Journal of prosthodontic research最新文献

Patient: A 67-year-old woman presented with severe periodontitis-induced terminal dentition and proclined maxillary incisor. Three-dimensional facial esthetics-driven computer-assisted virtual tooth rearrangement was performed for implant-supported full-arch reconstruction. The digital workflow combines facial and spiral computed tomography (CT) scans to generate a virtual patient for three-dimensional (3D) facial analysis and obtain a visual treatment objective (VTO)-based lateral esthetic preview for virtual teeth rearrangement. Subsequently, this printed interim denture performed well in functionalization and esthetics, acted as a transitional removable denture, radiological template, and implant-supported interim denture, and guided the design of the final restoration.

Discussion: Conventional methods for lateral esthetic preview, such as traditional wax rim try-in, confront difficulties in the treatment of terminal dentition, especially in the presence of proclined maxillary incisors. However, currently available software that aids information fusion and facial analysis can accurately predict soft-to-hard tissue movement and efficiently guide virtual tooth rearrangement for implant-supported full-arch reconstruction.

Conclusions: The use of VTO-based lateral esthetic preview for implant-supported reconstruction improves pre- and postoperative information transfer accuracy and doctor-patient communication efficiency.

Purpose: To investigate survival rates and technical and biological complications of one-piece screw-retained hybrid abutments in implant-supported single crowns (SCs).

Study selection: An electronic search was performed on five databases for clinical studies involving implant-supported single hybrid abutment crowns constructed using titanium-base (Ti base) abutments, with at least 12 months of follow-up. The RoB 2, Robins-I, and JBI tools were used to assess the risk of bias for the different study types. Success, survival, and complication rates were calculated, and a meta-analysis was performed to obtain a pooled estimate. Peri-implant health parameters were extracted and analyzed.

Results: 22 records (20 studies) were included in this analysis. Direct comparisons between screw-retained hybrid abutment SCs and cemented SCs showed no significant differences in the 1-year survival and success rates. For SCs using a hybrid abutment crown design, their 1-year survival rate was 100% (95% CI: 100%-100%, I² = 0.0%, P = 0.984), and a success rate of 99% (95% CI: 97%-100%, I² = 50.3%, P = 0.023) was calculated. No confounding variables significantly affected the estimates. The individual technical complication rate was low at 1-year follow-up. The estimated incidence of all types of complications in hybrid abutment SCs is less than 1%.

Conclusions: Within the limitations of this study, implant-supported SCs using a hybrid abutment crown design showed favorable short-term clinical outcomes. Additional well-designed clinical trials with at least a 5-year observation period are required to confirm their long-term clinical performance.

Purpose: This study aimed to synthesize heat-cured poly(methyl methacrylate) (PMMA) acrylic formulated with copper nanoparticles (nCu) for producing dentures with antimicrobial properties and ability to prevent denture stomatitis (DS).

Methods: nCu/PMMA nanocomposites were prepared through in situ formation of nCu into methyl methacrylate (MMA). The fabricated material was characterized using scanning electron microscopy, spectroscopy (energy-dispersive X-ray, attenuated total reflectance-Fourier-transform infrared, and X-ray photoelectron spectroscopy), X-ray diffraction analysis, and mechanical flexural tests (ISO 20795-1:2008). Antimicrobial activity against Candida albicans and oral bacteria was determined. MTS assay (ISO 10993-5:2009) and copper release experiments were conducted to assess cytotoxicity. In the clinical trial, participants wearing nCu/PMMA (n=25) and PMMA (n=25) dentures were compared; specifically, DS incidence and severity and Candida species proliferation were assessed for 12 months. Data were analyzed using analysis of variance with Tukey's post hoc test (α=0.05).

Results: nCu/PMMA nanocomposite loaded with 0.045% nCu exhibited the maximum antimicrobial activity against C. albicans and other oral bacteria without producing cytotoxicity in the wearer. nCu/PMMA dentures retained their mechanical and aesthetic properties as well as inhibited the growth of Candida species on both denture surface and patient palate. DS incidence and severity were lower in the nCu/PMMA denture group than in the PMMA denture group.

Conclusions: PMMA acrylic produced with copper nanotechnology is antimicrobial, biocompatible, and aesthetic and can reduce DS incidence. Thus, this material may act as a novel preventive alternative for oral infections associated with denture use.

Purpose: This scoping review aimed to systematically map research regarding implant-assisted removable partial dentures (IARPDs), and identify existing gaps in knowledge.

