The International Journal of Prosthodontics, 05/2023

In this position paper, the state of the art in immediate implant placement (IIP) at incisor-cuspid-premolar sites is described. The literature supports that the following prerequisites need to be simultaneously met for a predictable outcome: (1) there must be no acute infection; (2) there must be apical and palatal/lingual bone for implant anchorage; (3) the tooth must be inside the bone envelope; (4) the alveolar socket must have a favorable morphology (type I, IIa, IIb avoiding wide dehiscences); (5) there must be no midfacial recession; (6) the right implant must be selected; and (7) the surgeon needs to be experienced and skilled. A preoperative CBCT is required for IIP because multiple aforementioned prerequisites (2, 3, and 4) can only be assessed on the basis of 3D imaging. The final prerequisite relates to the importance of a perfect implant position, preferably leaving a horizontal gap of at least 2 mm between the implant shoulder and buccal bone wall. Guided surgery is preferred over free-hand surgery to accomplish this. Flapless surgery, socket grafting, connective tissue graft (CTG), and immediate provisionalization have been shown to contribute to hard and/or soft tissue stability. When the previously mentioned prerequisites are fulfilled, IIP may be considered over alternative treatment concepts (eg, early implant placement [EIP] and delayed implant placement [DIP]) based on time gain, minimal invasiveness, and similar outcomes in the literature. Given very strict selection criteria, clinicians should primarily screen patients for IIP before considering other treatment options with wider indications. Int J Prosthodont 2023;36:533–545.

Purpose: To assess and compare the clinical outcomes of three different types of all-ceramic posterior monolithic tooth-supported crowns. Materials and Methods: A total of 71 patients received 90 all-ceramic crowns randomized to be either high-translucency zirconia (ZC), high-translucency zirconia with a partial buccal veneer (ZC-V), or lithium disilicate glass-ceramic (LDS). All treatments were performed by four general dentists who were blinded to the material used. Baseline and subsequent annual evaluations were based on modified California Dental Association (CDA) criteria. A questionnaire was used to include patient-reported outcomes and to compare them to the crown quality rating performed by dentists. Results: A total of 66 patients with 84 crowns were examined after 3 years. The survival rate was 98.8%. No crowns fractured during the observation period. One ZC-V crown failed due to loss of retention, and three complications were noted: loss of retention occurred in one ZC crown, and two ZC crowns needed to be endodontically treated. There was no significant difference between the different crowns regarding marginal integrity, surface, or anatomical form. Both patients and examining dentists rated the crowns favorably regarding esthetics, patients more than dentists. Conclusions: All crown types used show excellent and promising clinical outcomes from a short-term perspective. Patients and dentists rate the restorations favorably concerning esthetics and function. Int J Prosthodont 2023;36:546–553.

Purpose: To assess oral health–related quality of life (OHRQoL) and patient satisfaction with a three-implant-retained mandibular overdenture. Materials and Methods: In this randomized crossover clinical trial, 20 edentulous patients received a new set of conventional complete dentures (CDs; baseline). Subsequently, three implants were placed in the anterior mandible: two were placed in the canine regions bilaterally and one in the midline. After successful osseointegration, CDs were attached to the implants using resilient attachments. The overdenture was retained either by three implants (test group) or two implants (control group). The sequence of treatment was randomized such that each patient experienced both treatment options for 6 months each. OHRQoL was assessed at baseline and after 6 months of function for each treatment option using the Oral Health Impact Profile (OHIP-14) and visual analog scale (VAS) scores. Statistical analyses were performed using Friedman and Wilcoxon signed rank tests. Results: CD resulted in significantly higher OHIP-14 and VAS scores (25.25 + 6.42, 8.55 + 1.73) compared to both the control group (11.15 + 5.39, 4 + 2; P < .001) and the test group (6.25 + 4.02, 2.06 + 1.48; P < .001). Similarly, significantly higher mean OHIP-14 and VAS scores were noted for the control group compared to the test group (P < .001). Conclusions: Overdentures retained by three implants resulted in better OHRQoL scores and higher patient satisfaction compared to overdentures retained by two implants and CDs. Int J Prosthodont 2023;36:554–56

