Oral function in completely edentulous patients rehabilitated with implant-supported dental prostheses: A systematic review and meta-analysis.

OBJECTIVES: This review evaluated the effects of rehabilitation with implant-supported prostheses on the oral function of completely edentulous adults. MATERIALS AND METHODS: Systematic literature searches were performed to identify records reporting on oral function in completely edentulous adults rehabilitated with implant-supported prostheses. Meta-analyses were performed on various outcomes including bite force, masticatory performance, muscle activity, mandibular movement/chewing pattern, and salivary flow. RESULTS: 5507 records were identified. Thirty studies qualified for data extraction and analysis. The kappa (𝛋) for the search and identification strategy ranged between 0.50 and 1.00. Meta-analysis was performed grouping the studies by outcomes and split by time points of 6-12 months, 12-36 months, and >36 months after implant therapy. The meta-analyses revealed a significant improvement in oral function of completely edentulous adults after rehabilitation with implant-supported prostheses at 6-12 months (Z = -4.895, p < .001; 95% CI: -0.703, -0.301; τ2 = .609; Q = 114.953, df = 17, p < .001; I2 = 85.2%), at 12-36 months (Z = -4.886, p < .001; 95% CI: -0.580, -0.248; τ2 = .908; Q = 280.611, df = 35, p < .001; I2 = 87.5%) and at more than 36 months (Z = -9.108, p < .001; 95% CI: -1.472, -0.951; τ2 = .019; Q = 7.918, df = 7, p = .340; I2 = 11.6%). The included studies demonstrated a low to moderate risk of bias. CONCLUSIONS: This systematic review concluded that the oral function of completely edentate adults significantly improved with implant-supported/retained prostheses, even when only one jaw received implant therapy. Therefore, implant therapy should be promoted for edentulous adults to alleviate the shortcomings of conventional complete removable dental prostheses.

Group 4 ITI Consensus Report: Patient benefits following implant treatment in partially and fully edentulous patients.

OBJECTIVES: The aim of Working Group 4 was to address patient benefits associated with implant dentistry. Focused questions on (a) dental patient-reported outcomes (dPROs), (b) improvement in orofacial function, and (c) preservation of orofacial tissues in partially and fully edentulous patients following provision of implant-retained/supported dental prostheses were addressed. MATERIALS AND METHODS: Three systematic reviews formed the basis for discussion. Participants developed statements and recommendations determined by group consensus based on the findings of the systematic reviews. These were then presented and accepted following further discussion and modifications as required by the plenary of the 7th ITI Consensus Conference, taking place in 2023 in Lisbon, Portugal. RESULTS: Edentulous patients wearing complete dentures (CD) experience substantial improvements in overall dPROs and orofacial function following treatment with either complete implant-supported fixed dental prostheses (CIFDP) or implant overdentures (IODs). With respect to dPROs, mandibular IODs retained by two implants are superior to IODs retained by one implant. However, increasing the number of implants beyond two, does not further improve dPROs. In fully edentulous patients, rehabilitation with CIFDP or IOD is recommended to benefit the preservation of alveolar bone and masseter muscle thickness. CONCLUSIONS: Completely edentulous patients benefit substantially when at least the mandible is restored using an CIFDP or an IOD compared to CD. In fully edentulous patients, implant prostheses are the best option for tooth replacement. The availability of this treatment modality should be actively promoted in all edentulous communities, including those with limited access and means.

CAD/CAM Complete Denture Resins: An In Vitro Evaluation of Color Stability.

PURPOSE: To evaluate the color stability of CAD/CAM complete denture resins. MATERIALS AND METHODS: A total of 176 resin specimens were manufactured from conventional heat-polymerizing (pink: CONHCP : n = 16; tooth-shade: CONHCT : n = 16), CAD/CAM subtractively manufactured (pink: WIMP : n = 16, AVMP : n = 16, MEMP : n = 16, POMP : n = 16; tooth-shade: AVMT : n = 16, MEMT : n = 16, POMT : n = 16), and additively manufactured (pink: NDRPP : n = 16; tooth-shade: NDRPT : n = 16) denture resins; four different aging processes (thermal cycling, distilled water, red-wine, and coffee) were used. A spectrophotometer evaluated the color change (ΔE) using two modes of measurements (specular component included (ΔESCI ) and specular component excluded (ΔESCE )) recorded at baseline (T0 ) and at day#30 (T30 ). ANOVA and post hoc tests were used for statistical analysis (alpha = 0.05). RESULTS: Additively manufactured resins (NDRPP and NDRPT ) demonstrated significant ΔE in comparison to the other groups in all aging media (p < 0.001). WIMP demonstrated higher ΔESCI in comparison to the other subtractively manufactured groups in distilled water (p < 0.001). In red-wine, AVMT revealed significantly more ΔESCE than POMT (p = 0.039). In coffee, the ΔESCE was higher for CONHCT than MEMT (p = 0.026) and POMT (p = 0.011). Similarly, in coffee the ΔESCE for AVMT was higher than POMT (p = 0.030). CONCLUSION: Additively manufactured denture resins demonstrated the maximum color change compared to conventional heat-polymerized and CAD/CAM subtractively manufactured denture resins. Furthermore, CAD/CAM subtractively manufactured denture resins were not inferior to conventional resins in terms of color stability.