Study selection: Two reviewers independently conducted a search of the MEDLINE-PubMed and Scopus databases according to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) extension for Scoping Review and included articles published in English up to August 31, 2022, including human studies, reviews, and in vitro studies. Expert opinions, animal studies, and clinical studies involving complete overdentures were excluded, and ten aspects for establishing the treatment strategy for IARPDs were examined.

Results: One hundred and twelve articles were chosen. There were two treatment modalities: IARPDs retained by implant- and tooth-supported surveyed single crowns (SCs) or fixed partial dentures (FPDs). In IARPDs retained by tooth-supported surveyed SCs or FPDs, the survival rate of dental implants for IARPDs was relatively higher with a wide range of marginal bone loss and many complications, but with improved functional performance, oral health-related quality of life, and patient satisfaction. There were limited data on survival or success rates and designs of IARPDs, attachment selections, length and diameter, inclination, placement sites, and loading protocols of implants, regardless of prosthetic types. There was limited information on maxillary IARPDs except for survival rates of implants.

Conclusions: Although IARPDs could become a useful treatment strategy, there is limited scientific consensus with gaps in knowledge about their use. Additional well-designed clinical and in vitro studies are necessary to scientifically establish IARPDs as definitive prostheses in implant dentistry.

Purpose: This systematic review aimed to evaluate the effects of implant placement sites on the biomechanical behavior of implant-assisted removable partial dentures (IARPDs) using finite element analysis (FEA).

Study selection: Two reviewers independently conducted manual searches of the PubMed, Scopus, and ProQuest databases for articles investigating implant location in IARPDs using FEA, according to the 2020 Systematic Reviews and Meta-analyses statement. Studies published in English up to August 1, 2022, were included in the analysis based on the critical question.

Results: Seven articles meeting the inclusion criteria were systematically reviewed. Six studies investigated mandibular Kennedy Class I and one study investigated mandibular Kennedy Class II. Implant placement reduced the displacement and stress distribution of the IARPD components, including dental implants and abutment teeth, regardless of the Kennedy Class type and dental implant placement site. Most of the included studies showed that, based on the biomechanical behavior, the molar region, rather than the premolar region, is the preferred implant placement site. None of the selected studies investigated the maxillary Kennedy Class I and II.

Conclusions: Based on the FEA regarding mandibular IARPDs, we concluded that implant placement in both the premolar and molar regions improves the biomechanical behaviors of IARPD components, regardless of the Kennedy Class. Implant placement in the molar region results in more suitable biomechanical behaviors compared with implant placement in the premolar region in Kennedy Class I. No conclusion was reached for Kennedy Class II due to the lack of relevant studies.

Purpose: This study aimed to elucidate the relationship between diurnal masseter muscle activity and awareness of diurnal awake bruxism (d-AB) by conducting a comparative analysis of electromyographic (EMG) data from individuals with and without awareness of diurnal awake bruxism (d-AB), utilizing EMG data gathered from multiple subjects.

Methods: Unilateral masseter electromyography (EMG) recordings were performed during the daytime using an ultraminiature wearable EMG device. A total of 119 participants (59 with awareness of diurnal tooth clenching [d-TC] and 60 without awareness of d-TC) were included. Waveforms longer than 0.25 s with the two amplitude conditions, exceeding twice the baseline and >5% of maximum voluntary clenching, were extracted. In addition, the number of bursts and episodes (groups of bursts), burst duration, and burst peak amplitude were calculated for each participant.

Results: There were no significant differences in the EMG parameters between the groups with and without awareness of d-TC. Additionally, the frequency distribution of the number of EMG waveforms exhibited wide ranges and substantial overlap between the two groups.

Conclusions: The variability in the number of bursts and episodes, burst peak amplitude, and burst duration among subjects suggests the need for an objective classification of d-AB severity based on EMG values. The absence of significant differences and large overlap in frequency distributions between the groups with and without awareness of d-TC indicate difficulty in predicting muscle activity solely based on awareness of d-AB.

Purpose: This narrative review aimed to survey the clinical outcomes of laminate veneers (LVs), including their survival and success rates.

Study selection: An electronic search of MEDLINE/PubMed, Web of Science, Cochrane Library, and Google Scholar from 2000 to April 2023 was conducted using the keywords “laminate” OR “veneer” OR “porcelain” OR “feldspathic” OR “lithium disilicate” OR “composite resin” OR “zirconia” OR “survival” OR “success.” Case reports, case series, reviews, abstracts, in vitro studies, and observational studies were excluded. Five researchers independently evaluated the titles and abstracts of all identified studies.