Purpose: To evaluate and compare the changes in brain activity for individuals with a single missing mandibular molar replaced with a removable dental prosthesis (RPD) and a fixed tooth-supported implant prosthesis in the static and postmasticatory phases. Materials and Methods: In total, 24 patients with a unilateral missing mandibular first molar were rehabilitated with a removable dental prosthesis and divided into two groups of 12 each; Group A was rehabilitated with implants and Group B with 3-unit tooth-supported fixed partial dentures (FPDs). An electroencephalogram (EEG) was taken during the three phases of assessment: (1) before insertion of any prosthesis (N0), (2) after insertion of an RPD (N1), and (3) after cementation of an FPD or implant crown (F2). The effect of bite force with RPD (N1M) and FPD or implant prosthesis (F2M) on alpha waves was evaluated by recording EEG immediately after chewing gum for 30 seconds. Results: The improvement of the amplitude of alpha waves before and after prosthesis insertion showed a significant difference between Group As and B (P < .05) with the highest mean values of 158.3 µV, 147.9 µV, and 182.1 µV occurring in pairs F2-N0, F2-N1, and F2M-N1M, respectively, for Group A. Similarly, for the power of alpha waves between group A and B, a statistically significant difference (P < .05) with the highest mean values of 30.3 dB, 28.9 dB, 36.9 dB, and 11.2 dB in pairs F2-N0, F2-N1, F2M-N1M, and F2M-F2 ,respectively, was observed for Group A. There was no statistically significant increase in pair N0-N1 (P > .05). Conclusions: Replacement of a single missing tooth enhanced brain activity and was highest with an implant-supported crown. Int J Prosthodont 2023;36:563–569.

Purpose: To report the results of a 2020 international survey of the most commonly used materials and techniques for the fabrication of extraoral maxillofacial prosthetics, and to assess the use of 3D technology. Materials and Methods: A 43-question survey was administered via Qualtrics to the members of the American Academy of Maxillofacial Prosthetics (AAMP), the International Anaplastology Association (IAA), and the International Society of Maxillofacial Rehabilitation (ISMR). The use of current 3D technology in the fabrication of maxillofacial prostheses as well as barriers to care such as patient cost and insurance coverage were also assessed. Results: In total, 134 respondents (13%) completed the survey; 96 (73%) reported that they were currently fabricating maxillofacial prostheses and were thus included in the survey. The majority of respondents reported currently using Silastic MDX4-4210 BioMedical Grade Elastomer (DuPont) with either Silastic Medical Adhesive Silicone Type A or Silastic MDX4-4210 crosslinker. Incorporating the use of current CAD/CAM technology was reported by a majority of respondents (58%; 45/77); however, a small cohort (33%, 15/45) reported they were still experimenting how best to use technology. A total of 39 clinicians (49%) reported that facial prosthetics were most often paid for by the patient (fee for service), with the fees ranging from $10 to $5,500 USD. Conclusions: The results of this survey indicate that current CAD/CAM technology has been adopted and incorporated into the design and fabrication of maxillofacial prostheses. More research is needed to advance CAD/CAM technology as well as the physical and mechanical properties of materials in maxillofacial prosthetics and anaplastology clinical practice. Int J Prosthodont 2023;36:570–580.

Purpose: To compare the adaptation of single metal-ceramic crowns (MCCs) fabricated with three different methods: lost-wax metal casting (LMC), milling of hard cobalt-chromium (HCC) blanks, and milling of soft presintered cobalt-chromium (SCC) blanks. Materials and Methods: In this double-blind parallel randomized clinical trial, 60 single MCCs were fabricated using three different methods. Adaptation of the copings was evaluated radiographically, visually, and microscopically. Data were compared among the three groups using the Kruskal-Wallis test, followed by the Dunn post hoc test, one-way ANOVA, and paired t test (α = .05). Results: Radiographic data showed that the frequency of crowns with no marginal discrepancy was significantly higher in the SCC group than the LMC group. Evaluation of marginal adaptation with an explorer revealed that crowns with excellent marginal adaptation had lower frequency in the LMC group than the HCC and SCC groups. In the silicone replica technique, the recorded data revealed no significant difference. Application of porcelain veneering did not affect the adaptation of the copings. Conclusions: The SCC and HCC groups showed better clinical outcomes compared to the LMC group. However, all MCCs fabricated with the LMC method, milling of HCC blanks, and milling of SCC blanks had acceptable clinical adaptation. Int J Prosthodont 2023;36:581–587.