Reliability of a face scanner in measuring the vertical dimension of occlusion.

OBJECTIVE: This study evaluated the reliability of a face scanner in measuring the vertical dimension of occlusion (VDO). METHODS: Fully dentate volunteers (n = 20; mean-age = 30.0 ± 10.7 years) were recruited. Clinical facial measurements were obtained using a digital caliper and a face scanner (Obiscanner, Fifthingenium, Italy). The scans were imported into a mesh-processing software, and the distances were measured digitally. Measurements were obtained for each participant with the jaws positioned in maximal intercuspation (MI) and with increased vertical distances of 2, 4, and 6 mm. Vertical and horizontal measures were obtained using facial anatomical landmarks: Glabella (GL), Pronasale (PrN), Subnasale (SbN), inferior border of the right and left Alare, Labiale superius (Ls), right and left Cheilion (Ch), Soft Pogonion (SPg), right and left Tragus of the ear (Tr), for all selected vertical positions. Data analysis included intra-class correlation coefficient (ICC), pairwise comparison tests, Bland-Altman plots, and Passing-Bablok regression. RESULTS: 120 VDO measurements (clinical=60, digital=60) were recorded by two independent evaluators. Mean differences between digital and clinical measurements ranged from 0.054 ± 0.14 mm to 0.203 ± 0.13 mm. All parameters were strongly correlated (r > 0.93; p < 0.001). ICC estimates revealed excellent reliability, and the measuring procedure yielded the same results on repeated trials irrespective of the raters and measurement methods. Bland-Altman plots revealed a difference, between digital and clinical measurements, of 1.7 % for the vertical measurements. Regression analysis revealed no significant proportional difference between the two methods, so both can be used interchangeably. CONCLUSIONS: The findings of this study demonstrate that VDO can be measured accurately from face scans using 3D mesh-processing software and that even small changes in the VDO could be detected using the digital methods. CLINICAL SIGNIFICANCE: Findings provide evidence about the reliability of a digital method for jaw relation registrations and may be applied towards incorporating this method into clinical workflows for computer-aided-design/ computer-assisted-manufacturing (CAD-CAM) dentures.

Survival analysis and prevalence of biological and technical complications in fully edentulous patients rehabilitated with different modalities of complete dentures: A retrospective study in Zurich (part I).

PURPOSE: This study aimed to evaluate the prevalence of biological and technical/mechanical complications in edentate elders rehabilitated with complete removable dental prostheses (CDs) and overdentures [tooth-retained (ODs), implant-retained (IODs)]. MATERIALS AND METHODS: Patient records of adults (>60y) rehabilitated with CDs, ODs, and IODs were included. Demographic information (age, sex), information on the prostheses type, number/type of biological/prosthetic complications, along with the number/time of the complications, were extracted.Kaplan-Meier model was used for the statistical analyses. RESULTS: 162 patients (mean age: 74.5±9.45y; prostheses: n=224, CD=172; OD=21; IOD=31) were included. The average period of function in situ was 19.70±27.66, 32.72±27.84, and 31.73±32.67 months, for the CDs, ODs, and IODs, respectively. 5 prostheses failed. Survival analysis revealed an overall survival rate (SR) of 97.8%, with individual five-year cumulative survival probability of 96.1% for CDs, 94.1% for ODs, and 100.0% for IODs. There were no significant survival differences between maxillary and mandibular prostheses within each type of rehabilitation. In the maxilla, no significant differences were found in maintenance visit times due to prosthodontic complications among the different types of prostheses. Patients with mandibular CDs required maintenance visits earlier compared to mandibular ODs (p<0.001) and IODs (p<0.001). Patients with mandibular ODs also required maintenance visits earlier than those with mandibular IODs (p=0.005). CONCLUSIONS: Rehabilitation of the edentate jaws, whether with CDs, ODs, or IODs, is a predictable treatment modality with high survival rates. Differences in maintenance visit times were observed, with CDs and ODs in the mandible requiring earlier visits compared to IODs.

CAD-CAM complete denture resins: Effect of relining on the shear bond strength.

