Mandibular overdentures retained by 1 or 2 implants: a 5-year randomized clinical trial on implant stability and peri-implant outcomes.

AIM: This is a report of the 5-year results of a two-group parallel randomized clinical trial comparing longitudinal implant stability, and clinical and radiographic peri-implant outcomes of mandibular overdentures retained by one (1-IOD group) or two (2-IOD group) implants. METHODS: All participants received 4.1 mm diameter tissue-level implants (Straumann® Standard Plus - SLActive®, Institut Straumann AG), installed in the mandible midline (1-IOD; n = 23) or the lateral incisor-canine area bilaterally (2-IOD; n = 24), and loaded after 3 weeks. Implant Stability Quotient (ISQ) was measured using a resonance frequency device (Osstell® Mentor, Integration Diagnostics) at implant placement, after three weeks (loading), and at the 6-month, 1-, 3-, and 5-year follow-ups. Marginal bone loss and clinical implant outcomes (plaque, calculus, suppuration and bleeding) were assessed periodically up to 5 years after loading. RESULTS: Only minor changes in marginal bone level were observed after 5 years (mean = 0.37; SD = 0.44 mm), and satisfactory and stable peri-implant parameters were observed throughout the 5-year follow-up. No significant differences between groups were found. Overall, the mean primary implant stability was considered high (> 70) for the two groups (1-IOD = 78.1 ± 4.5; 2-IOD = 78.0 ± 5.8). No noticeable changes were observed between implant insertion and loading. A marked increase was observed from insertion to the 6-month follow-up - the mean difference for the 1-IOD group was + 5.5 ± 5.5 (Effect size = 1.00), while for the 2-IOD group, the mean difference was + 6.0 ± 5.6 (Effect size = 1.08). No relevant changes were observed throughout the follow-up periods up to 5 years. Linear mixed-effect model regression showed no influence of the bone-related variables (p > 0.05) and the number of implants (p = 0.087), and a significant effect of the time variable (p < 0.001). CONCLUSION: Satisfactory peri-implant outcomes and stable secondary stability suggest good clinical performance and successful long-term osseointegration of the implants for single and two-implant mandibular overdentures. Using a single implant to retain a mandibular overdenture does not seem to result in detrimental implant loading over the five years of overdenture use. CLINICAL RELEVANCE: This study corroborates the use of a single implant to retain a mandibular denture.

Mandibular overdenture retained by four one-piece titanium-zirconium mini implants: A 2-year RCT on patient-reported outcomes.

AIM: The positive impact of implant interventions on dental patient-reported outcomes is an essential parameter of treatment effectiveness. This study assessed the 2-year changes in patient satisfaction and oral health-related quality of life (OHRQoL) of edentulous patients treated with a four mini implant mandibular overdenture (IOD) METHODS: The study was planned as a 2 × 2 factorial randomized clinical trial that tested two surgical approaches (flapped or flapless) and two loading protocols (immediate and delayed) using a titanium-zirconium mini implant (Straumann Mini Implant System®) and a PEEK retentive system (Straumann® Optiloc® Retentive System). Outcome measures (OHIP-Edent scores and the McGill Denture Satisfaction questionnaire) were assessed before treatment and at the 3-, 6-, 12-, and 24-month follow-ups. The Friedman test and multiple regression using Generalized Estimating Equations (GEE) were used for data analysis, considering the per-protocol (PP) and intention-to-treat (ITT) approaches RESULTS: Seventy-four patients were randomized to the study groups. No implant failure occurred during the study period. Marked improvement in all post-treatment periods compared to baseline were observed for the two outcomes. No significant effect of patient's gender, age, and surgical protocol on the study outcomes. The effect of treatment provision was significant for the two outcomes in the PP and ITT approaches (p < 0.001). A barely significant positive effect of the immediate loading was observed for OHIP-Edent in the PP approach (p = 0.020) CONCLUSION: IOD treatment significantly improved patient-reported outcomes measures, with sustained benefits over the two years of overdenture use, and can be considered a promising treatment option in for the edentulous mandible.

Mandibular overdenture retained by four one-piece titanium-zirconium mini implants: A 2-year follow-up on prosthodontic outcomes.