Purpose: To evaluate the efficacy of cleaning protocols for the decontamination of organic compounds from polished zirconium oxide samples. Materials and Methods: A total of 24 rectangular plate specimens were sintered from zirconium oxide. All samples were polished with commercially available polishers (coarse, fine, and superfine) and polishing paste. During the first step of the protocol, all specimens were cleaned with steam. Samples were then randomly assigned to one of three groups (n = 8 each): A, B, or C. In group A, no additional cleaning was performed, while specimens in group B underwent ultrasonic cleaning in distilled water. Group C specimens were cleaned in an ultrasonic bath with a special detergent solution. After washing, samples were subjected to energy-dispersive x-ray spectroscopy (EDX) and scanning electron microscopy (SEM) examination. In order to detect organic materials, the level of carbon atoms was measured. Results: EDX analysis revealed that samples in group A had the highest percent of carbon atoms (9.57 ± 3.67) on the surface compared to other cleaning protocols. Following the Group B cleaning protocol resulted in lower carbon levels (4.73 ± 3.56), but this difference was not significant compared to group A (P = .439). None of the specimens in group C had detectable carbon atoms (0), which implies that all wax molecules were removed (P < .05). Conclusion: Total decontamination of organic compounds from a polished zirconium surface can be expected only following the C cleaning protocol; therefore, it is advised to employ an ultrasonic bath with detergent solution for cleaning procedures of zirconium abutments before delivery. Int J Prosthodont 2023;36:588–594.

Purpose: To evaluate the effect of three different curing protocols based on different ratios of self-curing and light-curing periods on the bond strength and nanoleakage of fiber posts luted with dual-curing self-adhesive cements. Materials and Methods: A total of 48 single-root teeth were endodontically treated and obturated, and an 8-mm post space was prepared with dedicated drills. Specimens were randomly divided into two groups according to the self-adhesive cement employed: group 1 (G1) = PANAVIA SA Plus (Kuraray Noritake), and group 2 (G2) = Bifix SE (VOCO). The specimens were further divided into three subgroups  (n = 8 each) according to the light-curing protocol applied: no light-curing (SG1), 20 seconds of light-curing 20 seconds after cement injection (SG2), and 20 seconds of light-curing 120 seconds after cement injection (SG3). Slices of 1-mm thickness were prepared for the pushout test and nanoleakage analyses of the coronal and apical regions after 24 hours of storage in artificial saliva. Results were statistically analyzed with three-way ANOVA and Tukey post hoc tests. Statistical significance was set for P < .05. Results: Three-way ANOVA analysis showed that the factors of cement (P = .02) and curing protocol (P < .001) had a significant influence on bond strength. Tukey post hoc test reported that light-curing 120 seconds after injection showed higher bond strength compared to both no light-curing and photoactivation after 20 seconds. Conclusion: To achieve the highest bond strength with self-adhesive cements, photoactivation with a 120-second delay after mixing is required. There is no difference between light-curing immediately and light-curing 20 seconds after mixing. 

Purpose: To evaluate the fracture strength of endodontically treated molars filled with different composite resins with vs without fiber reinforcement. Materials and Methods: A total of 60 intact mandibular molars were selected and endodontically treated. A standardized mesio-occlusal-distal cavity was prepared with cervical margins 1 mm above the cementoenamel junction and oral and buccal walls with 1.5-mm thickness. Universal adhesive was used in all specimens in etch-and-rinse mode. Specimens were divided into four groups (n = 15 each) according to restoration technique: group CSM = adhesive overlay with hybrid ceramic; group EXP = direct restoration with short fiber–reinforced composite; group ESU = direct restoration with nanohybrid composite; and group EST = direct restoration with nanohybrid composite reinforced with horizontal bidirectional glass fibers placed over the pulpal chamber floor. After 7 days of storage in water, samples were loaded until fracture using a universal testing machine. The maximum breaking loads were recorded in Newtons, and statistical analysis was then conducted with two-way ANOVA and post hoc Tukey test. Fragments were analyzed using scanning electron microscopy. Results: Mean fracture resistance values were: CSM = 1,428.91 ± 316.90 N; EXP = 1,874.57 ± 299.47 N; ESU = 1,557.44 ± 355.65 N; and EST = 1,870.27 ± 145.11 N. The CSM and EXP groups showed the highest strength values when compared to the other groups. The variable fiber insertion did not significantly alter the fracture resistance. The origin of the fracture was always located on the occlusal surface, mainly in the major contact loading area. Conclusion: The use of fiber-reinforced composite showed great improvement in fracture resistance, similar to a cuspal coverage restoration. However, only short fiber–reinforced composites showed a favorable fracture pattern. Int J Prosthodont 2023;36:603–611

