The gamification and development of a chatbot to promote oral self-care by adopting behavior change wheel for Taiwanese children.

Background: Oral health is closely related to general health and quality of life. School-aged children are at a critical stage for developing their self-care ability in oral health. Digital interventions can encourage and facilitate oral self-care in children. Objective: This study aims to present the development of an educational chatbot for school-aged children to address their oral self-care and evaluate its usability. Methods: The development and evaluation of the chatbot for oral self-care consisted of four stages: target behavior analysis, intervention design, system development, and the chatbot evaluation. The target behavior analysis identified barriers to children's engagement in oral self-care based on dentists' clinical observations; hence, the requirements for achieving the desired behavior were categorized according to the capability-opportunity-motivation behavior model. Interventional functions were created following the behavior change wheel. A menu-driven chatbot was created and evaluated for usability as well as likeability. Results: The barriers and requirements for achieving good behavior in school-aged children's oral self-care were identified by the dental professionals. Intervention strategy incorporated specific functions enriched with gamification features to support school-aged children in developing their abilities for engaging in oral self-care. The intervention functions consist of capability establishment, motivation enhancement, and opportunity creation, which were designed to support children in their oral self-care practices. The designed chatbot was piloted with a convenient sample of 30 school-aged children and their accompanying parents at the pediatric dental clinic. The results indicated good usability, with a mean usability score of 79.91, and high likeability with a mean score of 4.32 out of 5 for the designed chatbot. Conclusions: The educational chatbot incorporated a combination of clinical dentistry practice and guidelines, aiming to promote oral self-care behavior in school-aged children. The designed chatbot achieved high scores for its usability and user likability.

Development of a Novel Hybrid Suture Anchor for Osteoporosis by Integrating Titanium 3D Printing and Traditional Machining.

The aim of this study is to develop a titanium three-dimensional (3D) printing novel hybrid suture anchor (HSA) with wing structure mechanism which can be opened to provide better holding power for surrounding osteoporotic bone. A screw-type anchor (5.5-mm diameter and 16-mm length) was designed with wing mechanism as well as micro dual-thread in the outer cortex bone contact area and macro single-thread in the anchor body. Both side wings can be opened by an internal screw to provide better bone holding power. The suture anchor and internal screw were manufactured using Ti6Al4V 3D printing and traditional machining, respectively. Static pullout and after dynamic 300-cyclic load (150 N) pullout tests for HSA with or without the wing open and commercial solid anchor (CSA) were performed (n = 5) in severely osteoporotic bone and osteoporotic bone to evaluate failure strengths. Comparison of histomorphometrical evaluation was performed through in vivo pig implantation of HSAs with the wing open and CSAs. The failure strengths of HSA with or without the wing open were 2.50/1.95- and 2.46/2.17-fold higher than those of CSA for static and after dynamic load pullout tests in severely osteoporotic bone, respectively. Corresponding values for static and after dynamic load pullout tests were 1.81/1.54- and 1.77/1.62-fold in osteoporotic bone, respectively. Histomorphometrical evaluation revealed that the effects of new bone ingrowth along the anchor contour for CSA and HSA were both approximately 20% with no significant difference. A novel HSA with wing mechanism was developed using 3D printing and the opened wing mechanism can be used to increase bone holding power for osteoporosis when necessary. Better failure strength of HSA than CSA under static and after dynamic load pullout tests and equivalence of bone ingrowth along the anchor contours confirmed the feasibility of the novel HSA.

Development of an intervention tool for precision oral self-care: Personalized and evidence-based practice for patients with periodontal disease.

