Objective: Inflammation is one of the most common complications observed when using orthodontic miniscrews. Chlorhexidine mouthwash can beused to prevent and reduce the degree of inflammation, but long-term use of this solution may lead to some side effects. This study sought to evaluatethe peri-miniscrew antibacterial effect of 1% chitosan, a biomaterial with antibacterial properties, relative to 0.2% chlorhexidine mouthwash.Methods: A randomized, double-blind clinical trial was conducted at the Dental Teaching Hospital and Oral Biology Research Laboratory at theUniversity of Indonesia from February to June 2019. Thirty subjects (25 females and five males) were randomly assigned to rinse with 1% chitosan(n=10), 0.2% chlorhexidine digluconate (n=10), and Aquadest (n=10) in addition to their usual oral hygiene procedure for 4 days. Peri-miniscrewclinical inflammation signs were recorded and peri-miniscrew plaque collected before and after 4 days of rinsing. The total bacterial and red-complexbacteria count in plaque samples were evaluated by a real-time polymerase chain reaction.Results: Chitosan and chlorhexidine showed antibacterial activity, reducing total bacterial count around orthodontic miniscrews (p<0.05). Theantibacterial activity of chitosan on total bacteria was not significantly different from that of chlorhexidine (p≥0.05). Regarding the antibacterialactivity of chitosan on red-complex bacteria, the best result seen was a 58% bacteria count reduction in Tannerella denticola.Conclusion: Chitosan has potential antibacterial activity and could be used in mouthwash to maintain peri-miniscrew hygiene.

Background: Due to advances in digital technology, it is possible to obtain digital dental models through intraoral scanning. The stereolithographic data collected from the scanner can subsequently be printed into a three-dimensional dental model in resinic material. However, the accuracy between digital dental models and printed dental models needs to be evaluated since it might affect diagnosis and treatment planning in orthodontic treatment. This study aimed to evaluate the accuracy of digital models scanned by a Trios intraoral scanner and three-dimensional dental models printed using a Formlabs 2 3D printer in linear measurements and Bolton analysis. Methods: A total of 35 subjects were included in this study. All subjects were scanned using a Trios intraoral scanner to obtain digital study models. Stereolithographic data from previous scanning was printed using a Formlabs 2 3D printer to obtain printed study models. Mesiodistal, intercanine, intermolar, and Bolton analysis from all types of study models were measured. The intraclass correlation coefficient was used to assess intraobserver and interobserver reliability. All data were then statistically analyzed. Results: The reliability tests were high for both intraobserver and interobserver reliability, which demonstrates high reproducibility for all measurements on all model types. Most of the data compared between study models showed no statistically significant differences, though some data differed significantly. However, the differences are considered clinically insignificant. Conclusion: Digital dental models and three-dimensional printed dental models may be used interchangeably with plaster dental models for diagnostic and treatment planning purposes. Keywords: Accuracy, 3D printing, digital dental model, printed dental model.

CONTEXT: Orthodontic miniscrew implants (OMIs) are widely used as anchorage alternatives, but recent studies revealed the corrosion behavior of OMIs when they come in contact with mouthwashes. The corrosion materials that are released can cause toxicity, allergy, and mutagenicity. AIMS: This study aims to analyze the cytotoxicity effects of OMIs exposed to different types of mouthwash using human gingival fibroblast (HGFs). SETTINGS AND DESIGN: Experimental laboratory research. METHODS AND MATERIAL: Twenty-eight samples of Ti alloy OMIs immersed separately in four groups of different types of mouthwash (chlorhexidine gluconate 0.2% mouthwash (CHX), fluoridated (sodium fluoride 0.2%) mouthwash, chitosan mouthwash 1.5%, and aquadest) for 28 d. Elution of each group and the mouthwash itself were added to the cell culture and incubated for 24 h. Changes in cell viability were performed by MTT Assay. STATISTICAL ANALYSIS USED: Data were tested for normality with Shapiro–Wilk, homogeneity with Levene test, and analyzed using an independent T-test ( P < 0.05). RESULTS: The differences between the cytotoxicity of the elution of MIO and the mouthwash solution itself in the group of CHX and Fluoride were statistically significant ( P < 0.05). No significant differences were found in the group of chitosan and aquadest ( P > 0.05). CONCLUSIONS: The 1.5% chitosan mouthwash can be offered to patients with Ti alloy-based OMIs rather than the 0.2% chlorhexidine gluconate and 0.2% sodium fluoride mouthwashes.

Objective: The objective of this study was to develop an antibacterial flowable composite containing silver nanoparticle (AgNP) for the prevention ofperiodontal disease in fixed retainers.Methods: About 1% AgNP was incorporated into a commercial composite (tetric flow). The experimental and control products were used to bondfixed retainers to 28 extracted mandibular first premolars. The samples were randomly divided into four groups (n=7): Premolar bonded withfiber-reinforced composites and tetric flow (F1); premolar bonded with fiber-reinforced composites and AgNP-enhanced tetric flow (F2); premolarbonded with multistranded wires (MW) and tetric flow (M1); and premolar bonded with MW and AgNP-enhanced tetric flow (M2). Each sample wassubmerged in a test tube containing bacterial Treponema denticola solution and was incubated for 24 h and 37°temperature. The bacterial colony ineach group was counted and analyzed.Results: This study showed that there was significant difference of T. denticola colony count between groups with and without AgNP-enhancedcomposites in both types of retainers.Conclusion: AgNP-enhanced flowable composites reduce the bacteria T. denticola colony count and possibly inhibit periodontal disease.

Objective: To evaluate the differences in the stress distribution on the upper first molar with and without transpalatal arch and a second molar when a 150 g force is applied during canine distalization using finite element analysis. Material and Methods: We constructed several models with data obtained by scanning human skulls using cone beam computed tomography. A robust three-dimensional maxillary model was then constructed by assembling the previously completed robust models of the maxilla and second molar with and without transpalatal arch, and canine distalization was simulated using a 150 g force. The data consisted of color spectrum figures representing the stress distribution. Results: For the upper first molar and its alveolar bone, there was a statistically significant difference in the stress distribution between the upper first molar with transpalatal arch, the upper first molar without transpalatal arch, and the upper first molar with transpalatal arch and a second molar as reinforcement. Conclusion: Stress distribution on the first molar and alveolar bone, indicated by the maximum and minimum principal stress, as well as the pressure von Mises, exhibited a similar pattern. The highest amount of stress was observed in the model of the first molar without transpalatal arch, followed by the model of the first molar with transpalatal arch and, finally, the model of the first molar with transpalatal arch and a second molar.