Purpose: To investigate the physical and mechanical behaviors of polyether ether ketone (PEEK) before and after thermocycling, as well as its potential use as a more durable prosthetic component for implant-supported and -retained removable dental prostheses (I-RDPs). Materials and Methods: Roughness and surface hardness were evaluated in specimens obtained using the subtractive method (n = 20) with a diameter of 9 mm and a thickness of 2 mm, and retention force was measured using attachments with a diameter of 4 mm and a height of 3 mm. For fatigue resistance testing, a polyurethane matrix with two ball abutment implants (MDL, Intra-Lock International) was used to simulate the mandibular alveolar ridge. A total of 40 attachments (n = 20 pairs) were placed in acrylic resin blocks using an analog technique for the direct clinical pickup of overdenture female attachments, then submitted to 2,900 insertion/removal cycles to simulate 24 months of overdenture use. Physical analyses were performed by Fourier-transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), and differential scanning calorimetry (DSC) before and after thermocycling (5°C to 55°C for 10,000 cycles). After normal distribution was verified by Shapiro-Wilk test, one-way ANOVA was applied to analyze the surface roughness and hardness, and two-way ANOVA with Bonferroni adjustment was used to assess the retention force (α = .05). Results: Thermocycling did not change the PEEK surface roughness or hardness (P > .05). As for the retention force, the highest average was observed after the thermocycling test (P = .006). Conclusion: Based on the FTIR, XRD, and DSC results, PEEK crystallinity decreased after thermocycling, and the physical and mechanical behaviors of this polymer were compatible with the proposed application, suggesting that PEEK is a component of greater durability for I-RDPs. Int J Prosthodont 2023;36:612–619.

Purpose: To verify the parameters and characteristics evaluated in 3D-printed complete denture (CD) bases and how they influence CD properties. Materials and Methods: This work was registered in Open Science Framework (osf.io/4um6v) and followed the PRISMA Extension for Scoping Reviews. A search of peer-reviewed articles published up to April 9, 2020, was performed on the PubMed, LILACS, Cochrane Library, and Science Direct databases. The review question based on the PCC (population, concept, and context) was: What printing parameters and characteristics of CD bases can influence their properties? Results: The database search resulted in 1,945 articles, and the initial screening was carried out in 1,390 articles, 17 of which were selected for inclusion in this review. The present authors verified that cleaning the prosthesis with alcohol after printing followed by a postcuring cycle influences biocompatibility and residual monomers. The printing angle influences physicomechanical properties, microbial adhesion, and tissue adaptation. Accuracy is influenced by layer thickness and manufacturing technique, which also influences retention and tissue adaptation. The incorporation of antimicrobial agents influences physicomechanical properties and antimicrobial activity. The method of union between the denture base and teeth influences mechanical strength. Conclusions: Printed denture bases showed good adaptation to tissues and accuracy with 100-µm layer thickness, but the base must be cleaned in ethanol followed by postcuring for better biocompatibility. Nano- and microparticles can be added to provide antimicrobial activity and better resistance. The printing angle and mechanical properties must be better evaluated. Int J Prosthodont 2023;36:620–629.

