The International Journal of Prosthodontics, 03/2021

Purpose: To evaluate the effects of 0.2% sodium hypochlorite, Efferdent (Prestige Consumer Healthcare), and 6.25% Ricinus communis on biofilm removal and antimicrobial action on dentures and brushes using nonimmersion or immersion protocols for the brushes. Materials and Methods: A total of 45 denture wearers were randomly assigned to a denture immersion protocol for 7 days: 0.85% saline solution for 20 minutes (control); 0.2% sodium hypochlorite for 20 minutes (SH); Efferdent for 3 minutes; or 6.25% Ricinus communis for 20 minutes (RC). The participants were also randomized to immersion (n = 23) or no immersion (n = 22) of their brushes with their dentures in the same solutions. For biofilm evaluation, the dentures were stained and photographed, and the area of the biofilm was measured using Image Tool 3.0 (University of Texas Health Science Center). To evaluate microbial load on dentures and brushes, the biofilm was collected, and the Candida spp and Streptococcus mutans colonies were counted. Results: The SH, Efferdent, and RC groups showed reduced biofilm and Candida spp on dentures regardless of the immersion protocol for the brushes. However, no difference was found in the Candida spp counts collected from the brushes immersed compared to the brushes not immersed in the solutions. The SH and Efferdent groups showed reduced S mutans on both dentures and brushes, except for in the nonimmersion subgroups. Conclusion: All solutions reduced denture biofilm and microbial load. However, immersion of brushes in the solutions did not contribute to reducing the microbial load.

Purpose: To compare oral health–related quality of life (OHRQoL) and masticatory performance (MP) in patients treated with a mandibular complete denture (CD) and immediately loaded implant-supported prostheses (ISP). Materials and Methods: Forty patients were divided into CD and ISP groups. Initially, all patients were treated with a mandibular CD. Then, 23 patients remained with a CD while 17 patients were treated with an ISP after wearing the CD for 3 months. OHRQoL was measured using the OHIP-EDENT questionnaire, and MP was evaluated by sieving. Data were recorded before treatment (T0) and after 3 months wearing the CD and ISP (T1). Results: CD treatment did not affect OHRQoL and PM; however, patients treated with an ISP presented improvement in OHRQoL (P < .001) and MP (P < .001) with a high effect size (ES) (Cohen’s d = 2.49 and 2.47, respectively). For intergroup analysis, ISP treatment presented improvement in OHRQoL and MP compared to CD treatment (P < 0.001) at T1 with a high ES (Cohen’s d = 1.80 and 3.29, respectively). The correlation between MP and OHRQoL was positive only for psychologic discomfort in the CD group at T0 (P = .035), suggesting that poor MP increased psychologic discomfort. Conclusion: Converting a CD into an ISP had a positive impact on OHRQoL and MP with high ES.

Purpose: To evaluate the performance of complete dentures (CDs) with anatomical and nonanatomical teeth in totally edentulous elderly individuals regarding oral health–related quality of life (OHRQoL), satisfaction, masticatory performance (MP), need for adjustment after CD placement, and patient preference for occlusal type. Materials and Methods: A randomized crossover clinical trial comprising 50 edentulous elderly individuals was conducted. The participants were divided into two groups: AT-NT (rehabilitated initially with anatomical teeth and 3 months later with nonanatomical teeth) and NT-AT (rehabilitated initially with nonanatomical teeth and 3 months later with anatomical teeth). OHRQoL was analyzed using the OHIP-EDENT; a satisfaction questionnaire was applied; MP was evaluated by the median particle size (X50) after chewing an artificial test food; and the number of adjustments of the prosthesis base was assessed quantitatively. Results: Overall, 34 elderly individuals (mean age: 69 years) were analyzed. No significant difference was observed between CD users with anatomical and nonanatomical teeth for OHRQoL (P = .674), satisfaction (P = .725), MP (P = .849), or number of adjustments (P = .135). Most subjects (52.9%) did not express a preference for any occlusal surface type. However, among those with a preference, the majority (32.4%) opted for nonanatomical teeth. Conclusion: Both posterior tooth types are eligible for oral rehabilitation in elderly users of conventional CDs, as the variables were not influenced by occlusal morphology. However, further studies are warranted in highly resorbed mandibular edges or in cases of adaptation difficulties, as the results may differ.

