OBJECTIVES: This study aimed to explore the stress distribution of surface-mounted inlays with two ceramic materials and different strategies for fiber post-restoration on pulp-penetrating non-carious cervical lesion in a maxillary first premolar to provide minimally invasive and reasonable restorative methods. METHODS: The cone beam computed tomography data of the standard right upper first premolar were selected. Healthy control (HC) and defective control (DC) finite element models were established. Then, eight experimental models were established according to two different ceramic materials (IPS e.max CAD [LD] and Lava Ultimate [LU]) and different locations of fiber post (without fiber post [NP], fiber post in buccal root canal [B], fiber post in palatal root canal [P], fiber post in both root canals [BP]), namely, LD_NP, LD_B, LD_P, LD_BP, LU_NP, LU_B, LU_P, and LU_BP. Axial load F1 and lateral load F2 were applied. Maximum principal stress and displacement of the buccal tip were investigated using finite element analysis software. Then, the percentage change of the following indicators in each experimental group was analyzed: stress of defective tip with group DC, stress of enamel and dentine, and displacement of buccal tips with group HC. It was considered similar when the percentage change was less than 5%. RESULTS: LD and LU groups could effectively reduce the stress of the defective tip, but the decreasing amplitude in the former was greater than that of the latter. For the stress of surface-mounted inlays and resin adhesive layer, LD groups were higher than LU groups, and no significant difference in stress peak was found among different experimental groups in the same material. In addition, fiber posts in double root canals could significantly reduce buccal tip displacement. CONCLUSIONS For pulp-penetrating non-carious cervical lesions, the restorative strategy of surface-mounted inlays could be applied. Compared with Lava Ultimate, IPS e.max CAD could better protect the defective tip tooth. Furthermore, fiber posts in double root canals could decrease overall deformation and increase the retention of surface-mounted inlays.
Inlays ; Finite Element Analysis ; Composite Resins ; Bicuspid ; Ceramics ; Dental Stress Analysis

Presbyopia is an age-related condition that progressively decreases the ability to focus on near objects. Minimally invasive surgical techniques have been developed to improve near vision, including laser in situ keratomileuses (LASIK) and corneal inlay. Most have similar approaches using monovision or increasing the depth of focus. Monovision laser refractive surgery is a combination of conventional LASIK, LASIK which creates a multifocal cornea (central near or peripheral near) and aspheric micro-monovision LASIK with a special ablation profile, which develops spherical aberration. Conductive keratoplasty is a method that uses radiofrequency energy to shrink the mid-peripheral corneal stromal tissue. However, it is not used because of regression. A corneal inlay is a small device that is implanted in the corneal flap or pocket made by a femtosecond laser. It is inserted into the non-dominant eye. There are various inlays such as the Flexivue Microlens (refractive), Raindrop (corneal shape-changing), and KAMRA (small-aperture) inlays. However, the safety and effectiveness of these inlays have not been proven over a long follow-up period, so care is required when performing inlay implantation. All presbyopia treatments can improve near vision but also have limitations and side effects such as reduced far vision, contrast sensitivity, or increased glare. Therefore, it is essential to select patients carefully. Mechanisms associated with presbyopia are not fully understood, and presbyopia remains challenging for ophthalmologists.
Contrast Sensitivity ; Cornea ; Corneal Transplantation ; Follow-Up Studies ; Glare ; Humans ; Inlays ; Keratomileusis, Laser In Situ ; Methods ; Presbyopia ; Refractive Surgical Procedures ; Vision, Monocular

Computer aided design and manufacturing and implant surgery using a guide template improve restoration-driven implant treatment procedures. This case utilized those digital technologies to make definitive prostheses for a patient. According to the work flow of digital dentistry, cone beam computed tomography established the treatment plan, which was followed to make the guide template for implant placement. The template guided the implants to be installed as planned. The customized abutments and surveyed fixed restorations were digitally designed and made. The metal framework of the removable partial denture was cast from resin pattern using an additive manufacturing technique, and the artificial resin teeth were replaced with the zirconia onlays for occlusal stability. These full mouth rehabilitation procedures provided functionally and aesthetically satisfactory results for the patient.
Computer-Aided Design ; Cone-Beam Computed Tomography ; Dentistry ; Denture, Partial, Removable ; Humans ; Inlays ; Mouth Rehabilitation* ; Mouth* ; Prostheses and Implants ; Tooth ; Workflow