Purpose: To compare characteristics of temporomandibular disorders (TMDs) in patients with rheumatoid arthritis (RA) to patients without RA. Materials and Methods: The sample included 80 patients (aged 33 to 73 years; 88% women and 22% men) with 40 in each group. An international diagnostic protocol for TMDs was followed. Results: Arthralgia was the most prevalent TMD in the RA group. Orofacial pain was more common in the RA group than in the controls (42.5% vs 15%, P = .031), with higher chronic pain grade and pain intensity (P ≤ .005). Somatization and depression were also increased (P < .001). In multiple logistic regression analysis, arthralgia (OR: 6.4; 95% CI: 1.1 to 37.1; P = .038) and age ≥ 55 years were predictors of RA (OR: 3.9; 95% CI: 1.4 to 10.8; P = .009) when controlling for the effects of biological sex and pain intensity. TMDs were related to 7.4 times higher odds for presence of orofacial pain, while RA was related to 3.4 times higher odds for pain. Conclusions: RA patients experienced more orofacial pain and higher pain intensity, somatization, and depression compared to healthy individuals. Pain is more influenced by TMDs than by RA. Int J Prosthodont 2023;36:630–636.

A technique for the virtual design of a three-piece stackable auricular mold for unilateral auricular defect rehabilitation using an open-source software program is described. An optical intraoral scanner is used to scan the patient’s ear on both the affected and unaffected side. To maintain the relationship between the mold parts, a stackable attachment is designed and joined to the mold. The mold is 3D printed in resin. This technique provides the patient with a precise auricular prosthesis with perfect thickness, adaptation, and appearance. The workflow introduced in this technique could be considered as an alternative way to fabricate auricular prostheses in a much shorter clinical and laboratory time compared to the conventional workflow. Int J Prosthodont 2023;36:637–641.

Albers-Schönberg disease is a rare bone syndrome characterized by increased bone density and infectious complications after dental extraction or minor surgery. The prosthodontic management of such edentulous patients with osteomyelitis is very challenging and requires special strategies due to a high risk of failure and worsening of the condition. This clinical report describes the rehabilitation of a 31-year-old edentulous woman presenting with Albers-Schönberg disease, secondary chronic osteomyelitis, maxillary hypoplasia, compromised oral conditions, temporomandibular disorders, and psychologic distress. The treatment included a mandibulectomy and removable prostheses. A crucial element for the successful long-term treatment and quality of life improvement observed in this patient was the 1-year transitional phase with interim dentures and frequent follow-up appointments. The complications and management proposed during a 10-year follow-up are presented. Int J Prosthodont 2023;36:642–648.

Purpose: To compare the CIE L*a*b* values of two different dental shade guides using two shade-matching spectrophotometers. Materials and Methods: SpectroShade Micro (SS) and Easyshade (ES) (VITA Zahnfabrik) were tested. One calibrated operator performed 30 measurements of each tab from three batches of the two guides, VITA Classical (VC) and VITA 3D Shade Master (VM). Receiver operating characteristic (ROC) curves and intraclass coefficients (ICC) between the different batches were calculated. Results were given as mean and SD of the L*a*b* values and the respective color differences according to the CIEDE 2000 formula (ΔE00) for each of the shade tabs in the two spectrophotometers and then analyzed with independent student t test (α = .05). Results: A total of 1,440 and 2,610 measurements for VC and VM, respectively, were performed per spectrophotometer. There were statistically significant differences between the two devices for all L*a*b* values, with the exception of: L* for 3R1.5; a* for 2R1.5, 3L1.5, 2L2.5, 3M2, 3L2.5, 4L1.5, and 4L2.5; and b* for D3, 1M2, and 3M2. When assessing the same shade guide, differences in ΔE00 were detected between devices above the acceptability threshold (AT) (ΔE00 ≥ 1.8) for all shade tabs except for VC (C1, C2, D3, A3.5, C3, and A4) and VM (4M1, 3R2.5, 4L2.5, and 4M3). The overall mean of the interdevice ΔE00 was 2.2 ± 1.0 for VC and 2.5 ± 1.0 for VM. Conclusions: The two dental spectrophotometers presented high ICC and ROC values, which validates their indication as auxiliary tools. However, there are discrepancies in the hues D (VC) and R (VM) with interdevice variability when evaluated for the L*a*b* component. Int J Prosthodont 2023;36:e38–e52.