BACKGROUND: Oral self-care plays an important role in maintaining oral health and preventing the occurrence of oral diseases. The association between good oral care and good oral hygiene is well known. However, the adherence to a proper daily oral hygiene regimen generally remains poor, so the prevalence of oral diseases remains high. Periodontal disease is the most common oral disease in the population. To enhance the adherence to good oral hygiene behaviors for patients with periodontal disease, we developed a personalized and evidence-based mobile application as an intervention tool for the purpose of initiating and improving good oral self-care. OBJECTIVE: The objective of this study was to demonstrate the systematic development process and content of the oral self-care mobile application, OSCA. METHODS: The systematic development process of OSCA consists of three phases: behavioral diagnosis, intervention design, and assessment of OSCA. Firstly, behavioral problem of oral self-care was identified by the experts in periodontics care. Secondly, the intervention functions and the mode of delivery were designed based on the capability-opportunity-motivation behavioral model, which is the underpinning model behind the behavior change wheel framework. Thirdly, the developed app was evaluated by the experts through a heuristics evaluation checklist by adopting Morville's Honeycomb model, and the final version of OSCA was assessed by the patients with periodontal disease using the System Usability Scale (SUS). RESULTS: The problems of target behavior were identified and incorporated into the design of intervention functions. For the beta version of the OSCA, experts proposed four main suggestions to improve the usefulness. Experts evaluated the beta and final versions of the app using a heuristics evaluation checklist, providing mean scores of 4.38 and 4.62, respectively. For usability testing, 87 participants completed both the specified tasks and the SUS questionnaire, providing an SUS median score of 77.5 (IQR = 12.5) and an overall mean completion time of 12.22 minutes for the specified tasks. The mean scores of the intervention functions for capability establishment, motivation enhancement, and opportunity creation were 6.13, 5.88, and 6.06, respectively. CONCLUSIONS: The study presents a rigorous design process of developing an evidence-based and personalized mobile application for oral self-care. The results of the expert evaluation confirmed the validated design and the participants were satisfied with the designed app.

Biomechanical evaluation of an orthodontic mini-implant with plastic removal cap: an in-vitro experimental testing.

This study evaluates the biomechanical interactions of a mini-implant using a plastic revolving cap (PRC) with translation/rotation features for optional orthodontic traction. An orthodontic mini-implant and the PRC consisting of a hexagon connection onto mini-implant with 60 degree switching unit and an extended arm to provide orthodontic wire tied at different positions. The PRC removal force was measured by pull-out testing. The PRC removal force remained larger than three times the finger pulling force (9.3N) after 5 repeated removal tests. The results for the PRC resistant testing showed that the PRC rotational resistant force (20.31±0.83N) is larger than the maximum traction force (about 4.9N) for orthodontic treatment. The mini-implant used with PRC can provide translation and rotation features to change the angles and directions of orthodontic tractions for most effective anchorage preparation under safety consideration.

Estimation of the failure risk of a maxillary premolar with different crack depths with endodontic treatment by computer-aided design/computer-aided manufacturing ceramic restorations.

INTRODUCTION: This study evaluated the risk of failure for an endodontically treated premolar with different crack depths, which was shearing toward the pulp chamber and was restored by using 3 different computer-aided design/computer-aided manufacturing ceramic restoration configurations. METHODS: Three 3-dimensional finite element models designed with computer-aided design/computer-aided manufacturing ceramic onlay, endocrown, and conventional crown restorations were constructed to perform simulations. The Weibull function was incorporated with finite element analysis to calculate the long-term failure probability relative to different load conditions. RESULTS: The results indicated that the stress values on the enamel, dentin, and luting cement for endocrown restorations exhibited the lowest values relative to the other 2 restoration methods. Weibull analysis revealed that the overall failure probabilities in a shallow cracked premolar were 27%, 2%, and 1% for the onlay, endocrown, and conventional crown restorations, respectively, in the normal occlusal condition. The corresponding values were 70%, 10%, and 2% for the depth cracked premolar. CONCLUSIONS: This numeric investigation suggests that the endocrown provides sufficient fracture resistance only in a shallow cracked premolar with endodontic treatment. The conventional crown treatment can immobilize the premolar for different cracked depths with lower failure risk.

Finite element sub-modeling analyses of damage to enamel at the incisor enamel/adhesive interface upon de-bonding for different orthodontic bracket bases.

This study investigates the micro-mechanical behavior associated with enamel damage at an enamel/adhesive interface for different bracket bases subjected to various detachment forces using 3-D finite element (FE) sub-modeling analysis. Two FE macro-models using triangular and square bracket bases subjected to shear, tensile and torsional de-bonding forces were established using µCT images. Six enamel/adhesive interface sub-models with micro- resin tag morphology and enamel rod arrangement were constructed at the corresponding stress concentrations in macro-model results. The boundary conditions for the sub-models were determined from the macro-model results and applied in sub-modeling analysis. The enamel and resin cement stress concentrations for triangular and square bases were observed at the adhesive bottom towards the occlusal surface under shear force and at the mesial and distal side planes under tensile force. The corresponding areas under torsional force were at the three corners of the adhesive for the triangular base and at the adhesive bottom toward/off the occlusal surface for the square base. In the sub-model analysis, the concentration regions were at the resin tag base and in the region around the etched holes in the enamel. These were perfectly consistent with morphological observations in a parallel in vitro bracket detachment experiment. The critical de-bonding forces damaging the enamel for the square base were lower than those of the triangular base for all detached forces. This study establishes that FE sub-modeling can be used to simulate the stress pattern at the micro-scale enamel/adhesive interface, suggesting that a square base bracket might be better than a triangular bracket. A de-bonding shear force can detach a bracket more easily than any other force with a lower risk of enamel loss.

