PURPOSE: This study aimed to analyze stress distribution and maximum von Mises stress generated in intracoronal restorations and in tooth structures of mandibular molars with various types of cavity designs and materials. MATERIALS AND METHODS: Threedimensional solid models of mandible molar such as O inlay cavity with composite and gold (OR-C, OG-C), MO inlay cavity with composite and gold (MR-C, MG-C), and minimal invasive cavity on occlusal and proximal surfaces (OR-M, MR-M) were designed. To simulate masticatory force, static axial load with total force of 200 N was applied on the tooth at 10 occlusal contact points. A finite element analysis was performed to predict stress distribution generated by occlusal loading. RESULTS: Restorations with minimal cavity design generated significantly lower values of von Mises stress (OR-M model: 26.8 MPa; MR-M model: 72.7 MPa) compared to those with conventional cavity design (341.9 MPa to 397.2 MPa). In tooth structure, magnitudes of maximum von Mises stresses were similar among models with conventional design (372.8 – 412.9 MPa) and models with minimal cavity design (361.1 – 384.4 MPa). CONCLUSION: Minimal invasive models generated smaller maximum von Mises stresses within restorations. Within the enamel, similar maximum von Mises stresses were observed for models with minimal cavity design and those with conventional design.
Bite Force ; Dental Enamel ; Finite Element Analysis ; Inlays ; Mandible ; Molar ; Tooth

PURPOSE: This study aims to analyze the stress distribution of mandibular molar restoration supported by the implants with external hex and internal taper abutment connection design. MATERIALS AND METHODS: Models of external connection (EXHEX) and internal connection (INCON) implants, corresponding abutment/crowns, and screws were developed. Supporting edentulous mandibular bony structures were designed. All the components were assembled and a finite element analysis was performed to predict the magnitude and pattern of stresses generated by occlusal loading. A total of 120 N static force was applied both by axial (L1) and oblique (L2) direction. RESULTS: Peak von Mises stresses produced in the implants by L2 load produced 6 – 15 times greater than those by L1 load. The INCON model showed 2.2 times greater total amount of crown cusp deflection than the EXHEX model. Fastening screw in EXHEX model and upside margin of implant fixture in INCON model generated the peak von Mises stresses by oblique occlusal force. EXHEX model and INCON model showed the similar opening gap between abutment and fixture, but intimate sealing inside the contact interface was maintained in INCON model. CONCLUSION: Oblique force produced grater magnitudes of deflection and stress than those by axial force. The maximum stress area at the implant was different between the INCON and EXHEX models.
Bite Force ; Crowns ; Finite Element Analysis* ; Molar

Fabrication of complete denture by Jiro Abe's method was introduced that enhance the retention and stability of denture by sealing around the denture border with mucous membrane to make negative pressure at the inner surface of denture base when swallowing or occlusion. In this case, taking impression and fabricating complete denture by the Jiro Abe's method for an edentulous patient with severe mandibular alveolar bone resorption allowed us to obtain clinically enhance stability of denture and improve satisfaction of patient.
Alveolar Process* ; Bone Resorption ; Deglutition ; Denture Bases ; Denture, Complete* ; Dentures ; Humans ; Mucous Membrane

Adoption of CAD/CAM milling in dentistry has allowed production of more analytic and precise prosthesis. Such precision enables definite path of insertion and undercut to be provided in removable partial denture especially when designing a surveyed crown on an abutment tooth. This case is about the production of surveyed crown with proper path of insertion utilizing CAD/CAM electronic surveying method on a patient with edentulous maxilla. Resulting removable partial denture fit well and showed acceptable stability and retention with no clinical problem.
Crowns* ; Dental Prosthesis* ; Dentistry ; Denture, Partial, Removable ; Humans ; Maxilla ; Methods ; Prostheses and Implants ; Tooth

The Gothic arch tracing method using a Gothic arch tracer which is one of the centric relation recording methods can reproduce mandibular movement more accurately by describing the path of mandibular curvilinear motion. This case reports that we have satisfactory results by recording reproducible centric relation using a gothic arch tracing method in a patient who has difficulty to induce centric relation by operator due to parafunctional movement.
Centric Relation* ; Humans ; Mouth Rehabilitation* ; Mouth*

