Stress Analysis on Mesiolingual Cavity of Endodontically Treated Molar Restored Using Bidirectional Fiber-Reinforced Composite (Wallpapering Technique).

Introduction: Endodontically treated teeth (ETT) undergo extensive structure change and experience high stress during biomechanical function. Stress distribution is influenced by the restoration material and the type of bond between material and tooth structure. The selection of materials that can distribute stress will affect the resistance and retention of ETT to mastication forces, thus biomechanical functions were achieved. Composite has mechanical properties similar to dentin, it can transmit and distribute stresses throughout the tooth surface. The disadvantage of composites in large cavities is their lack of toughness. The addition of fiber to composites can increase their toughness. Purpose: This research is to determine the stress distribution of a fiber-reinforced composite made of polyethylene and e-glass on the mesiolingual cavity of ETT. Materials and Methods: A three-dimensional model of the mandibular molar was prepared for cavity preparation and the formation of restorations using SolidWorks 2021. The models were analyzed with Abaqus 2020 to determine stress concentrations after given vertical and oblique loading. Results: The maximum and minimum principal stress data were obtained to assess material resistance and interfacial damage criterion. Polyethylene fiber shows a more homogeneous stress distribution because the modulus of elasticity is close to the dentin and has a thickness that can reduce the volume of the composite. The E-glass shows the stress concentration on the circumferential fiber and cavity floor. Conclusion: The stress distribution of fiber-reinforced composite on the buccolingual cavity of ETT using the finite element method did not show structural failure in the polyethylene group because the maximum and minimum principal stresses were lower than the strength of the material. Interfacial bond failure occurs at the enamel portion. The maximum and minimum principal values of e-glass indicate structural failure in the circumferential fiber and the base fiber because the stress exceeds the strength of the material. Interfacial bond failure occurred on the circumferential and the cavity floor.

Stress Distribution of Endodontically Treated Tooth MOD Cavity Restored with Ribbon Fiber-Reinforced Composite (Wallpapering Technique) Using Finite Element Method.

Purpose: This research aimed to describe the stress distribution of an endodontically treated tooth with a mesio-occluso-distal (MOD) cavity restored with direct composite reinforced with polyethylene and e-glass ribbon fiber. Methods: This research was a descriptive study using the finite element method. A 3D model of the mandibular first molar solid after endodontic treatment with class II MOD preparation was prepared using Solidworks software. Finite element simulation was carried out using Abaqus software. In the first simulation, 180 N force was applied (vertically 90° perpendicular to the occlusal surface) at four points of loading: the tip of the mesiobuccal and distobuccal cusp, central fossa, and distal marginal ridge. For the second simulation, a 100 N force was applied at a 45° lateral angle to the occlusal surface at two loading points: the lingual slope of the mesiobuccal and distobuccal cusp. Results: This study showed that the stress concentration was located in the occlusal pit and fissure, CEJ distal area, bifurcation in dentin, and the 1/3 cervical area of root dentin. The stress value generated after vertical and lateral force did not exceed the tooth and restoration's compressive and tensile strength value. The failure occurred at the interface of enamel and composite near the loading point area due to vertical load, both on polyethylene and e-glass fiber ribbon-reinforced composite restoration. Stress distribution of an endodontically treated tooth with a MOD cavity restored with ribbon fiber-reinforced composite using the finite element method showed that the highest stress concentration occurred on the surface close to the loading point, in narrow, concave, and sharp areas, and more apically for endodontically treated teeth. Conclusion: Neither the tooth nor restoration failed after vertical and horizontal loads. The interface between enamel and composite on the occlusal surface failed.

The Efficacy of Silver Diamine Fluoride as a Caries Preventive Agent on Permanent Teeth: A Scoping Review.

Dental caries is a chronic condition that affects people of all ages and has a high prevalence in Indonesia. Applying silver diamine fluoride (SDF) as a topical fluoridation agent is one of the approaches to prevent bacterial interactions that lead to the development of carious lesions. This study aims to determine the efficacy of SDF as a caries preventive agent on permanent teeth. Article searches were conducted using the keywords "silver diamine fluoride" AND "permanent tooth OR permanent teeth" AND "caries OR dental caries" AND "remineralize" through digital databases including PubMed, Cochrane Library, Science Direct, and Google Scholar. Articles with randomized controlled trial or nonrandomized controlled trial designs, articles written in Indonesian or English, publications published within the last 5 years (2016-2021), and aligned with the PCC (population, concept, and context) framework were included. Articles that were not accessible in full text or in a paid format, those that were of the meta-analysis or systematic review study type, and those that did not evaluate the use of SDF as a caries preventive agent were excluded from consideration. This scoping review refers to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extensions for Scoping Reviews (PRISMA-ScR) guidelines. A total of 8 articles were reviewed, encompassing various locations, designs, and samples, which demonstrated the use of SDF resulted in a high percentage of fluoride release with a high degree of remineralization efficacy. The deposition of crystals or minerals into fissures and crevices caused by demineralization indicated a reduction in lesion depth and influenced the microhardness of enamel. SDF can stimulate the rehardening of tooth structures rich in calcium and phosphate. The solution of SDF has the potential to serve as an alternative substance for preventing caries in permanent teeth because it enhances mineral precipitation and mineral density, promotes the remineralization of hydroxyapatite in enamel by increasing fluoride, and increases tooth structure resistance to acid attack.

Finite element stress analysis of dental cement application on endocrown and onlay restoration.

The aim of the study was to evaluate the influence of resin cement material types on tooth with endocrown and onlay restorations. The first molar was scanned using Micro-CT and underwent a modelling process to obtain the 3D model for computational simulation. Eight models were simulated in the current study with two loading conditions (720N vertical load and 200N oblique load), two types of restoration (onlay and endocrown restorations), and two resin cement variants (dual-cure resin cement and light-cure resin cement). The tooth with onlay restoration showed a significant stress reduction (up to 70%) when using light-cure resin cement compared to dual-cure resin cement. In contrast, types of cement did not affect stress distribution in the tooth with endocrown restoration. The current study found that dual-cure resin cement was preferable in Endocrown and Onlay restorations, due to dual-cure resin cement provided better bond strength compared to light-cure resin cement.