The International Journal of Prosthodontics, 02/2024

Peri-implant diseases are defined as bacterial plaque-induced inflammatory conditions affecting implant-surrounding tissues and are classified as peri-implant mucositis and peri-implantitis. Peri-implant mucositis is characterized by an inflammatory lesion that resides in the soft tissue compartment, whereas at peri-implantitis sites the lesions also feature progressive loss of implant-supporting bone. Inflammation resolution and disease progression arrestment are the main therapeutic endpoints of the treatment of peri-implant diseases. The present position paper displays the current evidence and clinical recommendations of the European Association for Osseointegration for the treatment of peri-implant diseases. Mechanical biofilm removal along with the reinforcement of patient-administered oral hygiene is considered the standard treatment for managing peri-implant mucositis. It is recommended to assess the outcomes of peri-implant mucositis treatment 2 to 3 months after therapy, and repeated intervention should be considered in the absence of treatment success. Peri-implantitis treatment should follow a stepwise treatment approach, starting with nonsurgical treatment followed by surgical intervention, if that is not sufficient. Surgical peri-implantitis therapies include nonreconstructive, reconstructive, and combined treatment modalities. Implantoplasty may be advocated for the treatment of supracrestal peri-implant defects, whereas reconstructive therapy is indicated at peri-implantitis sites featuring intraosseous defects with a depth ≥ 3 mm. Adjunctive reconstructive measures may be beneficial in enhancing radiographic defect fill and maintaining postoperative soft tissue levels, which may have a great impact in esthetic cases. The adjunctive use of systemic antibiotics during surgical therapy does not seem to improve the clinical outcomes. Regular supportive peri-implant therapy with biofilm removal should be an integral part of the treatment protocol for peri-implant diseases. In the presence of advanced bone loss around implants that do not play a strategic role in masticatory function, implant removal may be considered immediately.

Purpose: To study the degree of accuracy in gingival shade matching of undergraduate students using a computer application. Materials and Methods: In total, 76 undergraduate dental students' gingival shade selection abilities were evaluated using an in-house developed computer application. A total of 15 intraoral gingival photographs and 21 pink gingival color porcelain samples were used. The environmental conditions were standardized, and no time limit was set for answering in the computer application. Results: Fourteen gingival color samples (66.6%) were not useful for representing the studied gingival shades. Not all natural gingival colors studied were represented within the 50.50% acceptability limits of the pink samples. There were no statistically significant differences between men and women in terms of “hit” percentages. The highest correlation coefficient (in absolute value) was for the L* coordinate (the darker the gingiva in the picture, the higher the hit rate for choosing the “ideal” shade tab); however, none of the linear correlation coefficients were statistically significant. Conclusions: Not all colors provided in the pink ceramic system were useful for subjective gingival selection. There were no statistically significant differences between male and female dental students in gingival color perception. The L* coordinate was the only one that influenced the correct perception of gingival color by dental students, and it did so more in women than in men.

Purpose: To investigate the long-term predictability of simplifying mandibular overdenture treatment using single-stage surgery and immediate prosthetic loading of a single implant to provide a more affordable treatment option. Materials and Methods: A total of 29 patients with a mean age of 68 years with problematic mandibular dentures were treated. A single implant (Brånemark System Mklll TiUnite, Nobel Biocare) was placed into the mandibular midline for primary stability. A ball attachment was placed, and the retentive cap was incorporated into the existing denture. The patients were recalled at 3 and 12 months and at 3, 5, 10, and 15 years. Clinical assessments, radiographs, and resonance frequency analysis were recorded. All complications, failures, maintenance, and reasons for failure to follow-up were noted. Visual analog scale (VAS) questionnaires were used to record patient satisfaction (ANOVA; P < .05). Results: One implant did not achieve sufficient primary stability to be immediately loaded and was treated with a two-stage delayed loading protocol. Of the 28 patients receiving immediately loaded implants, 14 patients were available for follow-up at 15 years. Implant survival remained at 100% throughout the study. Patient satisfaction was high, with a significant increase in all comfort and functional parameters (P values ranged from < .001 to .07) throughout the 15-year period. Conclusions: These 15-year results indicate that immediate loading of a single oxidized surface implant used to retain a mucosa-borne overdenture is a safe, reliable, and cost-effective treatment with high levels of patient satisfaction long term.