Estimation of the retainer height biomechanical contribution in posterior resin-bonded fixed partial dentures: a structural-thermal coupled finite element analysis.

This study determines the RBFPD (resin-bonded fixed partial dentures) biomechanical aspects to retainer height using structural-thermal coupled finite element (FE) analysis under normal (37°C) and high (51°C) oral temperatures. Three RBFPD FE models with different retainer heights (100, 75, and 50% of the distance from 2 mm above the CE (cementum-enamel) junction to the occlusal surface) were created using image processing, contour stacking, and mapping mesh procedures. After FE model validation, the maximum first principal and von Mises stresses in the remaining tooth (σ(T)) and prosthesis (σ(P)), were recorded for all models under structural-thermal coupled analyses. The simulation results showed that the σ(T) and σ(p) values decreased with greater retainer height as a result of the increasing prosthesis stiffness and maximizing bonding area between the enamel and retainer at normal oral temperature (37°C). However, no significant stress differences were found according to the retainer height varying dimensions at high (51°C) temperatures. The RBFPD retainer height biomechanical response is dominated by the structural analysis result (at 37°C) and it is recommended that the prosthesis retainer have as great a height as possible to decrease the stress values.

Evaluation of the relative contributions of multi-factors in an adhesive MOD restoration using FEA and the Taguchi method.

OBJECTIVES: This study determines the relative contribution of changes (design factors) in cavity dimension, restorative material, adhesive layer modulus and thickness and loading condition on the biomechanical response of a premolar adhesive Class II MOD restoration. METHODS: A validated finite element (FE) model was used to simulate the mechanical responses. The Taguchi method was employed to identify the significance of each design factor in controlling the stress. RESULTS: The results indicated that the loading condition was the major factor affecting the stress values (49% in tooth and 46% in cement). Cavity depth was found as the second contributor affecting the stress values (31 % in tooth and 30% in cement), followed by resin cement modulus (12% in tooth and 13% in cement). Other factors were found to have no significant effect on the tooth and cement stress values. Increased stress values were found with lateral force, deeper cavity and higher luting cement modulus. SIGNIFICANT: The combined use of FE analysis and the Taguchi method efficiently identified the relative contributions of several restorative factors and indicated that cavity depth was the most critical factor on the cavity dimensions in attaining a proper occlusal adjustment. Reduced lateral occlusal force and lower modulus luting material application are recommended to obtain a better force-transmission mechanism.

Biomechanical interactions in tooth-implant-supported fixed partial dentures with variations in the number of splinted teeth and connector type: a finite element analysis.

OBJECTIVE: The aim of this study was to investigate the biomechanical interactions in tooth-implant-supported fixed partial dentures (FPDs) under several loading conditions with different numbers of splinted teeth and connector types (rigid and non-rigid) by adopting the three-dimensional (3D) non-linear finite element (FE) approach. MATERIAL AND METHODS: A 3D FE FPD model was constructed containing one Frialit-2 implant in the mandibular second-molar region splinted to the first and second premolars. Frictional contact elements were used to simulate realistic interface conditions within the implant system and the non-rigid connector function. The main effects for each level of the three investigated factors (loading condition, number of splinted teeth and connector type) in terms of the stress values and dissimilar mobility of the natural teeth and implant were computed for all models. RESULTS: The results indicated that load condition was the main factor affecting the stress developed in the implant, bone and prosthesis when comparing the type of connector and the number of splinted teeth. The stress values were significantly reduced in centric or lateral contact situations once the occlusal forces on the pontic were decreased. However, the prosthesis stress for the non-rigid connections was increased more than 3.4-fold relative to the rigid connections. Moreover, the average tooth-to-implant displacement ratios (R(TID)) with a non-rigid connection were obviously larger than those for rigid connections under axial loading forces. Adding an extra tooth to support a three-unit tooth-implant FPD only exploited its function when the prosthesis withstood lateral occlusal forces. CONCLUSIONS: The load condition is the main factor affecting stress distribution in different components (bone, prosthesis and implant) of tooth-implant-supported FPDs. Minimizing the occlusal loading force on the pontic area through selective grinding procedures could reduce the stress values obviously. A non-rigid connector may more efficiently compensate for the dissimilar mobility between the implant and natural teeth under axial loading forces but with the risk of increasing unfavorable stresses in the prosthesis.

