Targeting bonding protocols to increase the bond between acrylic resin or 3D printed denture bases and prefabricated or 3D printed denture teeth.

STATEMENT OF PROBLEM: The difference in chemical composition between denture base resin and denture teeth requires the development of bonding protocols that increase the union between the materials. PURPOSE: The purpose of this in vitro study was to evaluate the impact of different bonding protocols on the bond between heat-polymerized and 3-dimensionally (3D) printed acrylic resin denture bases and acrylic resin prefabricated and 3D printed artificial teeth. MATERIAL AND METHODS: Four types of artificial teeth were evaluated: prefabricated acrylic resin (VITA MFT) and 3D printed (Cosmos TEMP, PRIZMA 3D Bio Denture, and PrintaX AA Temp) bonded to 20×24-mm cylinders of heat-polymerized (VipiWave) and 3D printed (Cosmos Denture, PRIZMA 3D Bio Denture, and PrintaX BB Base) denture bases. Three bonding protocols were tested (n=20): mechanical retention with perforation + monomer (PT1), mechanical retention with perforation + airborne-particle abrasion with 50-µm aluminum oxide + monomer (PT2), and mechanical retention with perforation + Palabond (PT3). Half of the specimens in each group received 10 000 thermocycles and were then subjected to the bonding test at a crosshead speed of 1 mm/minute. The failure type was analyzed and scanning electron micrographs made. Additionally, surface roughness (Ra) and wettability (degree) were analyzed (n=15). ANOVA was used to evaluate the effect of the bonding protocol, and the Student t test was applied to compare the experimental groups with the control (α=.05). For type of failure, a descriptive analysis was carried out using absolute and relative frequency. The Kruskal-Wallis test was used to evaluate the surface changes (α=.05). RESULTS: Among the protocols, PT3 with in Yller and PT2 with Prizma had the highest bond strengths of the heat-polymerized denture base and 3D printed teeth (P<.05). When comparing the experimental groups with the control, PT3 and PT2 had greater union with the 3D printed denture base + 3D printed teeth (in Yller), with no difference from the heat-polymerized denture base + prefabricated teeth in acrylic resin. The treatment of the 3D printed tooth surfaces affected the surface roughness of Prizma (P<.001) and wettability (P<.001). CONCLUSIONS: To increase the bond between Yller 3D printed denture base + 3D printed teeth, a bonding protocol including mechanical retention with perforation + Palabond or mechanical retention with perforation + airborne-particle abrasion with aluminum oxide + monomer is indicated. For the other materials tested, further bonding protocols need to be investigated.

Device trueness in passivity and misfit of CAD-CAM frameworks: Conventional versus printed casts.

STATEMENT OF PROBLEM: Obtaining a passive and well-adapted framework is challenging when intraoral scanning edentulous arches with multiple implants. The trueness of the printed casts is unclear. PURPOSE: The purpose of this clinical study was to evaluate the trueness of frameworks made from conventional and printed casts regarding clinical passivity and misfit. MATERIAL AND METHODS: Ten participants with complete mandibular fixed implant-supported interim prostheses retained by 4 implants were included. Each participant had a conventional impression and a digital scan made. The digital scan was made using an innovative device. Both conventional and digital casts were made, and the virtual images were used for milling the digital framework in cobalt chromium alloy. All frameworks were evaluated for passivity and marginal vertical misfit with the single screw test, with 4 attempts consisting of the tightened screw position, a test with all screws tightened, and an interspersed tightening test. The Kruskal-Wallis test was used to evaluate the trueness of the tested device for framework construction through the single screw test on vertical marginal misfit in the conventional and printed groups (α=.008). The Friedman test was used to assess the effect of test type (α=.05), and the Wilcoxon test was used to identify group-to-group differences (α=.017). RESULTS: The absence of space between the framework and the abutments and interferences during its placement, as well as good stability, were observed clinically. In laboratory analysis, greater framework misfits were observed in the printed group compared with the conventional group when the single screw test was applied. Comparing the 3 tests used, the greatest misfits were observed when the framework was screwed onto the printed cast. CONCLUSIONS: The innovative device tested for the intraoral scanning of multiple implants had clinically acceptable accuracy for the construction of passive and adapted frameworks. The conventional cast was more accurate than the printed cast, with lower misfit values, in all tests.

Conventional and digital impressions for complete-arch implant-supported fixed prostheses: time, implant quantity effect and patient satisfaction.