Purpose: To report changes in denture satisfaction and oral health-related quality of life (OHRQoL) in edentulous patients treated with two-implant mandibular overdentures (IODs) over a follow-up of 8 to 10 years. Materials and methods: This is a follow-up of a previous study carried out between 1997 and 2005. The patients were originally randomly divided into one group receiving IODs and another group who had their conventional mandibular dentures relined (RCD group). The RCD group was offered and received IODs at the 2-year follow-up. The participants completed a self-administered questionnaire containing demographics, 15 variables related to denture satisfaction, and 20 questions from the Oral Health Impact Profile (OHIP-20). Changes over time were analyzed using multilevel linear models for denture satisfaction and multilevel ordinal regression analyses for OHIP-20 variables. Comparisons between groups were analyzed using Mann-Whitney U test for ordinal and t test for metric data. Results: Disregarding patients who passed away during follow-up, the 29 responders represented a response rate of 76%. The degree of denture satisfaction and the OHIP-20 scores remained high and stable in the IOD group over the 10-year observation period for all but one variable. The same factors showed only a modest improvement in the RCD group for the first 2 years; however, during the subsequent 8 years of the observation period (after receiving IODs), denture satisfaction and OHIP-20 scores improved to the same level as the original IOD group. Conclusion: The positive effect on denture satisfaction and OHRQoL of edentulous patients treated with two-implant mandibular overdentures remained unchanged 8 to 10 years after treatment.

Purpose: To assess the short-term outcomes of two different conservative preparation designs for posterior zirconia inlay-retained fixed dental prostheses (IRFDPs) and to analyze the marginal integrity of such restorations. Materials and methods: Thirty patients with a missing maxillary first molar participated in this study and were divided randomly into two groups: one that received abutment preparations for inlay retainers (ID group, n = 20), including a proximal box and an occlusal extension, and one that received only proximal box preparations (PB group, n = 10). Zirconia IRFDPs were bonded in position and followed up after 2 weeks, 6 months, 1 year, and then annually. The in situ restorations were duplicated utilizing a single-step putty/wash impression technique at the 2-week and 2-year follow-up visits. Restoration margins were evaluated under scanning electron microscopy, and marginal continuity was calculated as a percentage of the whole margin at the tooth-cement (TC) interface and the zirconia-cement (ZC) interface. Results: After a mean observation period of 26.2 months, all restorations were still in function. The only complication encountered was debonding of restorations; however, they were re-bonded back in place without issue. The cumulative Kaplan-Meier 2-year survival rate for the IRFDPs was 86.6%. There was a significant difference between the two groups regarding percentage of continuous margins (P < .05) after 2 years, with the percentage of continuous margins in the ID group at 92.8% and 91.5% at the TC and ZC interfaces, respectively, and in the PB group at 84.1% and 78.6% at the TC and ZC interfaces, respectively. Conclusion: Zirconia-based monolithic IRFDPs can be recommended for short-term replacement of a single maxillary molar.

Purpose: To find proper ceramic thickness-cement combinations for color matching of high-translucency monolithic zirconia restorations. Materials and methods: A total of 300 A2-shade high-translucency zirconia disk specimens of six different thicknesses (0.7, 0.9, 1.1, 1.4, 1.6, and 1.8 mm) were cemented to A3.5-shade composite resin backgrounds with five different cements: Temp-Bond, Zinc Phosphate, RelyX Unicem 2, PANAVIA SA Cement Plus, and GC Gold Label 1. Color measurements were conducted before and after cementation to determine the specimens' CIE L*a*b* values. ΔE₀₀ values were calculated for specimens to assess color differences between before cementation and after cementation (ΔE₁), between the A2 VITA classical shade (target) and specimens before cementation (ΔE₂), and between the target and specimens after cementation (ΔE₃). The ΔE₃ values were compared with an acceptability threshold (ΔE₀₀ = 1.8) to evaluate color matches. Data were analyzed using two-way analysis of variance, Bonferroni, and one-sample t tests (P < .05). Results: Mean ΔE₃ values ranged between 1.0 and 3.4. Ceramic thickness, cement type, and their interaction affected the ΔE₃ (P < .001). Temp-Bond with ceramic thickness of ≥ 1.1 mm and Zinc Phosphate with ceramic thickness of ≥ 0.9 showed color matches, but RelyX, PANAVIA SA, and GC did not show color matches with any tested ceramic thickness. Conclusion: Opaque cements with sufficient ceramic thicknesses created color matches for high-translucency monolithic zirconia restorations on A3.5-shade backgrounds.