OBJECTIVE: This 2-year prospective study reports the incidence of prosthetic complications and maintenance events after treatment with mandibular overdenture retained by four mini implants opposed to a maxillary denture. METHODS: Implant intervention included flapless or flapped surgery combined with immediate or delayed loading, as part of a randomized clinical trial. Four one-piece titanium-zirconium mini-implants (Straumann Mini Implant System) were inserted, and the retentive PEEK elements (Optiloc) were incorporated into the overdenture using chairside procedures. Prosthodontic complications and maintenance events were recorded over a 2-year follow-up, and the final outcome was defined according to standardized criteria. Data analysis included descriptive statistics, incidence and incidence density rates, and Kaplan-Meier survival. RESULTS: 73 out of 74 patients (64.9 % female), mean age of 64 (SD=8.2) years, completed the study follow-up (one withdrew after 9 months). Implant survival was 100 %. A total of 163 prosthodontic events occurred in 53 patients (72.6 %), and 20 patients had no clinical complaints or maintenance needs. The most common procedures were adjustment/repair of the overdenture base (47.0 %), replacement of retentive inserts (19.8 %), and laboratory relining (12.9 %). A high prosthodontic success rate was achieved (93.2 %), and all patients presented serviceable overdentures and continuous use after the resolution of prosthodontic complications. The incidences of matrix replacement and laboratory relines were low in the first year, while denture base adjustments were common within the first year, especially in the first 6 months. CONCLUSION: The mini implant system showed high prosthodontic success rates. Minor adjustments/repairs during the initial follow-up were common. Relines and matrix replacements tend to occur after one year of overdenture use, and matrix replacements may occur as a consequence of the need for relining.

A cross-sectional CBCT assessment of the relative position of one-piece titanium-zirconium mini-implants placed for mandibular overdentures using non-guided surgery.

OBJECTIVE: To assess the relative position of mini-implants to retain a mandibular overdenture, according to the surgical protocol, technical and anatomical factors. METHODS: Mandibular cone-beam computed tomography (CBCT) scans were analyzed for 73 patients who received four one-piece titanium-zirconium mini-implants. Drilling was performed using a 1.6 mm needle drill and a 2.2 mm Pilot Drill, according to the bone density with a surgical stent. Post-insertion CBCT images in DICOM format were analyzed using the E-Vol-DX software with BAR filters. Divergence angle between implants and between implants and the overdenture path of insertion was measured using CliniView 10.2.6 software. RESULTS: Divergence between implants ranged from 0° to 22.3° (mean = 4.2; SD = 3.7) in the lateral and from 0° to 26.2° (mean = 5.3; SD = 4.1) in the frontal projections (p < .001). Only 1 (0.2%) and 3 (0.7%) of the measurements were higher than 20° in the lateral and frontal views, respectively. The mean angulations between the implant and the path of insertion for the overdenture were 9.3° (SD = 7.5) and 4.0° (SD = 2.9) for the lateral and frontal views, respectively (p < .001). Regression analyses showed a significant association between the divergence of implants and the frontal view projection (p < .001), greater distance between the paired implants (p = .017), the flapped surgical protocol (p = .002), higher final insertion torque (p = .011), and deeper preparation with the needle drill (p < .001). CONCLUSIONS: The mini-implants were placed with low divergence angles and satisfactory parallelism. Factors including shorter distances between the implants, higher density bone, and a flapless surgical approach all contributed positively to improved parallelism of the mini-implants.

Four-year assessment of masticatory function in mandibular overdenture wearers: A randomised clinical trial comparing two to four implants to retain the prosthesis.

BACKGROUND: Limited data exist on the mid- to long-term masticatory capacity of mandibular overdenture (IOD) wearers, particularly regarding the use of posterior implants to retention. OBJECTIVES: To periodically evaluate mastication of IOD wearers, comparing the effectiveness of two to four implants to retain the prosthesis. METHODS: In a randomised controlled clinical trial, 20 complete edentulous patients (14 women), aged 51-84 years (mean age 69.1 ± 9.6), received new bimaxillary complete dentures (CD). After adaptation, baseline measurements of masticatory performance (X50) and swallowing threshold were conducted using the sieving method. Patients were then randomly assigned to groups: control (two intra-foraminal regular implants) and experimental (two intra-foraminal regular implants and two extra-short posterior implants) (n = 10 each). After 4 months, implants were splinted, and a new mandibular IOD was fabricated with bar/clip retention. Mastication was reassessed after 6, 12, and 48 months, and data analysed with repeated measures ANOVA and Sidak's post hoc (α = 0.05). RESULTS: Despite a loss of two patients per group, masticatory performance significantly improved after mandibular IOD installation (p = .031) in both groups (p = .670). A second improvement was observed after 6 months (p = .027), with no subsequent changes (p > .05). Swallowing threshold improvements were noted with IOD, and no discernible differences between groups were observed (p > .05). CONCLUSION: Masticatory function significantly improved after mandibular IOD installation, with the number of implants demonstrating minimal influence. CLINICAL TRIAL REGISTRATION: The present study was not registered in a public database, as mandated. It is important to note that the recommendation for registration was initiated in 2017 by the Committee of Medical Journal Editors, while patient inclusion in the research took place in 2016. Given that the data presented in this manuscript cover a follow-up period of up to 4 years post-surgical intervention, delayed registration was not feasible.

Changes in masticatory performance and bite force after treatment with mandibular overdentures retained by four titanium-zirconium mini implants: One-year randomised clinical trial.

