Implant-supported overdenture with horizontal insertion for treating the edentulous atrophic maxilla: A case series.

STATEMENT OF PROBLEM: Rehabilitation of edentulous patients with severe maxillary atrophy is a clinical challenge. Although several treatment options are available, the implant-supported overdenture has been widely advocated. However vertical insertion implant-supported overdentures have drawbacks, including wear, aging, and the continuous maintenance of retention systems. Whether an implant-supported overdenture with a horizontal insertion pathway can overcome these problems is unclear. PURPOSE: The purpose of this observational study was to determine the clinical and biological behavior of a new type of implant-supported overdenture with a horizontal insertion pathway over a mean clinical follow-up period of 6 years. MATERIAL AND METHODS: Ten study participants with an atrophic maxilla underwent rehabilitation with horizontal overdentures supported by 6 implants. Follow-up visits were scheduled at 3 months, 6 months, and annually thereafter. The variables analyzed were implant and prosthetic survival, peri-implant tissue behavior, mechanical complications, and patient satisfaction. RESULTS: The follow-up period ranged from 5 to 8 years, mean ±standard deviation 6.3 ±1.2 years. A total of 60 implants and 10 horizontal overdentures were placed. The clinical survival of the implants was 98.3% (mean peri-implant bone loss, 1.3 ±0.4 mm) and was 80% of the prostheses. Overall, mean patient satisfaction as assessed with a visual analog scale was 7.4, with 8.5 for esthetics and 9.5 for function. CONCLUSIONS: The horizontal implant-supported overdenture provided a functional alternative to conventional prostheses.

A novel, fully digital approach to quantifying volume gain after soft tissue graft surgery. A pilot study.

OBJECTIVE: Measuring soft tissue thickness after mucogingival surgery has traditionally been performed by means of a calibrated transgingival probe. The main aim of this study was to apply a non-invasive technique based on digital images formatted as Standard Tessellation Language (STL) files to quantify soft tissue volume after connective tissue grafting. CLINICAL INNOVATION REPORT: Ten patients who presented Cairo Class I gingival recession were selected for connective tissue grafting using the tunnel technique. In all patients, the initial position of the gingiva and quantity of keratinized tissue were recorded, and gingival recession was scanned with an intra-oral scanner. Six months after surgery, the same intra-oral parameters were recorded and compared with the initial registers using digital volumetric analysis software. RESULTS: Complete root coverage was obtained in most patients (90%), mean coverage being of 2.70 mm with a mean increase in volume of 115.49 mm3 in the treated areas. No pattern was identified that indicated a statistically significant relation between gingival recession and coverage volume in mm3 . CONCLUSIONS: Digital processing of pre- and post-treatment images makes it possible to measure the volume of tissue gained after tissue graft surgery simply and non-invasively. The technique is an objective and reproducible method for measuring soft tissue thickness.

Implant-Supported Fixed Partial Dentures with Posterior Cantilevers: In Vitro Study of Mechanical Behavior.

Rehabilitation with dental implants is not always possible due to the lack of bone quality or quantity, in many cases due to bone atrophy or the morbidity of regenerative treatments. We find ourselves in situations of performing dental prostheses with cantilevers in order to rehabilitate our patients, thus simplifying the treatment. The aim of this study was to analyze the mechanical behavior of four types of fixed partial dentures with posterior cantilevers on two dental implants (convergent collar and transmucosal internal connection) through an in vitro study (compressive loading and cyclic loading). This study comprised four groups (n = 76): in Group 1, the prosthesis was screwed directly to the implant platform (DS; n = 19); in Group 2, the prosthesis was screwed to the telescopic interface on the implant head (INS; n = 19); in Group 3, the prosthesis was cemented to the telescopic abutment (INC; n = 19); and in Group 4, the prosthesis was cemented to the abutment (DC; n = 19). The sets were subjected to a cyclic loading test (80 N load for 240,000 cycles) and compressive loading test (100 KN load at a displacement rate of 0.5 mm/min), applying the load until failure occurred to any of the components at the abutment-prosthesis-implant interface. Subsequently, an optical microscopy analysis was performed to obtain more data on what had occurred in each group. Results: Group 1 (direct screw-retained prosthesis, DS) obtained the highest mean strength value of 663.5 ± 196.0 N. The other three groups were very homogeneous: 428.4 ± 63.1 N for Group 2 (INS), 486.7 ± 67.8 N for Group 3 (INC), and 458.9 ± 38.9 N for Group 4 (DC). The mean strength was significantly dependent on the type of connection (p < 0.001), and this difference was similar for all of the test conditions (cyclic and compressive loading) (p = 0.689). Implant-borne prostheses with convergent collars and transmucosal internal connections with posterior cantilevers screwed directly to the implant connection are a good solution in cases where implant placement cannot avoid extensions.