OBJECTIVES: The aim of this study was to compare the shear bond strength of relined CAD-CAM complete removable dental prosthesis (CRDP) resins with conventional heat-polymerized polymethylmethacrylate (PMMA) resin. METHODS: A total of 96 resin specimens in identical dimensions of 10 mm × 10 mm × 11 mm were fabricated for four study groups [#1- Conventional heat-polymerized group: n=24 (ProBase); #2- Milled#1: n=24 (Ivobase); #3- Milled#2: n=24 (Ivotion); #4- 3D-printed: n=24, (NextDent Denture 3D+)]. Twelve specimens in each group were sectioned in the middle to produce a 3 mm defect and then were relined using a conventional denture relining material. All specimens underwent thermocycling (5-55°C) for 10,000 cycles. The shear bond tests were carried out in a universal testing machine. One-way ANOVA and Tukey's test were used for statistical analysis (p<0.05). The two-parameter Weibull distribution values were calculated. RESULTS: Relined 3D-printed specimens had a significantly lower shear bond strength when compared with conventional (p=0.0003) and milled groups (Milled#1: p=0.0004; Milled#2: p<0.0001). There were no differences in the shear bond strengths between the milled and conventional groups. Weibull distribution presented the highest shape value for the non-relined Milled#1 (22.83) group and the lowest values for the 3D-printed relined group (4.001). CONCLUSION: The findings of this study conclude that the shear bond strength of the conventionally-relined 3D-printed resins used for fabricating CRDPs was inferior to the shear bond strength of conventionally-relined resins employed for manufacturing CRDPs using CAD-CAM milling and conventional heat-polymerization techniques. CLINICAL SIGNIFICANCE: When considering 3D-printing for the fabrication of CRDPs, it is recommended to employ it in clinical situations where a frequent need for denture relining is not expected.

Analysis of the residual monomer content in milled and 3D-printed removable CAD-CAM complete dentures: an in vitro study.

OBJECTIVE: The study aimed to quantitatively evaluate the elution of methylmethacrylate from CAD-CAM manufactured removable complete dentures (RCDs) using high performance liquid chromatography (HPLC). METHODS: Thirty-two RCDs were manufactured following either the CNC-milling (Milled: n=8) or the 3D-printing (n=24) protocols. The 3D-printed dentures were further categorized into three groups based on their post-production rinsing cycles [Extended wash cycle (EWC), Standard wash cycle (SWC), and SWC with an additional Durécon coating (SWC2)]. HPLC was used to evaluate the methylmethacrylate concentrations (MMCs) eluted from the dentures in each group for different time periods (1, 2, 4, 8, and 24 hours). Mean and standard deviations were calculated for the MMCs; data was verified for normal distribution, ANOVA and post hoc tests were applied for statistical analyses (⍺=0.05). RESULTS: The HPLC revealed that all the denture groups recorded some amounts of MMCs, with significant differences [F (3, 31) = 23.646, p<0.0001]. The milled denture group had the highest MMCs at 24 hours when compared to the EWC (p<0.0001), SWC (p=0.001), and SWC2 (p<0.0001) denture groups. SWC had a higher MMC than EWC (p=0.032) and SWC2 (p=0.015). No differences were found in MMCs when comparing EWC and SWC2 (p=0.989). CONCLUSION: Methylmethacrylate concentrations were significantly lower in 3D-printed RCDs than in milled RCDs when using the resins employed in this study. Furthermore, the MMCs can be further decreased in 3D-printed RCDs when coated with an additional thin protective layer (Durécon) by following the manufacturer-recommended rinsing protocol or when an extended isopropanol wash cycle is adopted.

CAD-CAM removable complete dentures: A systematic review and meta-analysis of trueness of fit, biocompatibility, mechanical properties, surface characteristics, color stability, time-cost analysis, clinical and patient-reported outcomes.