Results: A total of 55 studies were identified. None of the studies met the criteria for zirconia LVs. According to the studies in this review, LVs fabricated with feldspathic porcelain, leucite-reinforced glass ceramics (LRG), and lithium disilicate ceramics (LDS) exhibited satisfactory survival and success rates. Furthermore, hydrofluoric acid etching followed by silane priming of the surface of ceramic LVs is necessary for improved clinical outcomes. The extent of dentin exposure significantly decreases the success rate of ceramic LVs. An appropriate adhesive luting process is required to achieve the long-term success of ceramic LVs. Dentin exposure should be minimized or sealed during tooth preparation to achieve a reliable and durable bond between LVs and abutment teeth.

Conclusions: Based on this narrative review of the literature, the use of silica-based ceramic feldspathic porcelain, LRG, and LDS is recommended for LVs.

Purpose: This study aimed to investigate the retentive force and deformation of double Akers’ polyetherketoneketone (PEKK) clasps on removable partial dentures (RPDs) with varying designs and undercut depths.

Methods: Thirty double Akers’ PEKK clasps with two different widths and heights (Groups I and II) were fabricated using computer-aided design and computer-aided manufacturing (CAD/CAM). Each design was further subdivided (n = 5) into three undercut depths (0.25, 0.50, and 0.75 mm). The retentive force of the clasps was measured after 10 years of clinical use (15,000 insertion/removal cycles), and the deformation of the clasp tips was analyzed before and after cycling.

Results: Clasps with 0.50-mm and 0.75-mm undercut depths exhibited greater initial retentive forces (3.15–3.51 N) compared to those in the 0.25-mm undercut group (2.40–2.80 N). Group I maintained consistent retentive forces over the cycles (P = 0.345), whereas Group II showed declining forces after the initial use (P < 0.003). In both groups, the 0.50-mm undercut exhibited a greater retentive force than the 0.25-mm (P < 0.001 and P < 0.004, respectively), with no significant differences between the 0.50-mm and 0.75-mm undercut depths. Despite a lower initial retentive force, the 0.25-mm undercut showed less deformation and clasp tip wear.

Conclusions: The PEKK clasps did not exhibit significantly reduced retentive forces or permanent deformations after 15,000 fatigue cycles. These results suggest that the PEKK polymer displays superior mechanical properties as an esthetic clasp material, and clasps with 0.50-mm and 0.75-mm undercut depths are recommended for long-term clinical use.

Purpose: To describe a novel digital design technique for creating an individualized emergence profile for implant restoration based on the contralateral tooth.

Methods: Cone beam computed tomography (CBCT) data were used to accurately obtain a three-dimensional (3D) model of the contralateral tooth, which was mirror-flipped to design the emergence profile. The emergence profile was further divided into critical and subcritical areas; the critical area precisely replicated the mirror-flipped 3D model, whereas the subcritical area featured a slight concavity on the buccal side, flatness on the lingual side, and slight convexity on the mesial and distal surfaces. Subsequently, a milling machine was used to fabricate healing abutments with individualized emergence profiles. The design of the definitive restoration completely duplicated the emergence profile of the individualized healing abutment and was fabricated using a milling machine.

Conclusions: This technical procedure presents an alternative novel method for designing the emergence profiles of implant restorations, with the potential to improve esthetics and functions as well as to maintain the long-term stability of peri-implant soft and hard tissues.

Purpose: The aim of this study was to establish and assess the validity of in silico models of biaxial flexural strength (BFS) tests to reflect in vitro physical properties obtained from two commercially available computer-aided design/computer-aided manufacturing (CAD/CAM) ceramic blocks and one CAD/CAM resin composite block.

Methods: In vitro three-point bending and BFS tests were conducted for three CAD/CAM materials (n = 10): Katana Zirconia ST10 (raw material: super-translucent multilayered zirconia, ST10; Kuraray Noritake Dental, Niigata, Japan), Katana Zirconia HT10 (raw material: highly translucent multilayered zirconia, HT10; Kuraray Noritake Dental), and Katana Avencia N (AN; Kuraray Noritake Dental). Densities, flexural moduli, and fracture strains were obtained from the in vitro three-point bending test and used as an input for an in silico nonlinear finite element analysis. The maximum principal stress (MPS) distribution was obtained from an in silico BFS analysis.

Results: The elastic moduli of AN, HT10, and ST10 were 6.513, 40.039, and 32.600 GPa, respectively. The in silico fracture pattern of ST10 observed after the in silico evaluation was similar to the fracture pattern observed after the in vitro testing. The MPS was registered in the center of the tensile surface for all three specimens. The projections of the supporting balls were in the form of a triple asymmetry.

Conclusions: The in silico approach established in this study provided an acceptable reflection of in vitro physical properties, and will be useful to assess biaxial flexural properties of CAD/CAM materials without wastage of materials.