Microtensile Bond Strength of CAD-CAM Restorative Dental Material Blocks to Resin Cement: An In Vitro Study.

INTRODUCTION: Today's dentistry frequently employs bonded partial restorations, which are usually fabricated in ceramic materials. In the last decade, hybrid materials have emerged that attempt to combine the properties of composites and ceramics. OBJECTIVES: To evaluate in vitro, by means of a microtensile test, the bond strength between CAD-CAM restorative materials and the cement recommended by their manufacturer. MATERIAL AND METHOD: From blocks of CAD-CAM restorative material bonded to composite blocks (Filtek 500®), beams with a bonding area of approximately 1 mm2 were made and divided into four groups: EMAX (IPS e.max CAD® lithium disilicate), VE (VITA Enamic® polymer-infiltrated ceramic matrix), LUA (Lava Ultimate® nano-ceramic resin with sandblasting protocol) and LUS (Lava Ultimate® nano-ceramic resin with silica coating protocol). In each group, perimeter (external) or central (internal) beams were differentiated according to the position in the block. The samples were tested on the LMT 100® microtensile machine. Using optical microscopy, the fractures were categorized as adhesive or cohesive (of the restorative material or composite), and the data were analysed with parametric tests (ANOVA). RESULTS: The LUS group had the highest results (42 ± 20 MPa), followed by the LUA group (38 ± 18 MPa). EMAX had a mean of 34 ± 16 MPa, and VE was the lowest in this study (30 ± 17 MPa). In all groups, the central beams performed better than the perimeter beams. Both EMAX and VE had the most adhesive fractures, while LUA and LUS had a predominance of cohesive fractures. CONCLUSIONS: Lava Ultimate® nanoceramic resin with the silica coating protocol obtains the best bond strength values.

The Influence of Keratinized Mucosa on the Nonsurgical Therapeutic Treatment of Peri-Implantitis.

OBJECTIVE: The main objective of this study aimed to evaluate the response to treatment in implants with peri-implantitis regarding the presence or absence of keratinized mucosa. MATERIALS AND METHODS: One hundred implants with peri-implantitis were treated non-surgically at the Prosthodontics and Occlusion Teaching Unit of the University of Valencia. Records were registered at day zero (recession, bleeding on probing, suppuration, probing depth, bone loss and plaque index), at 1, 3 and 6 months. RESULTS: In both groups, a slight increase in recession and disappearance of suppuration took place, and no bone loss was observed during the following 6 months. However, after an initial reduction, probing depth, bleeding on probing and plaque index increased again in the group without keratinized mucosa (KM). CONCLUSIONS: Implants with KM presented better results after non-surgical treatment as well as in their medium-term evolution, although it would be advisable to increase the number of samples in order to achieve greater scientific evidence and standardization in the treatment protocol. CLINICAL RELEVANCE: The role of keratinized mucosa in the development of peri-implantitis has been mentioned in many publications, but less has been emphasized regarding its influence on the success of the treatment of this pathology. The presence of keratinized mucosa has been found to play a key role in the evolution of the non-surgical treatment of peri-implantitis. The amount of keratinized mucosa should be considered in the treatment of peri-implantitis, as well as when planning connective tissue grafts accompanying the decontamination of implants in the absence of keratinized mucosa.

Comparative Study by Systematic Review and Meta-Analysis of the Peri-Implant Effect of Two Types of Platforms: Platform-Switching versus Conventional Platforms.

OBJECTIVE: The aim of the systematic review and meta-analysis carried out was to evaluate the effects of changing the prosthetic platform on peri-implant tissue after 1 year of prosthetic loading. MATERIAL AND METHODS: In November 2020, an electronic search was carried out in PubMed, EMBASE, Web of Science, and Scopus databases with the aim of obtaining all the randomized clinical trials that had been published in the preceding 10 years comparing the effects on the peri-implant tissue of implants with a prosthetic platform change and implants with a conventional platform for at least 1 year after prosthetic loading. Randomized model meta-analyses of the selected studies were performed to compare the results of the two implant groups in terms of vertical maintenance of bone level and increased probing depth. RESULTS: Nine studies were included, summing up a total of 475 implants with prosthetic platform exchange and 462 implants with a conventional platform. Implants with prosthetic platform exchange had less peri-implant bone loss than implants with a conventional platform (mean difference of 0.255 mm, statistically significant) but suffered a greater increase in probing depth (mean difference of 0.082 mm, not statistically significant). However, the probing depth from One Study Remove revealed a statistically significant increase of 0.190 mm in the prosthetic platform exchange group compared to the conventional platform group. CONCLUSION: Implants with platform switching suffer less peri-implant bone loss after 1 year of loading than implants with a conventional platform. Further long-term studies are required to observe how these differences vary over time.