Purpose: To assess the effectiveness of converting a conventional mandibular denture (CMD) into a single-implant mandibular overdenture (SIMO). Materials and Methods: Edentulous patients received a new CMD and were randomly assigned to the CMD or SIMO group. For SIMO patients, a midline early-loaded implant was inserted and incorporated into the CMD after 3 weeks. Patient satisfaction and oral health–related quality of life were assessed at baseline and up to 1 year. Regression models were constructed using Generalized Estimating Equation (GEE). Results: After 12 months, 32 patients were assessed (CMD: n = 17; SIMO: n = 15). Significant improvement was observed for the SIMO group compared to baseline measures. Conclusions: SIMO may be considered an effective alternative for patients unsatisfied with their CMDs.

Purpose: To generate data on the long-term survival of metal-ceramic resin-bonded fixed partial dentures (RBFPDs). Materials and Methods: A total of 89 patients received 94 RBFPDs, 5 of whom (women n = 1; men n = 4) received 2 RBFPDs each. All RBFPDs were fabricated as two-retainer end-abutment metal-ceramic restorations. Clinical follow-ups were performed 6 months after cementation and then annually thereafter. The mean observation time was 7.5 years. Cox regression was performed to test the effects of the variables: gender, location, arch, design, use of rubber dam, and adhesive luting system. Survival and success were calculated using Kaplan-Meier curves. As a secondary objective, patient and dentist satisfaction with the esthetics and function of the RBFPDs was evaluated. The significance level was set at α = .05 for all calculations. Results: Estimated Kaplan-Meier failure-free survival was 97.5% (standard error [SE] 1.7) after 5 years and 83.3% (SE 5.3) after 10 years. Calculated intervention-free survival (success) was 90.1% (SE 3.4) after 5 years and 65.5% (SE 6.7) after 10 years. Debonding-free survival was 92.6% (SE 2.9) after 5 years and 80.6% (SE 5.4) after 10 years. Cox regression revealed that none of the four tested variables had a significant effect on the incidence of complications in RBFPDs. Patient and dentist satisfaction with RBFPD esthetics and function was consistently high throughout the observation period. Conclusions: Within the limitations of an observational study, RBFPDs achieved clinically successful outcomes over a mean observational period of 7.5 years.

Purpose: To identify pressure areas using an impression technique and to evaluate whether adjustment of dentures prior to installation can decrease ulcer frequency, reduce the number of adjustments, and improve satisfaction with treatment. Materials and Methods: A total of 50 complete denture users were selected and randomly divided into two groups. Pressure areas were identified in 25 subjects using the impression technique with fluid silicone, and the denture base in these areas was adjusted before installation. A total of 25 patients received new complete dentures without adjustments before installation. The number of ulcers observed was registered at 1, 7, 15, and 30 days after installation. Patient satisfaction was registered before installation and 1 month after installation. The number of necessary postinstallation adjustments was considered. Comparisons between the groups with respect to the number of ulcers and adjustments and patient satisfaction were performed using the Mann-Whitney test. Results: Identification of pressure areas reduced the number of ulcers after installation of the new prostheses. These results were observed in the 1- (P = .004) and 7-day (P = .002) adjustments for the maxilla and in all the adjustments for the mandible. The technique improved patient satisfaction (P = .031) and reduced the number of postinstallation adjustments (P ≤ .001). Conclusions: A reduction in the incidence of ulcers and number of adjustments and improvement in patient satisfaction could be observed with the use of the impression technique.