Purpose: To evaluate and compare the internal and marginal adaptations of chairside CAD/CAM (CEREC) endocrowns and crowns fabricated from lithium disilicate glass-ceramic (IPS e.max CAD), zirconia-reinforced lithium silicate glass-ceramic (VITA Suprinity), and hybrid ceramic (VITA Enamic). Materials and methods: Dental models of the two first maxillary molars were selected. One was prepared for an endocrown, and the other for a standard all-ceramic crown. A total of 72 CAD/CAM restorations, including 36 endocrowns and 36 crowns made of IPS e.max CAD, VITA Suprinity, and VITA Enamic (n = 12 each), were fabricated. Discrepancies were measured in the buccal, mesial, lingual, and distal aspects of three sites (marginal, mid-axial wall, and occlusal/floor) using the noncontact ATOS scanner. Statistical analysis was performed using MANOVA and between-subject effects tests (α = .05). Results: Mesial axial wall discrepancy was significantly lower in endocrowns compared to occlusal discrepancy in crowns, while distal axial wall discrepancy was significantly higher. Moreover, floor discrepancy was found to be significantly lower in endocrowns compared to crowns. However, type of material had no significant effect on any kind of discrepancy. Conclusion: The marginal and internal adaptation values were within a clinically acceptable range for both kinds of restoration and all three materials. However, restoration type (crown vs endocrown) was significantly different in the mesial and distal axial wall and occlusal/floor discrepancies, regardless of restoration material.

Purpose: To evaluate the effect of three two-retainer designs of a resin-bonded fixed dental prosthesis (RBFDP) on fracture resistance. Materials and methods: A total of 21 three-unit, all-ceramic RBFPDs were fabricated to replace a missing maxillary lateral incisor. The prostheses were divided into three groups of 7 each: Group L (labial RBFPD); Group ML (modified labial RBFPD, fabricated the same as in Group L with additional preparation that included a shallow proximal groove at the pontic side); and Group P, an all-ceramic palatal RBFPD that acted as control. Preparations were done on the maxillary left central incisor and canine of a typodont model, and 21 epoxy resin models were duplicated for the three groups. The RBFPDs were designed using CAD software and constructed using the heat-pressed technique, after which the prostheses were bonded to their corresponding epoxy resin model according to the manufacturer's instructions. A fracture resistance test was performed on all specimens following aging. Data were analyzed using one-way ANOVA. Results: The highest fracture load values were recorded in Group P (547.5 N), followed by Group ML (462.6 N) and then Group L (418.3 N). The difference among the three designs was not statistically significant (F = 2.5, P = 0.1). Conclusion: Both labial and modified labial RBFDPs could be a viable alternative treatment option for replacement of missing maxillary lateral incisors.