PURPOSE: To evaluate and compare the effect of impression type (conventional vs digital) and the number of implants on the time from the impressions to the generation of working casts of mandibular implant-supported fixed complete-arch frameworks, as well as on patient satisfaction. MATERIALS AND METHODS: 17 participants, 3 or 4 implants, received 2 types of digital impression methods (DI) and conventional (CI). In DI, two techniques were performed: scanning with the scan bodies (SC) and scanning with a device attached to the scan bodies (SD) (BR 10 2019 026265 6). In CI, the making of a solid index (SI) and open-tray impression (OT) were used. The outcomes were used to evaluate the time and the participant satisfaction with conventional and digital impressions. The time was evaluated through the timing of the time obtained in the workflow in the conventional and digital impression. The effect of the number of implants on time was also assessed. Satisfaction was assessed through a questionnaire based on seven. The Wilcoxon test used to identify the statistical difference between the groups in terms of time. The Mann-Whitney test was used to analyze the relationship between the time and the number of implants. Fisher's test was used to assess the patient satisfaction (P < .05). RESULTS: The time with DI was shorter than with CI (DI, x̃=02:58; CI, x̃=31:48) (P < .0001). The arches rehabilitated with 3 implants required shorter digital impression time (3: x̃=05:36; 4: x̃=09:16) (P < .0001). Regarding satisfaction, the DI was more comfortable and pain-free than the CI (P < .005). CONCLUSION: Digital impressions required shorter chair time and had higher patient acceptance than conventional impressions.

Incidence and risk factors for non-adaptation of new mandibular complete dentures: a clinical trial.

OBJECTIVE: To investigate the incidence and risk factors for non-adaptation of the conventional mandibular complete denture (CMCD). MATERIALS AND METHODS: A total of 108 edentulous patients were rehabilitated with complete dentures (CDs) and followed up at 3- and 6-month intervals. Adaptation was confirmed based on chewing, phonetics, and comfortable swallowing with the CDs. The risk factors among sociodemographic and patient-centered factors were analyzed. Statistical analyses included the chi-square test and then a multivariate analysis. RESULTS: After 3 months, 38.0% of patients showed non-adaptation to CMCDs. Non-adaptation was significantly associated with the absence of previous mandibular denture experience (p = 0.042), ulcerations after 15 days of rehabilitation (p < 0.001), and a reduced posterior mandibular ridge (p = 0.035). After 6 months, this incidence decreased to 14.1%. The factors associated with non-adaptation were ulcerative lesions after 15 (p < 0.001) and 30 (p < 0.001) days of the delivery of CDs and the non-regular use of mandibular CDs (p < 0.001). CONCLUSION: The incidence of non-adaptation was higher after 3 months, with reduction after 6 months. Sociodemographic variables did not influence the adaptation. After 3 months, the absence of previous experience, traumatic ulcers, and reduced mandibular ridges hindered the adaptation of patients to mandibular CDs. After 6 months, only the occurrence of ulcerative lesions and non-regular wear of dentures were risk factors for non-adaptation. CLINICAL RELEVANCE: A considerable number of patients have difficulties in adapting to the mandibular dentures. Identifying the factors of non-adaptation of the dentures will contribute to increasing the predictability of this critical adaptation period.

Factors associated with edentulous patients' willingness about implant-supported complete denture: a multivariate analysis.

OBJECTIVE: The aim of this study was to evaluate the factors influencing edentulous patients' willingness about mandibular implant-supported complete denture. MATERIALS AND METHODS: A cross-sectional study was carried out with 117 bimaxillary edentulous patients wearing removable complete dentures (CDs). Patients were assessed concerning denture-related items (number of previous mandibular CDs, previous denture wearing period, dentures maker professional, and regular wearing of previous mandibular dentures) and individual-related aspects, such as mandibular edentulousness period, mandibular bone height, and willingness to the use of mandibular implant-supported complete denture. Masticatory performance was evaluated by the median particle diameter. Mandibular bone height and satisfaction were assessed using a validated method. The Chi-square test was used for data analysis and prevalence ratios were adjusted by using multivariate Poisson regression, both with 95% confidence interval. RESULTS: A total of 78 participants (66.7%) were interested in mandibular implant-supported overdenture (mean age 65.33 ± 9.49). Masticatory performance was not influenced by choosing mandibular implant-supported complete denture. The preference about mandibular implant-supported complete denture was correlated with longer mandibular complete denture experience (p = 0.021) and it was significantly associated with dissatisfaction about retention (p = 0.005). CONCLUSION: Previous experience with mandibular complete dentures and dissatisfaction about retention influence the willingness about mandibular implant-supported overdenture. CLINICAL RELEVANCE: Many factors are associated with rehabilitation preferences for edentulous patients and mandibular implant-supported complete denture is one of the available alternatives. Therefore, this study has demonstrated the factors influencing the decision to replace a mandibular conventional complete denture by dental implant treatment based on patient's outcomes. Such finding may be considered as a relevant aspect towards shared decision-making for prosthodontic rehabilitation of edentulous patients.

Improvement in Quality of Life of Elderly Edentulous Patients with New Complete Dentures: A Systematic Review.

PURPOSE: To evaluate whether treatment with new complete dentures improves quality of life in elderly patients. MATERIALS AND METHODS: A literature search was conducted in the MEDLINE/PubMed, Scopus, LILACS, SciELO, Web of Science, and Cochrane Library databases using specific keywords for relevant articles published up to March 2018. Three reviewers obtained the data and compared the results from reports that evaluated denture wearers 60 years of age or older whose old dentures were replaced with new ones. RESULTS AND CONCLUSION: Of 282 published studies, 7 met the inclusion criteria (5 evaluated quality of life before and after treatment using the Oral Health Impact Profile, 1 using the Oral Impacts by Daily Performance, and 1 using the Geriatric Oral Health Assessment Index). The articles showed a similar increase in quality of life after elderly patients were treated with new complete dentures; however, the limited methodologic quality in the reported and analyzed studies underscores the need for more robust controlled investigations to strengthen the current body of evidence, which is limited.