Factorial analysis of variables influencing mechanical characteristics of a single tooth implant placed in the maxilla using finite element analysis and the statistics-based Taguchi method.

The aim of this study was to determine the relative contribution of changes (design factors) in implant system, position, bone classification, and loading condition on the biomechanical response of a single-unit implant-supported restoration. Non-linear finite-element analysis was used to simulate the mechanical responses in an implant placed in the maxillary posterior region. The Taguchi method was employed to identify the significance of each design factor in controlling the strain/stress. Increased strain values were noted in the cortical bone with lateral force and an implant with a retaining-screw connection. Cancellous bone strain was affected primarily by bone type and increased with decreasing bone density. Implant stress was influenced mainly by implant type and position. The combined use of finite-element analysis and the Taguchi method facilitated effective evaluation of the mechanical characteristics of a single-unit implant-supported restoration. Implants placed along the axis of loading exhibit improved stress/strain distribution. The reduction of lateral stress through implant placement and selective occlusal adjustment is recommended. An implant with a tapered interference fit connection performed better as a force-transmission mechanism than other configurations.

Mechanical interactions of an implant/tooth-supported system under different periodontal supports and number of splinted teeth with rigid and non-rigid connections.

OBJECTIVES: This study investigated the mechanical interactions of implant-teeth splinting systems under different periodontal supports and number of splinted teeth with rigid and non-rigid connectors using non-linear finite element (FE) approach. METHODS: Two FE models with normal and compromised periodontal supports containing a Frialit-2 implant splinted to the first and second premolars were constructed. Non-linear contact elements were used to simulate a realistic interface fixation within the implant system and the sliding function of the non-rigid connector. ANOVA was used to test for relative importance of the investigated factors and main effects for each level of the three investigated factors (periodontal supports, teeth splinting and connector designs) in terms of the stress values were performed. RESULTS: The simulated results indicated that the cross-interaction of the periodontal support and the splinting situation was a major factor affecting the stress value in alveolar bone. An additional splinting decreased the stress values of bone significantly for a compromised periodontal support. The individual factor of periodontal support also influenced the stress found in the alveolar bone (28%) and implant (72%), and the stress values increased when the periodontal support was reduced. Using different connectors affected the stresses found in bone (15%), implant (21%) and prosthesis (99%). The stress values of the implant and prosthesis increased, but were decreased in bone when the splinting system used non-rigid connectors. The mobility of natural teeth and the implant system between non-rigid and rigid connections showed only small differences. CONCLUSIONS: A non-rigid connector should be used with caution since it breaks the stress transfer and increases the unfavorable stress values in the implant system and prosthesis. The tooth/implant-supported system with an additional splinting is more efficient in compromised periodontal supports.

Evaluation of a reinforced slot design for CEREC system to restore extensively compromised premolars.

OBJECTIVES: The structural stability and adhesive strength of a large-cavity premolar with a CEREC restoration is a frequent problem in long-term use. This study sought to determine whether an additional reinforced slot could increase tooth/ceramic retention using finite element (FE) analysis and fracture testing. METHODS: The cavity was designed in a typical MODL restoration failure shape when the lingual cusp has been lost. Two FE restored-tooth models with different cavity designs were created using image processing, contour stacking, and mesh generation. Interfacial (normal and shear) stresses were then calculated with and without the slot design for restored teeth under lateral and axial forces and different interfacial conditions (bonded and de-bonding). For validation, a fracture experiment was performed with and without reinforced slot designs for large ceramic CEREC restorations. RESULTS: The maximum stresses at the buccal wall increased when a lateral occlusal force acted on the restored tooth with a slot design. Conversely, the interfacial stresses decreased when the restored tooth received a uniform axial occlusal force. After de-bonding on the buccal tooth/ceramic interface, the stresses increased by an average factor of three over those obtained with a bonded interface. The fracture forces were consistent with the tendencies predicted in FE analyses. CONCLUSIONS: An additional reinforced slot for the CEREC restoration of a large cavity could increase retention when a restored tooth receives an axial occlusal load. However, the benefits of a slot seem to be doubtful for a premolar often subjected to a lateral load.