OBJECTIVE: This prospective study is part of a randomised clinical trial and reports the changes in masticatory performance (MP) and bite force, and explores their influential factors, 1 year after the provision of mandibular overdentures retained by four titanium-zirconium mini implants. METHODS: Edentulous patients received conventional complete dentures, followed by placement of four mini implants (Straumann® Mini Implant System) in the anterior mandible and converting the conventional prosthesis into a mandibular overdenture. Treatment protocols were randomised using a 2×2 factorial design combining different surgical (flapped vs. flapless) and loading (immediate vs. delayed) protocols. MP was assessed using a two-colour mixing ability test and a colorimetric analysis to measure the level of colour mixing (Variance of Hue-VoH). Maximum voluntary bite force (MBF) was measured by a digital gnathodynamometer in the posterior and anterior regions. Sex, age, surgical and loading protocols and ridge morphology were tested as independent variables. MP and MBF tests were performed at baseline (pre-treatment) and the 3-, 6- and 12-month after implant loading. Descriptive statistics, independent t-test, and linear mixed-effect model (LMM) regression were used for data analysis. RESULTS: Seventy-four participants were assessed and 73 completed the 1-year follow-up. Statistically significant improvements in functional parameters were observed in all follow-up periods compared to baseline (p < .001). The flapless protocol was associated with higher improvement in MP at the 3-month follow-up (p = .004), while less resorbed ridges were associated with better MP (p = .038) and higher MBF (p < .001). CONCLUSION: The mandibular overdenture protocol using four titanium-zirconium mini implants was effective in improving MP and MBF of edentulous patients, compared to pre-treatment values. The findings also suggest that improvements in chewing function and bite force are impacted by clinical factors since better outcomes were observed for flapless surgeries and less resorbed edentulous ridges. CLINICAL TRIAL REGISTRATION: ClinicalTrials.Gov ID NCT04760457.

Estudio in vitro del ajuste de supraestructuras pasivadas sobre implantes múltiples / In vitro study of the adjustment of passivated suprastructures on multiple implants

Resumen Objetivo Comparar dos procedimientos de soldadura convencionales empleando una aleación de Cr-Co, para conectar barras coladas seccionadas a ser fijadas sobre implantes. Materiales y métodos A partir de un modelo maestro que representa un maxilar desdentado con cuatro implantes, se confeccionaron veinte (n=20) probetas seccionadas en tres partes. Se conformaron dos grupos, cada uno con diez (n=10) ejemplares. Una vez acondicionadas, fueron atornilladas al modelo maestro. Su desajuste inicial se analizó utilizando una lupa estereoscópica, con una cámara incorporada y un software. Las partes fueron soldadas empleando un procedimiento diferente para cada grupo. Las correspondientes al Grupo I se invistieron en un block refractario a base de sílico-fosfato. Las del Grupo II se montaron en una estructura metálica Clever Spider. El desajuste fue mensurado y los resultados procesados estadísticamente. El nivel de significación fue establecido en p<0,05. Resultados El Grupo I tuvo un desajuste inicial de 97,30±13,81μm y el Grupo II de 98,53±11,24μm. Luego de la soldadura, el Grupo I registró 98,53±17,17μm, 1,23μm mayor respecto al inicial. En el Grupo II se observó 103,13±17,61μm, 4,60μm por encima del original. Se analizaron mediante prueba t de Student; en ambos casos el resultado fue de p>0,05. Al comparar entre sí los grupos I y II, por medio de la prueba t y de comprobación no paramétrica de Mann-Whitney, se observaron diferencias no significativas, p=0,41 y p=0,38 respectivamente. Conclusiones Bajo las condiciones de este estudio, se observó que los dos métodos de soldadura analizados fueron confiables para unir supraestructurasos metálicas sin que se afecte su ajuste final.

Abstract Aim Compare two conventional welding procedures using a Cr-Co alloy, to connect sectioned cast bars to be fixed on implants. Materials and methods From a master model representing a toothless jaw with four implants, twenty (n=20) specimens sectioned into three parts were made. Two groups were formed, each with ten (n=10) specimens. Once conditioned, they were screwed to the master model. Its initial mismatch was analyzed using a stereoscopic magnifier, with a built-in camera and a software. The parts were welded using a different procedure for each group. Those corresponding to Group I were invested in a refractory block based on silyl-phosphate. Those of Group II were mounted on a Clever Spider metal structure. The mismatch was measured, and the results processed statistically. The level of significance was established at p<0.05. Results Group I had an initial mismatch of 97.30 ±13.81μm, and Group II of 98.53±11.24μm. After welding, Group I registered 98.53±17.17μm, 1.23μm higher than the initial one. In Group II, 103.13±17.61μm was observed, 4.60μm above the original. They were analyzed using Student's t test; in both cases the result was p>0.05. When comparing groups I and II, using the t-test and the Mann-Whitney nonparametric verification, non-significant differences were observed, p=0.41 and p=0.38 respectively. Conclusions Under the conditions of this study, it was observed that the two welding methods analyzed were reliable for joining metallic superstructures without affecting their final fit.

