunction of the salivary gland. Keywords: capsaicin, chilli, parotid gland, salivary secretion, submandibular gland, transient receptor potential vanilloid subtype 1, vanilloid receptor 1

Objective: To compare the influence of outer bow length difference and unilateral outer bow expansion on the 'asymmetric effect' of the headgear. Methods: Twelve 3D finite element models of a headgear with two tubes were designed, which were similar except for the outer bow length or the degree of unilateral expansion in Solid-Works 2011. A 3N force was applied to the outer bow ends in ANSYS Workbench 12.1 and the distalising, lateral forces to molars, moments and the energy of the system were evaluated. Results: As the degree of unilateral expansion increased, the net differences in all findings were increased up to a point, and then changed. There was an increasing pattern in the length difference group. Buccal movement was observed in the intact/shorter side molar. Conclusion: Unilateral shortened outer bow asymmetric headgears are more efficient and more predictable in clinical application than the unilateral outer bow expansion. Keywords: asymmetric cervical headgear, finite element method, unilateral expanded, unilateral shortened

Objective: To investigate the effect of osteoprotegerin (OPG) on the cementoblastic activity of a clonal population of immortalised murine cementoblasts (OCCM-30) in vitro. Methods: OCCM-30 cells were transiently transfected with the mouse OPG using the Avalanche transfection reagent. The ectopic expression of OPG was confirmed by enzyme-linked immunosorbent assay and quantitative polymerase chain reaction. The cell counting Kit-8 assay was used to investigate the effect of OPG on cell proliferation. The expression levels of cementoblastic-related mRNA and protein in the transfected OCCM-30 cells were detected using real-time PCR, Western blotting and immunohistochemical staining. Results: Satisfactory transfection efficiency was observed 48 h after transfection. The results of the cell proliferation assay indicated that the expansion rate of the OPG transfection group was greater than that of the control group at both 72 h and 96 h. The mRNA levels of osterix (Osx), protein kinase B (Akt1), cementum attachment protein (CAP) and osteopontin (Opn) were significantly upregulated (P < 0.05) in the OPG group. Protein levels of OPN, bone sialoprotein II (BSP II), osteocalcin (OC) and CAP, which are responsible for osteogenetic and cementoblastic activity, were significantly increased in the OPG-overexpressing group. Conclusion: Overexpression of OPG in OCCM-30 cells promotes cementoblastic activity. Keywords: cementoblastic, OCCM-30, osteoprotegerin (OPG), root repair, root resorption

Objective: To investigate the inhibition of Enterococcus faecalis by calcium peroxide (CaO₂). Methods: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Enterococcus faecalis by CaO₂ and calcium hydroxide (Ca(OH)₂) were determined by direct exposure tests (n = 10). The inhibition zone of E. faecalis mycoderm treated with CaO₂ and Ca(OH)₂ paste (53% w/w) was observed using agar diffusion tests (n = 20). The inhibition of E. faecalis biofilms by CaO₂/phosphate-buffered saline (PBS) and Ca(OH)₂/PBS suspensions were observed using confocal laser scanning microscopy and the percentages of live bacteria in the biofilms calculated. Results: The MIC of Ca(OH)₂ (4.5 to 5.5 mg/ml) was higher than the MIC of CaO₂ (2.0 to 2.5 mg/ml) (P < 0.05), and the MBC of Ca(OH)₂ (14.5 to 15.5 mg/ml) was higher than that of CaO₂ (3.0 to 3.5 mg/ml) (P < 0.05). No inhibition zone was observed for Ca(OH)₂ in agar diffusion tests, while the diameter of the inhibition zone around CaO₂ was 8.6 ± 0.4 mm. There were significant differences between groups in the percentages of surviving bacteria in E. faecalis biofilms after treatment (P < 0.05): group CaO₂ < group Ca(OH)₂ < group PBS < group BHI. Conclusion: The inhibition of E. faecalis by CaO₂ was greater than that by Ca(OH)₂. Keywords: biofilm, calcium hydroxide, calcium peroxide, Enterococcus faecalis

Pulpal necrosis of an immature permanent tooth with an open apex poses a challenge for the clinician. The conventional apexification technique using calcium hydroxide has yielded short-term success, but this technique has inevitable shortcomings. Hence, this case series aimed to evaluate the effectiveness of using bioceramics (iRoot BP) or mineral trioxide aggregate (MTA) for partial pulpotomies. Three boys aged 9 to 11 years old presented with partial pulp necrosis and symptomatic apical periodontitis of the mandibular right and left second premolar. The involved teeth were treated with a partial pulpotomy using either iRoot BP (case 1 and 2) or MTA (case 3). At the 8-month follow-up, no abnormal clinical signs or symptoms were observed. Periapical radiographs revealed a significant reduction in periapical radiolucency, a marked increase in the root canal wall thickness and ongoing closure of the apical opening. The bioceramic material (iRoot BP) and MTA both produced successful outcomes in the partial pulpotomy of immature teeth with partial pulp necrosis and apical periodontitis. However, iRoot BP was superior in terms of ease of clinical application, and would therefore be a better treatment alternative than MTA. Keywords: bioceramics, iRoot BP, mineral trioxide aggregate, partial pulpotomy