OBJECTIVE: To investigate the influence of cuspal-coverage thickness on the stress distribution of all-ceramic onlay-restored premolars by using 3D finite element (FE) analysis and to provide references for the design of all-ceramic onlays for clinical application. METHODS: 3D FE models of all-ceramic onlays with three cuspal-coverage thicknesses (2, 3, and 4 mm) of endodontically treated maxillary premolar were constructed based on micro-CT images. Stress distributions in the onlay, adhesive resin cement layer, and dentin of models were analyzed under vertical load (600 N) and oblique load (200 N). RESULTS: When the cuspal-coverage thickness increased, the peak maximum principal stress value decreased inside the onlay but increased in the margin of the adhesive resin cement layer. In addition, stress concentration areas increased in the coronal residual dentin on the palatal side under oblique load. CONCLUSIONS An increase in the cuspal-coverage thickness of all-ceramic onlays may reduce the risk of rupture of the restoration but may deteriorate the restoration and cause palatal dentin fracture.
Bicuspid ; Ceramics ; Composite Resins ; Dental Porcelain ; Dental Stress Analysis ; Finite Element Analysis ; Inlays

This case report describes a technique in which endodontic treatment and permanent indirect restoration were completed in the same clinical appointment with the aid of a computer-aided design/computer-aided manufacturing (CAD/CAM) system. Two patients were diagnosed with irreversible pulpitis of the mandibular first molar. After access preparation, root canals were located, irrigation was performed until bleeding ceased, and the coronal tooth structure was prepared for indirect restoration. Then, utilizing an interim 3-mm build-up of the endodontic access cavity, a hemi-arch digital scan was performed with an intraoral scanner. Subsequent to digital scanning, restoration design was performed simultaneously with the endodontic procedure. The root canals were shaped using the Race system under irrigation with 2.5% sodium hypochlorite followed by root canal filling. The pulp chamber was subsequently filled with a 3-mm-thick composite resin restoration mimicking the interim build-up previously utilized to facilitate block milling in the CAD/CAM system. Clinical try-in of the permanent onlay restoration was followed by acid etching, application of a 5th generation adhesive, and cementation of the indirect restoration. Once the restoration was cemented, rubber dam isolation was removed, followed by occlusal adjustment and polishing. After 2 years of follow-up, the restorations were esthetically and functionally satisfactory, without complications.
Adhesives ; Cementation ; Computer-Aided Design ; Continental Population Groups ; Dental Pulp Cavity ; Endodontics ; Follow-Up Studies ; Hemorrhage ; Humans ; Inlays ; Molar ; Occlusal Adjustment ; Pulpitis ; Rubber Dams ; Sodium Hypochlorite ; Tooth

BACKGROUND: The conventional surgical method for reconstructing orbital floor fractures involves restoration of orbital continuity by covering an onlay with a thin material under the periorbital region. However, in large orbital floor fractures, the implant after inserting is often dislocated, leading to malposition. This study aimed to propose a novel implanting method and compare it with existing methods. METHODS: Among patients who underwent surgery for large orbital floor fractures, 24 who underwent the conventional onlay implanting method were compared with 21 who underwent the novel γ implanting method that two implant sheets were stacked and bent to resemble the shape of the Greek alphabet γ. When inserting a γ-shaped implant, the posterior ledge of the orbital floor was placed between the two sheets and the bottom sheet was impacted onto the posterior wall of the maxilla to play a fixative role while the top sheet was placed above the residual orbital floor to support orbital contents. Wilcoxon signed-rank test and Mann-Whitney U test were used for data analyses. RESULTS: Compared to the conventional onlay method, the gamma method resulted in better restoration of orbital contents, better improvement of enophthalmos, and fewer revision surgeries. CONCLUSION: Achieving good surgical outcomes for extended orbital floor fractures is known to be difficult. However, better surgical outcomes could be obtained by using the novel implantation method of impacting a γ-shaped porous polyethylene posteriorly.
Enophthalmos ; Humans ; Inlays ; Maxilla ; Methods ; Orbit ; Orbital Fractures ; Orbital Implants ; Polyethylene ; Statistics as Topic