Prevalencia de cristales de colesterol en granulomas perirradiculares de origen endodóntico / Prevalence of cholesterol crystals in periradicular granulomas of endodontic origin

Resumen Objetivo Comparar dos procedimientos de soldadura convencionales empleando una aleación de Cr-Co, para conectar barras coladas seccionadas a ser fijadas sobre implantes. Materiales y métodos A partir de un modelo maestro que representa un maxilar desdentado con cuatro implantes, se confeccionaron veinte (n=20) probetas seccionadas en tres partes. Se conformaron dos grupos, cada uno con diez (n=10) ejemplares. Una vez acondicionadas, fueron atornilladas al modelo maestro. Su desajuste inicial se analizó utilizando una lupa estereoscópica, con una cámara incorporada y un software. Las partes fueron soldadas empleando un procedimiento diferente para cada grupo. Las correspondientes al Grupo I se invistieron en un block refractario a base de sílico-fosfato. Las del Grupo II se montaron en una estructura metálica Clever Spider. El desajuste fue mensurado y los resultados procesados estadísticamente. El nivel de significación fue establecido en p<0,05. Resultados El Grupo I tuvo un desajuste inicial de 97,30±13,81μm y el Grupo II de 98,53±11,24μm. Luego de la soldadura, el Grupo I registró 98,53±17,17μm, 1,23μm mayor respecto al inicial. En el Grupo II se observó 103,13±17,61μm, 4,60μm por encima del original. Se analizaron mediante prueba t de Student; en ambos casos el resultado fue de p>0,05. Al comparar entre sí los grupos I y II, por medio de la prueba t y de comprobación no paramétrica de Mann-Whitney, se observaron diferencias no significativas, p=0,41 y p=0,38 respectivamente. Conclusiones Bajo las condiciones de este estudio, se observó que los dos métodos de soldadura analizados fueron confiables para unir supraestructurasos metálicas sin que se afecte su ajuste final.

Abstract Aim Compare two conventional welding procedures using a Cr-Co alloy, to connect sectioned cast bars to be fixed on implants. Materials and methods From a master model representing a toothless jaw with four implants, twenty (n=20) specimens sectioned into three parts were made. Two groups were formed, each with ten (n=10) specimens. Once conditioned, they were screwed to the master model. Its initial mismatch was analyzed using a stereoscopic magnifier, with a built-in camera and a software. The parts were welded using a different procedure for each group. Those corresponding to Group I were invested in a refractory block based on silyl-phosphate. Those of Group II were mounted on a Clever Spider metal structure. The mismatch was measured, and the results processed statistically. The level of significance was established at p<0.05. Results Group I had an initial mismatch of 97.30 ±13.81μm, and Group II of 98.53±11.24μm. After welding, Group I registered 98.53±17.17μm, 1.23μm higher than the initial one. In Group II, 103.13±17.61μm was observed, 4.60μm above the original. They were analyzed using Student's t test; in both cases the result was p>0.05. When comparing groups I and II, using the t-test and the Mann-Whitney nonparametric verification, non-significant differences were observed, p=0.41 and p=0.38 respectively. Conclusions Under the conditions of this study, it was observed that the two welding methods analyzed were reliable for joining metallic superstructures without affecting their final fit.

Estudio in vitro del ajuste de supraestructuras pasivadas sobre implantes múltiples / In vitro study of the adjustment of passivated suprastructures on multiple implants

Objetivo: Comparar dos procedimientos de soldadura convencionales empleando una aleación de Cr-Co, para co- nectar barras coladas seccionadas a ser fijadas sobre implantes. Materiales y métodos: A partir de un modelo maes- tro que representa un maxilar desdentado con cuatro implan- tes, se confeccionaron veinte (n=20) probetas seccionadas en tres partes. Se conformaron dos grupos, cada uno con diez (n=10) ejemplares. Una vez acondicionadas, fueron atornilla- das al modelo maestro. Su desajuste inicial se analizó utili- zando una lupa estereoscópica, con una cámara incorporada y un software. Las partes fueron soldadas empleando un pro- cedimiento diferente para cada grupo. Las correspondientes al Grupo I se invistieron en un block refractario a base de sílico-fosfato. Las del Grupo II se montaron en una estructu- ra metálica Clever Spider. El desajuste fue mensurado y los resultados procesados estadísticamente. El nivel de significa- ción fue establecido en p<0,05. Resultados: El Grupo I tuvo un desajuste inicial de 97,30±13,81µm y el Grupo II de 98,53±11,24µm. Luego de la soldadura, el Grupo I registró 98,53±17,17µm, 1,23µm mayor respecto al inicial. En el Grupo II se observó 103,13±17,61µm, 4,60µm por encima del original. Se analizaron mediante prue- ba t de Student; en ambos casos el resultado fue de p>0,05. Al comparar entre sí los grupos I y II, por medio de la prueba t y de comprobación no paramétrica de Mann-Whitney, se ob- servaron diferencias no significativas, p=0,41 y p=0,38 res- pectivamente (AU)