Purpose: To evaluate the fracture-behavior of monolithic crowns made of lithium disilicate (IPS e.max CAD, Ivoclar Vivadent; IniBal LiSi Block, GC Dental) and zirconia-reinforced lithium silicate (Celtra Duo, DeguDent; VITA Zahnfabrik) materials before and after cyclic fatigue aging. Materials and Methods: Four groups (n = 22/group) of CAD/CAM fabricated upper incisor crowns were produced. All crowns were luted on metal dies with an adhesive dual-cure resin cement (G-CEM LinkForce, GC Dental). Half of the crowns in each group (n = 11) were statically loaded until fracture, without aging. The remaining crowns were subjected to cyclic fatigue aging for 120,000 cycles (Fmax = 220 N) and then loaded statically until fracture. The fractured models were then visually examined. Scanning electron microsopy (SEM) and energy-dispersive spectroscopy (EDS) were used to evaluate the microstructure of CAD/CAM ceramic materials. The data were statistically analyzed with two-way ANOVA followed by the Tukey HSD test (α = .05). Results: Before cyclic aging, there was no statistically significant difference in load-bearing capacity among the four groups (P = .371). After cyclic aging, load-bearing capacity significantly decreased for all groups (P = .000). While the e.max CAD blocks had significantly higher load-bearing capacity (1061 ± 94 N) than both monolithic ceramic crowns (load-bearing capacities of the groups) (P < .05), no significant difference was obtained with the Initial LiSi Block group (920 ± 140 N) (P = .061). Conclusions: The mechanical performance of monolithic ceramic crowns fabricated from lithium disilicate was befer than zirconia-reinforced lithium silicate after cyclic fatigue aging. Int J Prosthodont 2023;36:e29–e37

Purpose: To assess if the implant-retained prostheses produced with laser-sintering technique present an accuracy and passive fit comparable to their milled counterpart. Materials and Methods: Two regular neck Straumann analogs were placed in a block of PMMA 15 mm apart and parallel to each other. The PMMA block was then scanned and two groups of cobalt-chromium, screw-retained, three-unit implant prostheses were fabricated using milling (control) and laser-sintering (test) techniques. The prostheses were then screwed on the PMMA block and the vertical marginal gap between the prostheses and the analogs at the implant-abutment junction was measured twice, (1) when only one screw was tightened, and (2) when both screws were fully tightened. The average of each marginal gap measurement was compared to assess the difference in term of passive fit between the laser-sintered and the milled prostheses. Results: The mean marginal gap of the milled and the laser-sintered groups were 23.18 µm (SD = 6.2) and 23.71 µm (SD = 19.5) respectively. Conclusions: Laser-sintered prostheses presented a marginal fit comparable to their milled counterpart and represent a clinically valid alternative to their milled counterpart. Int J Prosthodont 2023;36:e53–e60.

Purpose: To evaluate different protocols for recementation of dislodged glass fiber posts (GFPs). Materials and Methods: The root canals of 50 bovine incisors were prepared to receive GFPs that were conditioned with 24% hydrogen peroxide, silanized, and cemented with a self-adhesive resin cement. After light curing, the specimens were submitted to a pullout test. The dislodged GPFs were distributed into five experimental groups (n = 10) for the recementation surface treatment: NT = no treatment; SI = silane; ET = 92.8% ethanol/silane; HP = 24% hydrogen peroxide/silane; and AL = airborne-particle abrasion (50 μm alumina)/silane. The GFPs were recemented with the same self-adhesive resin cement, and specimens were submiLed to a second pullout test. Data were analyzed with Student t test and one-way ANOVA (α = .05). Results: For all groups, the recementation bond strength was higher than the strength obtained after the first cementa4on (P < .05). There were no statistical differences among the experimental recementation protocols (P = .096). Conclusions: All recementation protocols might be reliably applied because they led to higher bond strength than the first cementation. Int J Prosthodont 2023;36:e74–e87