Analysis of Peri-Implant Bone Loss with a Convergent Transmucosal Morphology: Retrospective Clinical Study.

OBJECTIVE: The aim of this study was to analyze the peri-implant bone loss of infracrestal, supracrestal, and crestal implants from the day of placement and up to 1 year of prosthetic loading. MATERIAL AND METHODS: A retrospective clinical study was carried out. The sample consisted of 30 implants placed on 30 patients. It was divided into three groups: infracrestal (n = 10), crestal (n = 10), and supracrestal (n = 10) implants. RESULTS: Following the statistical analysis, it was observed that, 4 months after implant placement, the mean values of total peri-implant bone loss were 0.04 mm in infracrestal implants, 0.26 mm in crestal implants, and 0.19 mm in supracrestal implants. At the end of one year of prosthetic loading, the peri-implant bone loss was 0.12 mm in infracrestal implants, 1.04 mm in crestal implants, and 0.27 mm in supracrestal implants. It was determined that peri-implant bone loss in crestal implants was significantly higher than in supracrestal implants, and these in turn were significantly higher than in infracrestal implants. CONCLUSIONS: The implants that obtained a better biological behavior on peri-implant bone tissue were the infracrestal implants with a converging transmucosal abutment.

Enamel Wear of Antagonist Tooth Caused by Dental Ceramics: Systematic Review and Meta-Analysis.

BACKGROUND: This systematic review and meta-analysis aimed to evaluate the wear of the antagonist tooth in ceramic restorations. MATERIAL AND METHODS: This study was carried out based on Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) recommendations; it was also registered in PROSPERO (register number: CRD42022316252). Three databases were consulted in the literature search, Embase, Scopus, and Web of Science. The citation searching was conducted by two researchers independently. The clinical studies that evaluated wear in antagonist teeth concerning ceramic restoration were included. Twelve articles were selected after eliminating duplicates ones and applying the inclusion criteria, and two were chosen through citation. Fourteen articles were considered for the qualitative and quantitative analysis (meta-regression and meta-analysis). RESULTS: The mean linear wear of the antagonist tooth in relation to feldspathic was 8.914 µm, for lithium disilicate it was 0.018 µm, and for zirconia it was 0.257 µm. The mean volumetric wear of the antagonist tooth in relation to feldspathic was 0.273 mm3, for hybrid ceramic it was 0.030 mm3, for lithium disilicate it was 0.018 mm3, and for zirconia it was 0.014 mm3. The mean natural tooth wear was 0.7974 µm per month. Tooth wear caused by zirconia at six months was 31.755 µm, at 12 months it was 24.648 µm, and at 24 months it was 20.662 µm. CONCLUSIONS: Feldspathic produces greater wear of the antagonist tooth from ceramic restorations linearly and volumetrically. In addition, zirconia generates the least wear that will decrease over time, and it will be equal to or less than the natural wear in the tooth.

Influence of the chemical composition of monolithic zirconia on its optical and mechanical properties. Systematic review and meta-regression.

PURPOSE: This systematic review set out to investigate the influence of chemical composition and specimen thickness of monolithic zirconia on its optical and mechanical properties. Meta-analysis and meta-regression analyzed the effects of variations in percentages of yttrium, aluminum, and specimen thickness of monolithic zirconia. STUDY SELECTION: The review followed recommendations put forward in the PRISMA checklist. An electronic search for relevant articles published up to October 2019 was conducted in the Pubmed, Cochrane, Scopus, Scielo, and Web of Science databases, with no language limits and articles published in the last 10 years. From 167 relevant articles; applying inclusion criteria based on the review's PICO question, 26 articles were selected for qualitative synthesis (systematic review) and 24 for quantitative synthesis (meta-analysis). Experimental in vitro studies published were selected and their quality was assessed using the modified Consort scale for in vitro studies of dental materials. RESULTS: The variables yttrium, aluminum and thickness were analyzed in random effects models, observing high heterogeneity (>75%), and finding statistically significant influences on the properties of monolithic zirconia (p<0.05). CONCLUSION: Within the review's limitations, it may be concluded that variations in the percentage of yttrium and aluminum influence the optical and mechanical properties of monolithic zirconia, making it more or less esthetic and resistant in relation to each variable. The clinical implications of these findings can help select the most appropriate type of zirconia to meet the different clinical needs when restoring different regions (posterior or anterior).