Aim: Compare two conventional welding procedures us- ing a Cr-Co alloy, to connect sectioned cast bars to be fixed on implants. Materials and methods: From a master model representing a toothless jaw with four implants, twenty (n=20) specimens sectioned into three parts were made. Two groups were formed, each with ten (n=10) specimens. Once conditioned, they were screwed to the master mod- el. Its initial mismatch was analyzed using a stereoscop- ic magnifier, with a built-in camera and a software. The parts were welded using a different procedure for each group. Those corresponding to Group I were invested in a refractory block based on silyl-phosphate. Those of Group II were mounted on a Clever Spider metal structure. The mismatch was measured, and the results processed statisti- cally. The level of significance was established at p<0.05. Results: Group I had an initial mismatch of 97.30 ±13.81µm, and Group II of 98.53±11.24µm. After welding, Group I registered 98.53±17.17µm, 1.23µm higher than the initial one. In Group II, 103.13±17.61µm was observed, 4.60µm above the original. They were analyzed using Stu- dent's t test; in both cases the result was p>0.05. When com- paring groups I and II, using the t-test and the Mann-Whitney nonparametric verification, non-significant differences were observed, p=0.41 and p=0.38 respectively. Conclusions: Under the conditions of this study, it was ob- served that the two welding methods analyzed were reliable for joining metallic superstructures without affecting their final fit (AU)

Influence of dental implant/mini-implant design on stress distribution in overdentures: a systematic review.

PURPOSE: Critically evaluate the existing literature and answer the question, "Does the dental implant/mini-implant design influence the stress distribution in prosthetic overdentures according to finite element analysis?". METHODS: This systematic review was registered in the Open Science Framework (osf.io/2bquj) and followed the PRISMA protocols. The custom search strategy was applied to 4 databases. In vitro experimental studies that evaluated the influence of dental implant/mini-implant design on stress distribution in overdentures by FEM, without time and language restrictions, were included. The selection process was carried out in two stages by two reviewers independently. Risk of bias analysis was performed by a checklist of important parameters. RESULTS: Sixty articles were evaluated by their title and abstract, four were selected for full reading, three were relevant, and nine were included by additional search. The 12 studies have a low risk of bias. The meta-analysis could not be performed due to the heterogeneity of the data (implant type, design variation, load intensity, and direction). CONCLUSION: It can be inferred from the evaluated literature that design modifications influence the stress distribution, but as the FEM presents limitations inherent to the in vitro study, clinical trials are necessary to infer the effectiveness of the modifications. It should be noted that there is no consensus on which is the best thread design and that implants with a very narrow diameter are subject to the highest stress concentration.

Analysis of stress/strain distribution in dental mini-implants manufactured by additive manufacturing and machining.

The study aimed to analyze the stress/strain distribution of new designs of mini-implants manufactured by machining and additive manufacturing. Four designs were evaluated (Ø2.0 mm × 10 mm): Intra-lock, helical, threaded machined (MN threaded) and threaded by additive manufacturing (AM threaded). Analysis of stress was performed through photoelastic analysis (100 N axial/oblique loads) and analysis of strain by digital image correlation (DIC) (250 N axial/100 N oblique load). Data distribution was verified using the Shapiro-Wilk test and a significance level of 5% was adopted. Quantitative data were analyzed using the non-parametric Kruskal-Wallis test. In photoelastic analysis, the Intra-lock mini-implant showed the highest stresses in the cervical (104 kPa), middle (108 kPa), and apical (212 kPa) thirds. Higher stresses were observed in the oblique loading situation for all designs. For DIC analysis, axial loading, a significant difference was observed for the AM Threaded mini-implants about the other designs in the cervical third (p = .04), with the highest strain value 47 µÎµ [10; 76]. In oblique loading, a significant difference between the mini-implants was observed in the middle and apical thirds, with higher strains for the AM threaded design -185 µÎµ [-173; 162] (p = .009) and 242 µÎµ [87; 372] (p = .013), respectively. In general, the influence of different mini-implant designs and the additive manufacturing method on the stress/strain was observed, in the photoelastic and DIC analysis. The evaluated designs demonstrated a lower concentration of stress/strain in the cervical region compared to the apical region, and higher stress/strain in situations of oblique load compared with axial load.

Reasons for the fatigue of ball attachments and their O-rings: A systematic review.