Loss of posterior support may cause extrusion of antagonistic teeth and excessive wear of remaining teeth which often leads to the destruction of the occlusal plane. In such cases, it is critical to verify the need to increase vertical dimension of occlusion (VDO). Should you increase VDO, provisionalization is crucial in evaluating function and esthetics. Double scanning technique is a useful method when fabricating definitive restoration that mimic provisional restoration. In this case, a patient with apparently no loss of VDO and insufficient interocclusal space for dental materials due to loss of posterior support and extrusion of antagonistic teeth was rehabilitated using double scanning technique.
Dental Materials ; Dental Occlusion ; Esthetics ; Humans ; Methods ; Rehabilitation* ; Tooth ; Vertical Dimension

With development of digital dentistry, the 3-dimensional (3D) manufacturing industry using computer-aided design and computer-aided manufacturing (CAD/CAM) has grown dramatically in recent years. Denture fabrication using digital method is also increasing due to the recent development of digital technology in dentistry. The 3D manufacturing process can be categorized into 2 types: subtractive manufacturing (SM) and additive manufacturing (AM). SM, such as milling is based on cutting away from a solid block of materal. AM, such as 3D printing, is based on adding the material layer by layer. AM enables the fabrication of complex structures that are difficult to mill. In this case, additive manufacturing method was applied to the fabrication of the resin-based complete denture to a 80 year-old patient. During the follow-up periods, the denture using digital method has provided satisfactory results esthetically and functionally.
Computer-Aided Design ; Dentistry ; Denture, Complete ; Dentures ; Follow-Up Studies ; Humans ; Methods ; Printing, Three-Dimensional

PURPOSE: To analyze stress distribution in premolars restored with inlays or onlays using various materials. MATERIALS AND METHODS: Three-dimensional maxillary premolar models of abutments were designed to include the following: 1) inlay with O cavity (O group), 2) inlay with MO cavity (MO group), 3) inlay with MOD cavity (MOD group), and 4) onlay (ONLAY group). A restoration of each inlay or onlay cavity was simulated using gold alloy, e.max ceramic, or composite resin for restoration. To simulate masticatory forces, a total of 140 N static axial force was applied onto the tooth at the occlusal contact areas. A finite element analysis was performed to predict the magnitude and pattern of stresses generated by occlusal loading. RESULTS: Maximum von Mises stress values generated in the abutment teeth of the ONLAY group were ranged from 26.1 to 26.8 MPa, which were significantly lower than those of inlay groups (O group: 260.3–260.7 MPa; MO group: 252.1–262.4 MPa; MOD group: 281.4–298.8 MPa). Maximum von Mises stresses generated with ceramic, gold, and composite restorations were 280.1, 269.9, and 286.6 MPa, respectively, in the MOD group. They were 252.2, 248.0, 255.1 MPa, respectively, in the ONLAY group. CONCLUSION: The onlay design (ONLAY group) protected tooth structures more effectively than inlay designs (O, MO, and MOD groups). However, stress magnitudes in restorations with various dental materials exhibited no significant difference among groups (O, MO, MOD, ONLAY).
Alloys ; Bicuspid ; Bite Force ; Ceramics ; Dental Materials ; Finite Element Analysis ; Inlays ; Tooth

Conventional denture impression techniques have limitations for edentulous patients with severe alveolar bone resorption and can cause problems from excessive border extension. Especially when a patient has movable tissue it is difficult to make accurate impression, thus might interrupt stable seating of complete denture. Fabrication of complete denture using closed mouth technique for edentulous patient with severe ridge resorption is thought to provide better stability and retention. In this case, an 86-year-old patient had both edentulous jaws with epulis fissuratum on maxillary anterior ridge and severe mandibular ridge resorption. Thus, tentative vertical dimension was determined by using Centric tray and individual tray attached with gothic arch tracer was fabricated. Complete denture was fabricated using closed mouth technique and the patient was satisfied with better stability and retention of the complete denture.
Aged, 80 and over ; Bone Resorption ; Denture, Complete* ; Dentures ; Gingival Diseases ; Humans ; Jaw, Edentulous ; Mouth* ; Vertical Dimension

Fabrication of complete denture with suction mechanism was introduced to enhance the retention and stability of denture by sealing around the denture border by formingnegative pressure on the inner side of denture base during functional movement such as swallowing or masticating. Mandibular suction dentures reduce denture dislodgingforce during opening by taking preliminary impression without pressure on retromolar pad area in rest position. In this case, fabrication of complete denture using suctionmechanism for an edentulous patient with severe alveolar bone resorption allowed us to clinically enhance retention and stability of denture and improve satisfaction ofpatient. (J Korean Acad Prosthodont 2020;58:130-6)