Purpose: To evaluate the marginal integrity of three inlay-retained fixed dental prosthesis (IRFDP) designs fabricated using monolithic zirconia. Materials and Methods: In total, 30 IRFDPs were fabricated using 4-YTZP monolithic zirconia and randomly divided into three groups according to the cavity design. Groups ID2 and ID1.5 received an inlay cavity preparation, which includes a proximal box and an occlusal extension with a depth of 2 mm or 1.5 mm, respectively. Group PB received a proximal box cavity preparation without an occlusal extension. The restorations were fabricated and cemented using a dual-cure resin cement (Panavia V5) and subjected to an equivalent of 5 years of aging. The specimens were evaluated under an SEM to measure marginal continuity before and after the aging process. Results: During the whole 5-year aging process, no specimens showed signs of cracking, fracture, or loss of retention in any restorations. In the SEM analysis, most marginal defects observed in the restorations were areas of microgaps at the tooth/cement interface (TC) or zirconia/cement interface (ZC), resulting in loss of adaptation. There was a significant difference between the groups after the aging process at both the TC (F = 4.762, P < .05) and ZC (F = 6.975, P < .05), with Group ID2 presenting the best performance. There was a significant difference between TC and ZC in all groups (P < .05), with ZC presenting more gaps in all groups. Conclusions: Inlay cavity designs including a proximal box and an occlusal extension exhibited better marginal stability than a proximal box without occlusal extension.

Purpose: To compare the volumetric loss of clinical crown structure in commonly encountered clinical situations for monolithic ceramic crowns, occlusal overlays, and partial-coverage onlays. Materials and Methods: Typodont teeth made with preexisting mesio-occlusodistal (MOD) preparations for mandibular first molars and maxillary first premolars were prepared with three different preparations: a full-contour monolithic zirconia crown, a lithium disilicate occlusal overlay, and mesio-occlusodistobuccal/mesio-occlusodistolingual (MODB/MODL) lithium disilicate onlays for premolars and molars. 3D-metrologic software was used to evaluate the volumetric loss of clinical crown structure for each preparation type. Subsequently, the mesiolingual cusps of mandibular molars and buccal cusps of maxillary premolars were excluded for a separate analysis to simulate patient presentation with an existing restoration and sheared-off cusp. Results: Full-coverage monolithic zirconia crowns removed 45.37 to 219.53 mm3 of the remaining clinical tooth structure, depending on the clinical scenario and tooth position, while lithium disilicate overlays removed 27.48 to 105.13 mm3 and MODB/MODL lithium disilicate onlays removed 5.48 to 47.45 mm3. In each scenario tested, MODB/MODL onlays removed significantly less clinical crown structure than overlays (P < .001); both MODB/MODL onlays and overlays removed significantly less structure than full-coverage crowns (P < .001). Conclusions: Monolithic zirconia crown restorations require significantly more removal of remaining tooth structure than lithium disilicate occlusal overlays and partial-coverage onlays for commonly occurring clinical situations requiring indirect restorations.

Purpose: To evaluate the effect of simulated gastric acid solution (SGAS) and resin cement composition on the shear bond strength (SBS) of zirconia-based materials with different levels of translucency to composite resin. Materials and Methods: A total of 40 medium-opacity (MO; 3Y-TZP) and 40 medium-translucency (MT; 4Y-PSZ) zirconia slabs were distributed into four groups according to the composition of the resin luting system (MDP free or with MDP [primer + Panavia V5]) and storage method (distilled water or SGAS [5% hydrochloric acid]). Composite resin cylinders were cemented on the zirconia surface and stored for 91 hours. SBS, failure mode, and surface characterization analyses via scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were performed. SBS data were analyzed using three-way ANOVA and Tukey tests, and failure mode was assessed using one-way ANOVA (P < .05). Results: Storage media (P = .180), resin cement (P = .110), zirconia (P = .404), and their interactions did not affect SBS values. Bond strength ranged from 21.41 to 26.11 MPa. SEM images showed that SGAS modified the surface topography of zirconia and resin cement. The presence of chlorine and silicon (wt%) were higher after SGAS storage than after water storage in both cements used, while barium was higher only for the MDP cement. There was a prevalence of mixed failures for most of the groups. Conclusions: The SBS between both types of zirconia and resin cement was not affected by SGAS, although changes in zirconia topography were observed after SGAS exposure. The presence of MDP in the cement layer had no effect on the SBS challenged by SGAS.