The ball attachments and their O-rings used for the retention and stabilization of overdentures showed a decrease in retention as the number of cycles increased. This fact resulted in a decrease in the retention of the prosthesis. The purpose of this study was to evaluate the fatigue resistance of ball attachments through a systematic review. An electronic search was performed using the Cochrane Library, LILACS, PubMed, ScienceDirect, and Web of Science databases. The search was conducted based on the PICOS framework. The inclusion criteria involved in the search comprised research articles written in English and published between the years 2000 and 2020. In the final selection, 18 articles were included in the review. Most of these studies performed the fatigue retention tests using parallel implants without angles. However, some studies used different angles to analyze the fatigue retention values. With the passage of time, the wear results in deformation and, as a consequence, a decrease in the retention of most attachments, leading to treatment failure. The main factor to be considered is the loss of retention of these components and their low durability. The loss of retention is due to large extent to the materials used to manufacture the attachments and O-rings, the size and angulation of the implants, and the length of the prosthesis. Future research is needed to further elucidate the reasons for the failure of the attachments.

Willingness to accept or refuse mandibular implant overdenture treatment: A prospective study on edentulous enrolled in a clinical trial.

BACKGROUND: Several complete denture wearers have major complaints and may be benefitted from implant treatment. However, the factors that shape the demand for and utilization of implants need further investigation. OBJECTIVE: The aim was to evaluate edentulous patient's willingness to accept or refuse the offer and provision of implant-retained treatment. METHODS: As part of a clinical trial, edentulous subjects were offered a mandibular overdenture retained by four mini-implants opposing a conventional maxillary denture. Treatment was offered without any financial costs for the patients. Patients' level of interest in receiving treatment was assessed using a 5-point Likert scale, and they were asked to respond to a list of reasons that led to their decision to accept or refuse implants. Those who refused implants received conventional prosthodontic interventions as required, and those who accepted implant treatment underwent surgical planning and implant placement. RESULTS: Of 175 eligible subjects, 147 accepted the offer of treatment and were invited to take part in the study (69.4% women, mean age 67.4 ± 10.0 years). Overall, 111 patients (75.5%) expressed a positive intention to undergo implant treatment at the initial contact. Implant treatment was performed for 56.3% (9/16) of those who answered 'probably yes' about their level of interest in implant treatment on the Likert scale, and 69.6% (64/92) of 'certainly yes' (p < .001). Older subjects were less likely to receive implants (OR = 0.93; p = .036), whilst those with a positive intention towards implants (OR = 3.15; p = .001), those previously treated by the dental team (OR = 7.89; p < .001), and who actively demanded implants (OR = 18.1; p < .001) were more likely to accept treatment. Improved chewing was the most common reason for accepting implants, whilst fear of surgery was the most reported reason for refusal. CONCLUSION: Refusal of implants was high among edentate patients even when financial costs were removed. Patients' initial attitude towards acceptance is a key factor in the demand for and uptake of implant therapy.

Prosthodontic outcomes of mandibular overdenture treatment with one or two implants: 4-year results of a randomized clinical trial.

OBJECTIVE: To assess the incidence of prosthodontic maintenance events and complications during 4 years of follow-up after mandibular overdenture treatment with one or two implants. METHODS: Participants received one or two implants inserted in the midline (1-IOD group) or the lateral incisor-canine area bilaterally (2-IOD group). Implants were loaded with an early loading protocol after 3 weeks. Programmed recall visits were scheduled at the 6-, 12-, 36-, and 48-month follow-ups and nonprogrammed visits in case of prosthodontic complaints. The type of maintenance was registered, and the final treatment outcome was classified as successful, surviving, unknown, dead, repair, or retreatment. RESULTS: Forty-seven participants, mean age 65.4 ± 8.6, 74.5% female, were included (1-IOD = 23; 2-IOD = 24) and 44 completed the 4-year follow-up. A total of 159 prosthodontic maintenance events occurred and 89 in unscheduled visits. The most common event was the need for minor modifications of the denture base due to sore spots in the oral mucosa (n = 56 in 31 patients), matrix activation (n = 54 in 34 patients), and overdenture fracture (n = 25 in 18 patients). A "successful" or "surviving" outcome could be attributed to 57.5% of cases, whereas 38.3% needed repair. No significant differences in the incidence of prosthodontic events or treatment outcomes were found between the two groups. CONCLUSIONS: Findings show that 1-IODs perform similar to 2-IODs when considering the incidence of fractures and the need for prosthodontic maintenance, including adjustments of the overdenture and the attachment system.

Mandibular bone characteristics, drilling protocols, and final insertion torque for titanium-zirconium mini-implants for overdentures: A cross-sectional analysis.