Purpose: The aim of this study was to compare the microtensile bond strength (μTBS) of different CAD/CAM polymer-based ceramics to a repair composite resin using various bonding protocols. Materials and Methods: Three different CAD/CAM polymer-based ceramics (LAVA Ultimate [LU], 3M ESPE; VITA Enamic [VE], VITA Zahnfabrik; and CeraSmart [CS], GC) were used. Ceramic slices were obtained and subjected to thermal cycling between 5°C and 55°C for 5,000 cycles with a 30-second dwell time. The samples were randomly separated into the following groups: universal adhesive (UB); hydrofluoric acid (HF); sandblasting (SN); HF + UB; HF + ceramic primer (PR) + adhesive (GB); SN + UB; and SN + PR + GB. The repair composite resin (G-aenial Universal Flo, GC) was applied to the samples and subjected to re-aging between 5°C and 55°C for an additional 5,000 cycles. Parallel sections were removed from the specimens, and multiple beamshaped micro sticks (1.0 mm × 1.0 mm × 10 mm) were prepared for each group. Subsequently, the μTBS test was performed, and the obtained data were statistically analyzed via one- and two-way analysis of variance and Tukey post hoc tests. Scanning electron microscopy (SEM) analysis was also performed. Results: Significant differences were found among the experimental groups (P < .05). The μTBS values of the UB bond groups were higher than those with the GB bond. The effect of pretreatment on μTBS (ηP 2 = 0.556) was more significant than ceramic type (ηP 2 = 0.481), and this result was supported by the SEM images. Conclusion: Pretreatment before application of universal adhesive is still needed to repair hybrid ceramic restorations with composite resins.

Purpose: To test whether internal accuracy affects the load-bearing capacity of 0.5-mm-thick occlusal veneers made out of milled or heat-pressed lithium disilicate (LS2). Materials and methods: Extracted human molars (N = 80) were divided into four groups (n = 20 each) depending on the bonding substrate (enamel [E] or dentin [D]) and the fabrication method (milling [CAD] or heat pressing [PRE]) for the occlusal LS2 veneers: (1) E-CAD, (2) D-CAD, (3) E-PRE, or (4) D-PRE. After restoration fabrication, the abutment teeth and the corresponding restorations were scanned and superimposed in order to measure the marginal and internal accuracy. After adhesive cementation, the specimens were thermomechanically aged and thereafter loaded until fracture. The load-bearing capacities (F_max) were measured. F_max and the marginal and internal accuracy between the groups were compared using Kruskal-Wallis test (P < .05) and pairwise group comparisons. In addition, the relationship between F_max and the internal accuracy was analyzed using Spearman rank correlation. Results: Median F_max values (and first and third quartiles) per group were as follows: 1,495 N (Q1: 932; Q3: 2'318) for E-CAD; 1,575 N (Q1: 1,314; Q3: 1,668) for E-PRE; 1,856 N (Q1: 1,555; Q3: 2,013) for D-CAD; and 1,877 N (Q1: 1,566; Q3: 2,131) for D-PRE. No statistical difference was found between the groups (P = .0981). Overall, the internal accuracy in the areas of the cusp (P < .0007) and fossa (P < .0001) showed significant differences. While no significant differences were detected in the marginal area (P = .3518), a significant correlation with a negative linear relationship was found between the 3D internal accuracy and the F_max values (P = .0007). Conclusion: An increase in the internal accuracy raised the load-bearing capacity of minimally invasive LS2 occlusal veneers. In general, the restorations bonded to dentin in the occlusal regions showed a better accuracy compared to those bonded to enamel.

Purpose: (1) To present a Danish quality register (AMETO) concerning dental implant treatment for dental agenesis, assess its indicators and standards, and compare them with those acknowledged and outlined by the Institute of Medicine (IoM), World Health Organization (WHO), and Organization for Economic Cooperation and Development (OECD), classified as the quality domains efficiency, effectiveness, patient-centered care, timely care, safety, and equitability; and (2) to perform a systematic literature search and review to verify whether any quality register exists according to the six quality domains. Materials and methods: (1) The AMETO register is comprised of 16 process and result indicators and standards, which were compared to the six quality domains outlined by the IoM and WHO. (2) A systematic literature search was carried out using the search engines PubMed, Embase, CINAHL, Web of Science, and SveMed+. The included articles were assessed for quality indicators and standards to determine whether they conformed to the six quality domains. Results: AMETO indicators and standards conformed to the quality domains outlined by the IoM. A search of "(dental agenesis) AND (dental implants)" yielded a total of 381 publications, of which 27 were included for qualitative synthesis. A search on quality indicators and dental agenesis registries yielded no results. Due to considerable heterogeneity in the reported quality indicators related to effectiveness, patient-centered care, and safety, a meta-analysis could not be conducted. Conclusion: AMETO conforms to the quality domains described by the IoM, WHO, and OECD. Few studies have investigated dental implant treatment of dental agenesis. Moreover, no published quality register for dental implant treatment currently exists.