Correlation between Polysomnographic Parameters and Tridimensional Changes in the Upper Airway of Obstructive Sleep Apnea Patients Treated with Mandibular Advancement Devices.

BACKGROUND: The effectiveness of mandibular advancement devices has been solidly demonstrated in the past. They are considered a valid alternative treatment to continuous positive airway pressure for patients with obstructive sleep apnea. Nevertheless, the relationship between polysomnographic parameters and the increase in the volume of the upper airway in patients with obstructive sleep apnea syndrome has not been clearly established so far. This study aimed to determine the impact of these oral appliances upon the volume of the airway after the device titration phase and correlate it with the degree of mandibular advancement and the improvement of polysomnographic parameters. METHODS: All patients were diagnosed by polysomnography and were treated with a customized, titratable mandibular advancement device. Three-dimensional volumetric measurements were performed using cone beam computed tomography. RESULTS: The present study included 45 patients diagnosed with obstructive sleep apnea hypopnea syndrome (mild in 23 patients, moderate in 11 and severe in 11). Forty-four percent of the patients presented with an apnea hypopnea index <5/h at the end of treatment. The volume of the upper airway increased an average of 4.3 ± 5.9 cm3, this represents a percentage increase of 20.9%, which was significantly correlated with an apnea hypopnea index and a minimum oxygen saturation improvement. CONCLUSIONS: The mandibular advancement device used was found to be effective in improving polysomnographic parameters. Moreover, the oral appliance was able to significantly increase the tridimensional dimensions of the upper airway. Moreover, this finding was correlated with a reduction in the apnea hypopnea index (p = 0.007) and an increase on minimum oxygen saturation (p = 0.033).

Analysis of Predisposing Factors for Rapid Dental Calculus Formation.

BACKGROUND: Calculus accumulation varies widely between individuals. Dental calculus has been associated with the principal periodontal diseases. The aim of this study was to analyze individual characteristics, and salivary and microbiological parameters among patients considered to be rapid calculus formers and patients who form calculus slowly. METHODS: Individual characteristics were recorded in a sample of 74 patients (age, sex, smoking, periodontal diagnosis, and dental crowding), as well as salivary parameters (unstimulated saliva flow, pH, and biochemical analysis of saliva) and microbiological parameters (by means of semi-quantitative polymerase chain reaction (PCR) analysis). RESULTS: A statistically significant association (p = 0.002) was found between the rate of calculus formation and the diagnosis of periodontal disease. A greater presence of dental crowding was observed among the group of rapid calculus formers. Urea and phosphorus levels were higher among rapid calculus formers. Regarding microbiological parameters, differences were found in Streptococcus mutans, this being higher in the group of slow formers. CONCLUSIONS: Rapid calculus formation appears to be linked to patients diagnosed with more severe periodontal diseases. Rapid calculus-forming patients present more dental crowding and a lower proportion of S. mutans.

Wear in Antagonist Teeth Produced by Monolithic Zirconia Crowns: A Systematic Review and Meta-Analysis.

BACKGROUND: The aim of this systematic review and meta-analysis was to determine the wear sustained in the natural antagonist tooth in cases of full-coverage fixed-base prosthetic restorations or monolithic zirconia tooth-supported crowns, as well as to determine the wear in the restoration itself, both in the short- and medium-term and considering the factors that may influence wear. MATERIAL AND METHODS: A systematic literature review and meta-analysis, based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations, of clinical studies that evaluated wear in antagonist teeth in relation to fixed-prosthesis monolithic zirconia crowns. A total of 5 databases were consulted in the literature search: Pubmed-Medline, Cochrane, Scopus, Embase and Web of Science (WOS). After eliminating duplicated articles and applying the inclusion criteria, eight articles were selected for the qualitative analysis and four for the quantitative analysis. RESULTS: Mean maximum wear of the antagonist tooth in relation to monolithic zirconia crowns of magnitude 95.45 µm (CI at 95% 79.57-111.33) was observed. By using a meta-regression model (R2 = 0.92) the significant effect of time in maximum wear rate (p < 0.001) was observed, estimated at 6.13 µm per month (CI at 95% 3.99-8.27). Furthermore, monolithic zirconia crowns are subject to a mean maximum wear of 58.47 µm (CI 95% 45.44-71.50). By using a meta-regression model (R2 = 0.53) the significant effect of time in the maximum wear value was observed (p = 0.053), estimated at 3.40 µm per month (CI al 95% -0.05-6.85). CONCLUSIONS: Monolithic zirconia crowns lead to a progressive maximum wear of the antagonist tooth over time which is greater than the maximum wear sustained in the crown itself. It is not possible to establish an objective and quantitative objection in relation to natural enamel wear or metal-ceramic crowns.