Purpose: To evaluate the application of chitosan as a cleanser in the control of biofilm formation on cobalt-chromium (Co-Cr) alloy and acrylic resin surfaces. Materials and Methods: In total, 172 Co-Cr discs and 172 acrylic resin discs (14 mm x 3 mm) were contaminated with Streptococcus mutans, Staphylococcus aureus, Candida albicans, or Candida glabrata and incubated for 48 hours. Then, specimens were randomly divided into groups and immersed in the following solutions for 15 minutes: solution without chitosan (WC/control); chitosan solution (CH: 5 mg/mL); chitosan nanoparticle solu.on (CN: 3.8 mg/mL); and effervescent tablet (ET). Biofilm recovery rates (n = 9) were evaluated by counting the colony-forming units (CFU/mL). Biofilm morphology was evaluated using scanning electron microscopy (SEM). Data were compared using the Kruskal-Wallis or ANOVA tests followed by the Tukey post hoc test. Results: For acrylic resin, ET showed the lowest number of CFU for S aureus and S mutans (P < .001). CH exhibited intermediate values for S mutans, S aureus, and C albicans; CN exhibited intermediate values for S mutans and S aureus. For C glabrata, there was no sta.s.cal difference between the solu.ons (P = .264). For Co-Cr, ET showed the highest level of antimicrobial action against all microorganisms (P < .001), and CH showed an intermediate level of action against S mutans and S aureus. Against C albicans and C glabrata, there was no significant difference among CH, CN, and WC. Conclusions: Although ET had a broader spectrum of antimicrobial action, CH showed promise as a denture cleanser. Int J Prosthodont 2023;36:e61–e73.

Purpose: To assess the influence of the bonding system and restorative material on the marginal integrity and pull-off forces of monolithic all-ceramic crowns bonded to titanium base (ti-base) abutments. Materials and Methods: A total of 108 ti-bases were sandblasted and divided into nine experimental groups (n = 12) according to the combination of crown material (polymer-infiltrated ceramic-network [PI], lithium-disilicate [LD], and zirconia [ZI]) and bonding system (Multilink Hybrid-Abutment [MH], Panavia V5 [PV], RelyX Ul5mate [RU]) with the respective primers. After bonding the crowns to the ti-base abutments, the restorations were screw-retained on implants and thermomechanically aged (1,200,000 cycles, 49 N, 1.67 Hz, 5 to 55°C). Marginal integrity and bonding failures were evaluated under a light microscope, and pull-off forces (N) were calculated. Chi-square tests for marginal integrity as well as one-way and two-way ANOVA statistical tests for pull-off forces were applied (a = .05). Results: PI presented higher marginal integrity than LD (P = .023). Bonding system PV revealed higher marginal integrity than MH (P =.005) and RU (P =.029). Differences in pull-off forces were found between restorative material and resin cements (P < .001), with the highest values for ZI + RU (598 ± 192 N), PI + PV (545 ± 114 N), LD + MH (532 ± 116 N), and PI + RU (528 ± 81 N). Specimens with marginal integrity revealed higher pull-off forces than those with alteration (P = .006). Specimens presenting bonding failures (micromovements) showed lower pull-off forces than those without bonding failures (P < .001). Conclusions: The tested CAD/CAM materials show favorable bonding performances with different bonding systems, nevertheless for each restorative material a specific bonding system has to be recommended. Int J Prosthodont 2023;36:e88–e102

Purpose: To investigate the optimal combination of factors (finish line, scanning, and ceramic processing) to achieve the best values of both adaptation and fracture load for lithium disilicate crowns (LD). Materials and Methods: Two abutment preparations, chamfer (C) and rounded shoulder (S), were produced with a dentin analog material and scanned with either extraoral (E) or intraoral (I) scanners. Images were processed using CAD software to design a premolar. Blocks of LD were milled using a CAD/CAM system (CAD). For the press technique (PRE), crowns were first 3D printed using a polymeric material, then heat-pressing protocol was performed. Design of experiments was used to plan four experimental groups (n = 10): CAD-CI, CAD-SE, PRE-CE, and PRE-SI. Two dependent variables were analyzed: adaptation, measured using the replica technique; and fracture load of the cemented crowns. Fractographic analysis was performed. Data were analyzed using ANOVA and regression statistical analyses. Results: There was no significant effect of the scanning method and finish line on the gap thickness in the different regions. For the processing method, CAD resulted in larger gap thickness in the occlusal, axial angle, and marginal areas and a smaller gap in the axial area (P < .001). The investigated factors had no effect on the fracture load. Yet, PRE-CE was considered the optimum design because it achieved 100% of the desired fracture load (>1000 N) and 40% adaptation (< 200 µm). Conclusions: The optimum combination of factors for all-ceramic crowns is chamfer abutment preparation, extraoral scanning, and the press technique (combined with 3D printing). Int J Prosthodont 2023;36:e103–e118