Purpose: To realize a systematic review with prospective meta-analysis aiming to compare the accuracy of static fully guided implant placement depending on the drill key modality (conventional drill key surgery systems vs newer keyless systems) and evaluate the impact of deviation factors. Materials and Methods: An electronic systematic search was conducted to identify prospective clinical trials matching inclusion criteria. The variables of interest were coronal global, apical, vertical, and angular deviations. The types of edentulism and surgical guide support were investigated as deviation factors. Meta-regression (mixed-effect model) was performed. Heterogeneity was assessed using Cochrane’s I. test and interpretation thresholds. Results: A total of 1,233 implants in 475 patients were analyzed (18 studies included). Coronal global deviation was significantly lower in the keyless group than in the key group (–0.36 mm; 95% CI –0.62, –0.09; P = .008). Angulation control of the keyless system was superior to that of the key system (–0.36 degrees; 95% CI –0.75, 0.02; P = .063). Nonsignificant differences were found between both groups in apical (P = .684) and vertical deviations (P = .958). Significant influence of the type of edentulism (single, partial, total) and surgical guide support (tooth, mucosa, bone) on the overall amount of coronal global, apical, and angular deviations was found (P < .001). The lowest deviations were found in partial edentulism and tooth-supported surgical guide groups. (P < .001). Conclusions: Keyless static fully guided surgical systems allowed significantly better control of coronal and angular deviations than conventional systems. The types of edentulism and surgical guide support seemed to influence the positioning accuracy.

Purpose: To evaluate whether complete dentures (CDs) relined with long-term resilient liners (LTRLs) favor better masticatory function, satisfaction, and quality of life among completely edentulous patients compared to conventional CDs. Materials and Methods: This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist and was registered in PROSPERO (the International Prospective Register of Systematic Reviews; CRD42021258700). The population, intervention, comparison, and outcome (PICO) purpose was to determine whether CDs relined with LTRLs favor better masticatory function, satisfaction, and quality of life among completely edentulous patients when compared to CDs. Searches were performed in the PubMed/MEDLINE, Embase, Scopus, Lilacs, BBO, and OpenGrey databases. Manual searches were also performed to identify additional primary studies. Results: Overall, 3,953 articles were found. After removing duplicates, reading the articles, and applying the inclusion and exclusion criteria, 15 articles were selected for qualitative analysis, totaling 422 patients with follow-up periods ranging from 1 week to 3 years. Among these, 8 studies assessed masticatory function using different methods, 2 assessed satisfaction, 1 assessed quality of life, and 4 assessed more than one outcome. Through qualitative analysis, LTRLs showed satisfactory results in most studies when compared to CDs in relation to masticatory function, satisfaction, and quality of life. Conclusions: LTRLs favor better masticatory function, satisfaction, and quality of life among completely edentulous patients compared to CDs.

Purpose: To compare the performance of licensed dentists and two software versions (3.5 legacy and 4.0) of an artificial intelligence (AI)-based chatbot (ChatGPT) answering the exam for the 2022 Certification in Implant Dentistry of the European Association for Osseointegration (EAO). Materials and Methods: The 50-question, multiple-choice exam of the EAO for the 2022 Certification in Implant Dentistry was obtained. Three groups were created based on the individual or program answering the exam: licensed dentists (D group) and two software versions of an artificial intelligence (AI)-based chatbot (ChatGPT)—3.5 legacy (ChatGPT-3.5 group) and the 4.0 version (ChatGPT-4.0 group). The EAO provided the results of the 2022 examinees (D group). For the ChatGPT groups, the 50 multiple-choice questions were introduced into both ChatGBT versions, and the answers were recorded. Pearson correlation matrix was used to analyze the linear relationship among the subgroups. The inter- and intraoperator reliability was calculated using Cronbach’s alpha coefficient. One-way ANOVA and Tukey post-hoc tests were used to examine the data (α = .05). Results: ChatGPT was able to pass the exam for the 2022 Certification in Implant Dentistry of the EAO. Additionally, the software version of ChatGPT impacted the score obtained. The 4.0 version not only pass the exam but also obtained a significantly higher score than the 3.5 version and licensed dentists completing the same exam. Conclusions: The AIbased chatbot tested not only passed the exam but performed better than licensed dentists.