Purpose: To evaluate the marginal and internal adaptation of all-ceramic crowns and inlays fabricated by different scanners of the same CAD/CAM system. Materials and methods: All-ceramic crown preparations were performed on typodont maxillary first premolars, and mandibular first molars were prepared for ceramic Class II mesio-occlusal inlays. Two intraoral scanners (CEREC Bluecam and Omnicam, Dentsply Sirona) and one model scanner (CEREC inEos X5, Dentsply Sirona) were used to scan the preparations. All restorations were fabricated by milling single-feldspathic ceramic blocks (CEREC Blocks). The marginal and internal discrepancies of restorations were evaluated via micro-CT analyses. Results: For linear crown measurements, the marginal gaps were 63.75 μm, 88.24 μm, and 90.89 μm for Bluecam, Omnicam, and inEos X5, respectively. For crowns at central groove areas, the maximum values for Bluecam, Omnicam, and inEos X5 were found to be 144.78 μm, 165.19 μm, and 129.49 μm, respectively. For inlays, the highest range at the midpoint of the axiopulpal line angle for Bluecam, Omnicam, and inEos X5 were determined as 138.57 μm, 184.33 μm, and 179.71 μm, respectively. In volumetric measurements, inEos X5 showed lower gap for both crowns (11.47 mm³) and inlays (5.65 mm³) compared to both intraoral scanners. These results are within a clinically acceptable range. Conclusion: When all-ceramic crowns were evaluated, there were generally no significant differences found between scanners for the regional linear measurements, but more gaps occurred in restorations obtained with intraoral scanners for volumetric measurements. On the other hand, when the inlay restorations were evaluated, significant differences were found between groups except for the midpoint of the axio-pulpal line angle and the midpoint of the mesio-gingival margin. However, marginal and internal gaps of both crowns and inlays presented mean values less than 150 μm in many surfaces, which could be considered clinically acceptable.

Purpose: To evaluate the accuracy of superimposition of customized abutment library data onto scanned abutment data according to the extent of the scanning area. Materials and methods: A patient model was fabricated by a 3D printer (Probo, DIO Implant), and a customized abutment was fabricated using a four-axis milling machine (ARUM 4X-100, Doowon). The customized abutment library data were generated using a laboratory scanner (E3, 3Shape) for superimposition after intraoral scanning. A cone-shaped structure was embedded into the library data at the center of the connection part. The customized abutment was placed on the model, and the model was scanned using a laboratory scanner to produce reference data. Three different test group datasets were generated using intraoral scanner and computer-aided design software: (1) fully scanned customized abutment; (2) insufficiently scanned proximal surface; and (3) insufficiently scanned margin, assuming challenging intraoral conditions. The library data were superimposed onto each test group; thereafter, the distance and angle between the reference and test group data were analyzed by using the embedded cone. Statistical analysis was performed using one-way analysis of variance followed by post hoc Tukey test for multiple comparisons. Results: There were no statistically significant differences between the mean distance and angle of the test group data (with three different scanning areas) and the reference data. Conclusion: The superimposition technique can be used clinically, not only when the scan is complete, but also when the proximal surface and margin of the customized abutment have been scanned incompletely.

This is a case report of a patient with soft palate muscle weakness that caused difficulties with phonation. A provisional palatal lift prosthesis (PLP) was developed, and the patient underwent simultaneous speech therapy. The elevation level of the palatal lift was subjectively assessed along with nasalance analysis and the Urimal Test of Articulation and Phonation results. The final PLP was applied to improve comfort and efficiency, and the patient continually underwent regular speech therapy. The patient showed satisfactory improvement in speech and pronunciation. PLP development combined with speech therapy can improve the accuracy of pronunciation in patients with palatal incompetence, thereby improving quality of life.