Technical Quality of Complete Dentures: Influence on Masticatory Efficiency and Quality of Life.

PURPOSE: To evaluate the effect of the technical quality of conventional complete dentures (CD) on masticatory efficiency and quality of life (QoL) of denture wearers during a 1-year follow-up. MATERIALS AND METHODS: A prospective clinical trial with 32 edentulous patients (mean age of 60.2 years) wearing mandibular and maxillary dentures was conducted. All patients were evaluated wearing their preexisting dentures and after 3, 6, and 12 months postinsertion of new dentures. A reproducible method for objective evaluation of the technical quality of CDs was employed. Masticatory efficiency was evaluated by the colorimetric method using beads as artificial testing food. The oral health impact on patient QoL was measured using the OHIP-EDENT (Oral Health Impact Profile in Edentulous Adults) questionnaire. The nonparametric Wilcoxon test was applied to reveal any differences in technical quality between the preexisting and new dentures. The Friedman test was used to detect differences in masticatory efficiency and oral health impact on QoL. Spearman's correlation was applied to reveal correlation between the variables. RESULTS: Comparing preexisting and new dentures, significant improvement was found in technical quality between the dentures (p < 0.001). There was no statistically significant difference in masticatory efficiency. A significant decrease was found in the total OHIP-EDENT scores after denture replacement. A positive correlation was found between technical quality and OHIP in the new denture wearers (p = 0.011). CONCLUSIONS: According to the results of this study, denture quality significantly improved patients' oral health-related QoL; however, insertion of new dentures did not influence masticatory efficiency.

Comparative evaluation of peri-implant tissues in patients wearing mandibular overdenture with different implant platforms.

BACKGROUND: The poor hygiene of peri-implant tissues causes inflammation at tissue-implant interface, which may impair the rehabilitation success. The aim of this study was to evaluate the influence of external hexagon and Morse taper implants on peri-implant health in patients wearing mandibular overdentures for 1 year. MATERIALS AND METHODS: A total of 46 implants were evaluated, 28 external hexagon and 18 Morse taper. Plaque index in the mini-abutment, bleeding index, peri-implant inflammation, keratinized mucosa zone, probing depth, and marginal mucosa level were evaluated after 3 months and 1 year of prostheses insertion. RESULTS: Deeper probing was found in the external hexagon group compared with Morse taper (P = 0.024) after 1 year of rehabilitation. Although the Morse taper group exhibited worse scenario of peri-implant inflammation than the external hexagon group (P = 0.001), both groups showed reduced inflammation after 1 year. A larger keratinized mucosa zone was observed with external hexagon implants (P = 0.020). No significant difference was found between the groups for plaque index in the mini-abutment, bleeding index, and marginal mucosa level. CONCLUSION: In a follow-up period of 1 year, it was concluded that the external hexagon group had a larger probing depth than the Morse taper group. However, better periodontal conditions about inflammation and keratinized mucosa zone were found in external hexagon implants. It was found no influence of implant platform on plaque index in the mini-abutment, bleeding index, and marginal mucosa level.

Inhibitory effect of cranberry extract on periodontopathogenic biofilm: An integrative review.

BACKGROUND: Combating biofilm-dependent oral infections involves the use of synthetic antibiotics, which are often associated with bacterial resistance and adverse effects. As a result, herbs such as cranberry have emerged as an alternative treatment. The aim of this study was to evaluate, through an integrative literature review, the effectiveness of cranberry extract on cultures and biofilms of periodontopathogenic bacteria. MATERIALS AND METHODS: In vitro and in vivo studies evaluating the action of cranberry extract on the growth, coaggregation and formation of periodontopathogenic bacteria and periodontal biofilm were identified. Searches were carried out in the "Cochrane Library," "MEDLINE," "Web of Science," "Scopus," "LILACS," "Scielo," and "Google Scholar" databases, using the terms: "vaccinium macrocarpon;" "cranberries;" "cranberry;" "biofilms;" "periodontitis;" "chronic periodontitis;" "aggressive periodontitis;" "periodontal diseases;" and "periodont*." RESULTS: a low number of studies evaluating the effectiveness of cranberry extract on periodontal disease were found, and no human studies were identified. In general, the eight studies included in the revision found that the compounds effectively inhibited the formation of a biofilm of Porphyromonas gingivalis and Fusobacterium nucleatum at concentrations equal or superior to 62.5 µg/ml, but did not significantly inhibit bacterial growth or promote the breakdown of preformed biofilm. CONCLUSIONS: while most of the studies presented certain methodological limitations, they did identify an inhibiting effect of cranberry on periodontal bacteria. These results serve as support for the development of further studies evaluating the most effective vehicle and ideal concentration that can be used without causing adverse effects on oral tissues.