Traditionally, metal-ceramics, metal-reinforced acrylics, and—more recently—full-contour or layered zirconia have been the materials of choice for definitive fixed implant-supported rehabilitations. Polymethyl methacrylate (PMMA) is commonly used in implant dentistry for the fabrication of implant-supported interim prostheses and as milled or 3D-printed prototypes. This article describes a novel protocol to prosthetically restore a completely edentulous patient following a digital workflow, with fixed, screw-retained, implant-supported prostheses fabricated from CAD/CAM milled PMMA, with no metal substructure. After a 2-year follow-up in terms of esthetics, phonetics, function, and biologic tissue response, the outcome remains functional and free of mechanical, biomechanical, or biologic complications. The aim of this article is to illustrate the feasibility of using milled PMMA as a viable definitive prosthetic material for the fixed implant rehabilitation of edentulous patients. Keywords: milled-PMMA, Implant-supported prostheses, long-term implant-retained restorations, CAD-CAM milled restoration

Purpose: To study the influence of tooth mobility on the accuracy of conventional impressions. Materials and Methods: In total, 10 patients with mobile anterior teeth and 10 healthy patients were treated with conventional impressions and intraoral digital impressions. The digital impression group was recorded as standard data, the mobile teeth group was recorded as the experimental group, and the healthy anterior teeth group was recorded as the control group. We imported digital impression and irreversible hydrocolloid impression files into Geomagic Wrap and marked reference points to execute N-point alignment, then we recorded the coordinates. Paired-samples t test was used to analyze whether the point coordinates of mobile teeth were statistically significant (a = .05). One-way ANOVA was used to analyze whether there was a relationship between coordinate differences and tooth mobility in the distal, coronal, and buccal directions (a = .05). Results: In the buccal and coronal directions, the difference was statistically significant between the conventional and digital impression groups. In the buccal direction, the accuracy differences of I-degree and II-degree mobile teeth were 0.149 mm and 0.401 mm, respectively. In the coronal direction, the differences were 0.128 mm and 0.233 mm, respectively. Meanwhile, ANOVA analysis showed that there was a relationship between point coordinate difference and tooth mobility in the buccal and coronal directions. Conclusions: Conventional impressions can influence the accuracy of mobile tooth impressions. Therefore, digital impressions should be adopted for mobile teeth impressions.

Purpose: To evaluate the influence of aging on the fracture load (Lf) and reliability of glass-ceramics after different etching protocols. Materials and Methods: Specimens were fabricated and divided according to the etching Ame (10% hydrofluoric acid [HF] for 20 seconds, 40 seconds, and 60 seconds). Etched surfaces were examined under microscopy. The ceramics were resin-cemented to a dentin analog material. Samples were split into two groups (n = 20 each) and tested after 24 hours (I) or stored in 37° water for 1 year (A). A compressive load (0.1 mm/minute) was applied to the samples unAl failure was detected by acoustic emission. The influence of aging on the Lf was tested by two-way ANOVA and Tukey tests (α = .05). The characteristic fracture load (L0) and Weibull modulus (m) values were calculated. Results: Lithium silicate (LS) etching for 20 seconds resulted in the highest immediate Lf, which was significantly decreased after aging (P ≤ .05). Water storage had no effect on the Lf of glass-ceramic etched for 40 and 60 seconds (P > .05). For lithium disilicate (LD), the etching time had no significant effect on the immediate or aged Lf (P > .05). The Lf was significantly reduced after aging (A) for LD (P ≤ .05). Radial cracks were the predominant failure mode. Surface topography was more regular after lower etching times for LD and after higher times for LS. Conclusions: After 1 year of water-assisted aging, the evaluated etching times had no influence on the load-bearing capacity and structural reliability of resin-bonded glass-ceramics.