BACKGROUND AND OBJECTIVES: Inlay butterfly cartilage tympanoplasty makes the graft easy, and reduces operating time. The present study aimed to investigate the outcomes of microscopic versus endoscopic inlay butterfly cartilage tympanoplasty. SUBJECTS AND METHODS: In this retrospective study, the outcomes of 63 patients who underwent inlay butterfly cartilage tympanoplasty with small to medium chronic tympanic membrane perforation were evaluated. Twenty-four patients underwent conventional microscopic tympanoplasty and 39 underwent endoscopic tympanoplasty. The outcomes were analyzed in terms of the hearing gain and graft success rate. RESULTS: The surgical success rate was 95.8% in the patients who underwent conventional microscopic tympanoplasty and 92.3% in those who underwent endoscopic tympanoplasty. In both groups of patients, the postoperative air-bone gap (ABG) was significantly lower than the preoperative ABG. There were no significant differences between the preoperative and postoperative ABG values in either group. CONCLUSIONS: Endoscopic inlay tympanoplasty using the butterfly cartilage technique appears to be an effective alternative to microscopic tympanoplasty and results in excellent hearing.
Butterflies ; Cartilage ; Endoscopy ; Hearing ; Humans ; Inlays ; Microscopy ; Retrospective Studies ; Transplants ; Tympanic Membrane Perforation ; Tympanoplasty

OBJECTIVE: To analyze the effect of ceramic onlay to repair serious defects in young permanent molars. METHODS: Sixty patients with defects in young permanent molars were selected. The patients were randomly divided into two groups. One group was restored with ceramic onlay, and the other used resin composite to direct filling. Follow-up visit was conducted at 3, 6, 12, and 24 months after treatment. Modified USPHS/Ryge criteria were used to evaluate the effect of restoration. The occlusal courses were recorded by the T-Scan Ⅲ system in intercuspal position. Gingival and food impaction were recorded. The effect of the two restorative methods, the recovery of occlusal function, and the gingival and approximal conditions were analyzed. RESULTS: At 12 months after restoration, the marginal fitness in the onlay group was significantly better than that in the resin group (P<0.05). At 12 and 24 months after restoration, the surface smoothness in the onlay group was significantly better than that in the resin composite group (P<0.05). At each follow-up visit, the resin group had significantly lower per-cen-tage of occlusal force than contralateral molar (P<0.05). The percentage of occlusal force in the onlay group and the con-trala-teral molar showed no statistical difference (P>0.05). The gingival and approximal conditions also demon-strated no stati-stical differences (P>0.05). CONCLUSIONS The ceramic onlay repair method is better than resin composite filling in marginal fitness, surface smoothness, and recovery of the occlusal function when restoring young permanent molars with serious defects.
Bite Force ; Ceramics ; Composite Resins ; Dental Restoration, Permanent ; methods ; Humans ; Inlays ; Molar ; Resin Cements

The computer-aided design/computer-aided manufacturing (CAD/CAM) system was introduced to shorten the production time of all-ceramic restorations and the number of patient visits. Among these types of ceramic for dental CAD/CAM, they have been processed into inlay, onlay, and crown shapes using leucite-reinforced glass-ceramics to improve strength. The purpose of this study was to observe the mechanical properties and microstructure of leucite-reinforced glass-ceramics for dental CAD/CAM. Two types of leucite-reinforced glass-ceramic blocks (IPS Empress CAD, Rosetta BM) were prepared with diameter of 13 mm and thickness of 1 mm. Biaxial flexural testing was conducted using a piston-on-three-ball method at a crosshead speed of 0.5 mm/min. Weibull statistics were used for the analysis of biaxial flexural strength. Fracture toughness was obtained using an indentation fracture method. Specimens were observed by field emission scanning electron microscopy to examine the microstructure of the leucite crystalline phase after acid etching with 0.5% hydrofluoric acid aqueous solution for 1 minute. The results of strength testing showed that IPS Empress CAD had a mean value of 158.1±8.6 MPa and Rosetta BM of 172.3±8.3 MPa. The fracture toughness results showed that IPS Empress CAD had a mean value of 1.28±0.19 MPa·m(1/2) and Rosetta BM of 1.38±0.12 MPa·m(1/2). The Rosetta BM sample exhibited higher strength and fracture toughness. Moreover, the crystalline phase size and ratio were increased in the Rosetta BM sample. The above results are expected to elucidate the basic mechanical properties and crystal structure characteristics of IPS Empress CAD and Rosetta BM. Additionally, they will help develop leucite-reinforced glass-ceramic materials for CAD/CAM.
Ceramics ; Crowns ; Crystallins ; Humans ; Hydrofluoric Acid ; Inlays ; Methods ; Microscopy, Electron, Scanning

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