OBJECTIVE: The aim of this study was to assess the final insertion torque values achieved using site-specific drilling protocols for a novel mini implant system for removable complete overdentures. Anatomical and technical factors influencing final insertion torque were recorded and analyzed. MATERIAL AND METHODS: Participants were randomized to two surgical protocol groups (flapped or flapless) and all received four mini implants (Straumann® mini implant system; Straumann AG) in the anterior mandible, using a 1.6 mm needle drill and a 2.2 mm pilot drill for the implant bed site preparation. The final insertion torque was recorded as the main outcome variable during surgery. Bone type, radiographical bone density, ridge form, implant length, and the drilling protocol were considered as independent variables. Descriptive statistics, generalized estimating equations (GEE) regression, and heatmap charts were used for data analyses. RESULTS: A total of 296 mini implants were placed in 74 patients (mean age = 64.1 ± 8.0; 64.9% female) using flapless (n = 37) or flapped (n = 37) surgeries. Mean final insertion torque was 55.8 ± 18.4 Ncm (10.5% > 35 Ncm, 48.9% between 35 and 65 Ncm, and 40.6% > 65 Ncm). The needle drill was used in only 43.9% of the implant bed sites. Higher final torque values were observed for higher bone densities (bone type I > II > III, and D1-D2 > D3-D4), highly resorbed ridge forms (5-6 > 3-4), flapped surgeries, and male patients. However, regression models showed that the likelihood of achieving optimal insertion torque (≥35 and ≤65 Ncm) was higher for females (OR = 2.14; 95%CI = 1.14-4.01; p = 0.018), ridge forms 3-4 (OR = 2.87; 95%CI = 1.05-7.85; p = 0.040), and flapless surgeries (OR = 1.96; 95%CI = 1.09-3.51; p = 0.024). CONCLUSIONS: Sufficient primary stability for immediate loading was achieved for the majority of the mini implants placed. Surgical implant bed preparation should be site-specific to achieve optimal primary stability for immediate loading while avoiding excessive insertion torque.

Factors influencing retention and durability of attachments for overdentures - adverse effects of cleansings, pH, and temperature: A systematic review.

Aim: The objective of this systematic review is to show the current state of the art on which type of attachment loses retention the most and has reduced durability and which factor causes these problems the most. Material and methods: This review followed the Preferred Reporting Items for Systematic Review and MetaAnalysis (PRISMA) guidelines and it was registered with the Open Science Framework (OSF) (osf.io/2e3q5). The databases used for the electronic search of articles were Pubmed, Science Direct, Embase, and Scopus. Articles were selected by 2 independent reviewers according to the inclusion criteria. The risk of bias was analyzed by using the Joanna Briggs Institute (JBI) adapted quasi-experimental study evaluation tool. Results: The studies included in this review indicate that the use of cleansing solutions, high temperatures, and a more acidic pH decrease the durability of the attachments, mainly due to the loss of retention that occurs in different models and materials of the attachments, which requires their replacement in a shorter period. Conclusion: Of all the factors studied, the cleansing solutions proved to be the factor that most altered attachment retention. Different saliva compositions did not influence retention values. Aging changes retention values for attachments, mostly with loss of values.

Preparation of ICD and overdenture in patients with Cushing's Syndrome: five-year follow-up / Preparo de PTI e overdenture em pacientes com Síndrome de Cushing: cinco anos de acompanhamento

The aim of this study is to report a clinical case of a patient with Cushing's syndrome, low self-esteem and need for oral rehabilitation. A 50-year-old female patient with hypercortisolism sought care at School of Dentistry of the Federal University of Minas Gerais. During anamnesis, the patient reported painful symptoms and mobility of the upper and lower teeth. On clinical examination, absence of many teeth were observed, periodontal disease and caries lesions. After discussion of the case, the planning involved the extraction of all teeth, and the preparation of Maxillary Immediate Complete Dentures (ICD's) and Immediate Mandibular Implant-retained Overdenture (IMIO). The treatment proposed allowed the restored aesthetics, phonetics and chewing(AU)

O objetivo desse estudo é relatar um caso clínico de uma paciente com síndrome de Cushing, baixa autoestima e necessidade de reabilitação oral. Paciente do sexo feminino, 50 anos de idade e com hipercortisolismo, procurou atendimento na Faculdade de Odontologia da Universidade Federal de Minas Gerais. Durante a anamnese, a paciente relatou sintomas dolorosos e mobilidade dos dentes superiores e inferiores. No exame clínico, foi observada a ausência de muitos dentes, doença periodontal e lesões cariosas. Após a discussão do caso, o planejamento envolveu a extração de todos os dentes, e o preparo de Prótese Total Imediata maxilar (PTI), e Overdenture Implantorretida Imediata mandibular. O tratamento proposto permitiu que restaurasse a estética, fonética e mastigação(AU)

Sobredentadura parcial como alternativa de tratamiento en paciente con secuela periodontal. Reporte de caso / Partial overdenture as an alternative treatment in patients with periodontal sequelae. A case report