OBJECTIVES: This review compared Computer-aided designand Computer-aided manufactured (CAD-CAM) and conventionally constructed removable complete dentures (CDs). DATA: Seventy-three studies reporting on CAD-CAM (milled/3D-printed) CDs were included in this review. The most recent literature search was performed on 15/03/2021. SOURCES: Two investigators searched electronic databases [PubMed (MEDLINE), Embase, CENTRAL], online search engines (Google) and research portals. Hand searches were performed to identify literature not available online. STUDY SELECTION: Studies on CAD-CAM CDs were included if they reported on trueness of fit, biocompatibility, mechanical, surface, chemical, color , microbiological properties, time-cost analysis, and clinical outcomes. Inter-investigator reliability was assessed using kappa scores. Meta-analyses were performed on the extracted data . RESULTS: The kappa score ranged between 0.897-1.000. Meta-analyses revealed that 3D-printed CDs were more true than conventional CDs (p = 0.039). Milled CDs had a higher flexural-strength than conventional and 3D-printed CDs (p < 0.0001). Milled CDs had a higher flexural-modulus than 3D-printed CDs (p < 0.0001). Milled CDs had a higher yield-strength than injection-molded (p = 0.004), and 3D-printed CDs (p = 0.001). Milled CDs had superior toughness (p < 0.0001) and surface roughness characteristics (p < 0.0001) than other CDs . Rapidly-prototyped CDs displayed poor color-stability compared to other CDs (p = 0.029). CAD-CAM CDs d displayed better retention than conventional CDs (p = 0.015). Conventional CDs had a higher strain at yield point than milled CDs (p < 0.0001), and had superior esthetics than 3D-printed (p < 0.0001). Fabrication of CAD-CAM CDs required less chairside time (p = 0.037) and lower overall costs (p < 0.0001) than conventional CDs. CONCLUSIONS: This systematic review concludes that CAD-CAM CDs offer a number of improved mechanical/surface properties and are not inferior when compared to conventional CDs. CLINICAL SIGNIFICANCE: CAD-CAM CDs should be considered for completely edentulous patients whenever possible, since this technique offers numerous advantages including better retention, mechanical and surface properties but most importantly preserves a digital record. This can be a great advantage for older adults with limited access to dental care.

CAD-CAM complete denture resins: an evaluation of biocompatibility, mechanical properties, and surface characteristics.

OBJECTIVES: This study evaluated the biocompatibility, mechanical properties, and surface roughness of CAD-CAM milled and rapidly-prototyped/3D-printed resins used for manufacturing complete dentures. METHODS: Six groups of resin specimens were prepared, milled-base (MB), milled-tooth shade (MT), printed-tooth shade (PT), printed-base with manufacturer-recommended 3D-printer (PB1), printed-base with third-party 3D-printer (PB2), printed-base in a vertical orientation (PB2V). Human epithelial (A-431) and gingival (HGF-1) cells were cultured and tested for biocompatibility using Resazurin assays. Three-point bending and nanoindentation tests measured the mechanical properties of the resin groups. Surface roughness was evaluated using a high-resolution laser profilometer. ANOVA and post-hoc tests were used for statistical analyses (α = 0.05). RESULTS: There were no significant differences in biocompatibility between any of the investigated groups. MB revealed a higher ultimate strength (p = 0.008), elastic modulus (p = 0.002), and toughness (p = 0.014) than PB1. MT had significantly higher elastic modulus than PT (p < 0.001). Rapidly-prototyped resin samples with a manufacturer-recommended 3D-printer (PB1) demonstrated higher ultimate strength (p = 0.008), elastic modulus (p < 0.001), hardness (p < 0.001) and a reduced surface roughness (p < 0.05) when compared with rapidly-prototyped groups using a third-party 3D-printer (PB2). Rapidly-prototyped samples manufactured with a vertical printing orientation (PB2V) revealed a significantly lower elastic modulus than samples groups manufactured using horizontal printing orientation (PB2) (p = 0.011). CONCLUSIONS: Within the limits of this present study, CAD-CAM milled and rapidly-prototyped complete denture resins performed similarly in terms of biocompatibility and surface roughness. However, the milled denture resins were superior to the rapidly-prototyped denture resins with regard to their mechanical properties. Printing orientation and type of 3D-printer can affect the resin strength and surface roughness.

Changes in Oral Health Policies and Guidelines During the COVID-19 Pandemic.

The aim of this study was to describe the changes in oral health policies and guidelines in response to the Coronavirus disease 2019 (COVID-19) pandemic in different countries and regions around the world. Information on oral health policies and guidelines from 9 countries (Canada, China including Hong Kong, Egypt, India, Japan, New Zealand, Nigeria, Switzerland, and Thailand) were summarized, and sources of the information were mostly the national or regional health authorities and/or dental council/associations. The changes made to the oral health guidelines depended on the severity of the COVID-19 pandemic. This included suspension of non-emergency dental care services at the peak of the COVID-19 outbreak, and easing the restrictions on non-essential and elective dental care when the pandemic became under control. The COVID-19 risk mitigation strategies include strict adherence to infection control practices (use of hand sanitizers, facemask and maintaining social distancing), reducing the amount of aerosol production in the dental setting, and managing the quality of air in the dental treatment rooms by reducing the use of air conditioners and improving air exchange. The COVID-19 pandemic has shown a major impact on dental practice. Dental professionals are trying to adapt to the new norms, while the medium to long-term impact of COVID-19 on dentistry needs further investigation.