La rehabilitación de pacientes desdentados parciales periodontalmente comprometidos es un desafío a nivel protésico. Esto se debe a que la condición de los dientes pilares no siempre es la adecuada, viéndose afectada la proporción corono-radicular por las secuelas de una enfermedad periodontal. Es en estas situaciones límite donde el uso de implantes óseo-integrados acompañado de ataches resilientes mejora la retención de una prótesis parcial removible convencional, disminuyendo el riesgo de sobrecarga en los dientes remanentes. En este reporte de caso se presenta una rehabilitación integral, resuelto con una sobredentadura parcial maxilar sin cobertura palatina sobre pilares Locator®, minimizando la carga en los dientes remanentes del grupo II con secuelas periodontales; y una rehabilitación del arco mandibular con operatoria directa, indirecta y prótesis fija, recuperando funcionalidad, soporte oclusal y manteniendo los dientes remanentes en el sector anterior.

Rehabilitation of periodontally compromised partially edentulous patients has always been a challenge at the prosthetic level, because the condition of the remaining teeth is not always adequate and the crown-root ratio is often affected by the sequelae of periodontal disease. In these borderline situations, the use of osseointegrated implants accompanied by resilient attachments improves the retention of a conventional removable partial denture, reducing the risk of overloading the remaining teeth. This case report presents a comprehensive rehabilitation, resolved with a maxillary partial overdenture without palatal coverage on Locator® abutments, minimizing the load on the remaining pieces of group II with periodontal sequelae; and a rehabilitation of the mandibular arch with direct, indirect and fixed prosthesis. In this way, it was possible to recover functionality, occlusal support and keep the remaining teeth in the front part of the maxilla.

A 3-year prospective cohort on the incidence of prosthodontic complications associated with three implant treatment options for the edentulous mandible.

OBJECTIVE: This prospective study assessed the number and reasons for post-treatment visits due to prosthodontic complications in patients treated with three types of implant treatment for the edentulous mandible. METHODS: Study groups comprised patients treated with single-implant overdenture (G-I; n = 11), 2-implant overdenture (G-II; n = 13), and 4-implant fixed prosthesis (G-III; n = 13). Programmed recall visits occurred at the 6-, 12- and 36-month follow-ups. The management of prosthodontic complications occurred continuously in unscheduled appointments. Data analysis included calculation of incidence rates, chi-square and Kruskal-Wallis tests, and Poisson regression with robust error variance to model the occurrence of visits due to prosthodontic complications. RESULTS: There were 89 unscheduled appointments during the entire follow-up period, ranging from 0 to 7 (mean = 2.41; SD = 2.2) per patient. No between-group differences were found regarding the frequency of unscheduled visits. However, the duration of the appointments (scheduled and unscheduled) was significantly higher for G-III (p < .001). The length of follow-up was the only predictor of the number of post-insertion visits (p = .004). The frequency of prosthodontic events was higher for G-I and G-II compared to G-III (p < .001). Nearly half of the events in G-I and G-II were matrix replacements, and artificial teeth fracture was more frequent in G-III. CONCLUSIONS: All patients were at risk of post-delivery prosthodontic complications and required regular recall visits to achieve satisfactory function and to prevent further problems. Overdentures required higher rates of maintenance visits, particularly for replacement of the retentive inserts, while fixed implant prostheses required longer clinical times for management of complications when compared to overdentures.

Tratamiento protésico con sobredentadura en un anciano / Prosthetic treatment with overdenture in an elderly

Se describe el caso clínico de un anciano de 63 años de edad, con color de la piel mestizo y buena salud general, quien acudió a consulta de Prótesis Dental en la Clínica Estomatológica Provincial Docente Mártires del Moncada de Santiago de Cuba porque se encontraba afectado estéticamente y, además, deseaba preservar sus dientes remanentes; refirió que no había recibido tratamiento protésico previo. Luego de efectuar exámenes bucodental y complementarios, así como otros procedimientos odontológicos, se decidió rehabilitar con sobredentadura para conservar los dientes pilares, restablecer las funciones perdidas y mejorar la estética. El paciente fue rehabilitado estética y funcionalmente y mostró una evolución satisfactoria.

The case report of a half blood 63 years elderly with good general health, who visited the Dental Prosthesis Service in the Mártires del Moncada Teaching Provincial Estomatological Clinic in Santiago de Cuba is described, as he was esthetically affected and, he wished to preserve his remanent teeth; he informed that he had not received any previous prosthetic treatment. After making oral and dental exploration and other exams, as well as other odontological procedures, it was decided to rehabilitate him with overdentures to preserve the abutment teeth, to reestablish the lost functions and to improve esthetics. The patient was rehabilitated esthetically and functionally and he showed a satisfactory clinical course.