Periodontal outcomes of anterior fixed partial dentures on teeth treated with the biologically oriented preparation technique: A 6-year prospective clinical trial.

STATEMENT OF PROBLEM: One of the most frequent complications in participants with fixed partial dentures (FPDs) is the apical migration of the gingival margin, which may be associated with factors such as fit, gingival margin location, or tooth preparation type. The prevalence of the complication in participants restored with FPDs prepared by using the biologically oriented preparation technique (BOPT) is unclear. PURPOSE: The purpose of this prospective clinical trial was to evaluate the clinical and biologic outcomes of FPDs on teeth prepared by using the BOPT, over a 6-year follow-up period. MATERIAL AND METHODS: Tooth-supported zirconia FPDs in the anterior region prepared by using the BOPT were evaluated. Each participant was monitored annually for 6 years by evaluating plaque index, probing depth, vestibular gingival thickness, and gingival margin stability. Biologic and/or mechanical complications were also recorded. Patient satisfaction was measured by using a visual analog scale (VAS). RESULTS: A total of 25 FPDs supported by 70 teeth in 24 participants were analyzed. Low plaque index values and stable probing depths were observed, whereas the gingival index was 0 for most of the teeth. Teeth treated by using the BOPT presented significant increase in gingival thickness, and the gingival margin was found to be stable in 100% of the treatments. FPD survival was 100%. CONCLUSION: Tooth supporting FPDs prepared by using the BOPT presented good periodontal health and gingival margin stability, without recession and with a 100% survival rate during a 6-year follow-up.

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.

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).

Periodontal Behavior and Patient Satisfaction of Anterior Teeth Restored with Single Zirconia Crowns Using a Biologically Oriented Preparation Technique: A 6-Year Prospective Clinical Study.

OBJECTIVES: The aim of this study was to analyze the behavior of the periodontal tissues around teeth in the anterior region when restored with zirconia single crowns, using a biologically oriented preparation technique (BOPT), over a 6-year follow-up. METHODS: The study investigated tooth-supported single crowns in the anterior region that were fabricated with a zirconia core and feldspathic ceramic covering, in 34 patients. Follow-up analysis took place annually for 6 years, assessing periodontal responses by evaluating the following variables: plaque index (PI); probing depth (PD); gingival index (GI); gingival thickness adjacent to the restoration; and stability of the gingival margin (MS). Any (biological and mechanical) complications were also recorded, as well as the patients' satisfaction with the treatment. RESULTS: After 6 years' follow-up, a low mean plaque index was obtained, probing depth was stable, and gingival thickness and margin stability had increased. Complications (biological and mechanical) did not present a statistically significant incidence and a crown survival rate of 97.2% was achieved. Patients' satisfaction obtained a mean VAS score of 9.04 under 10. CONCLUSION: Teeth that are prepared with BOPT in the anterior region present good periodontal behavior around the restored teeth, particularly in terms of the stability of the gingival margin and increased gingival thickness. Single crowns prepared with BOPT obtain an excellent clinical survival rate, as well as a high score in patients' satisfaction after 6 years.

Dimensional analysis of the upper airway in obstructive sleep apnoea syndrome patients treated with mandibular advancement device: A bi- and three-dimensional evaluation.

BACKGROUND: The efficiency of the mandibular advancement device (MAD) in patients with obstructive sleep apnoea syndrome (OSAS) has been demonstrated. Nevertheless, the behaviour of the upper airway once MAD is placed and titrated, and its correlation with the apnoea-hypopnoea index (AHI) is still under discussion. OBJECTIVES: To analyse the morphological changes of the upper airway through a bi- and three-dimensional study and correlate it with the polysomnographic variable, AHI. METHODS: Patients were recruited from two different hospitals for the treatment of OSAS with a custom-made MAD. A cone-beam computer tomography and a polysomnography were performed at baseline and once the MAD was titrated. RESULTS: A total of 41 patients completed the study. Treatment with MAD reduced the AHI from 22.5 ± 16.8 to 9.2 ± 11.6 (p ≤ .05). There was a significant increase of the total airway volume with MAD from 21.83 ± 7.05 cm3 to 24.19 ± 8.19 cm3 , at the expense of the oropharynx. Moreover, the correlation between the improvement of the AHI and the augmentation of the volume of the upper airway was not statistically significant. CONCLUSIONS: The oral device used in this prospective study increased the mean upper pharyngeal airway volume and significantly reduced the AHI. Future studies that measure the muscular tone are needed to completely understand the association between the AHI and the physiological and anatomical response of the upper airway.

Systematic review of chewing simulators: Reality and reproducibility of in vitro studies.

BACKGROUND: The aim of this systematic review was to analyze the types of human chewing simulator described in scientific literature. MATERIAL AND METHODS: An electronic search was conducted in the databases PubMed, Embase and Scopus. The search strategy included 10 search terms: "in vitro"; "dental materials"; "shear strength"; "fatigue fracture"; "bite force"; "prosthetic materials"; "chewing simulator"; "chewing machine"; "simulated mastication"; and "dental wear simulator." Two researchers worked independently to assess the titles and abstracts of the articles. The quality of the in vitro trials selected was evaluated by means of the Consolidated Standards of Reporting Trials scale. RESULTS: The electronic search identified 80 articles related to the topic of interest. After reading the full texts, ten works were selected. The articles focused mainly on the design of chewing simulators. Most of them were considered of moderate quality. Regarding the characteristics that an ideal chewing simulator should encompass, the devices described in articles varied greatly in terms of movement, periodontal ligament simulation, force sensors, and the materials tested. CONCLUSIONS: No chewing simulator offers all the characteristics necessary to reproduce human masticatory movements and forces under the humidity and pH conditions of the oral cavity. A simulator that encompasses all these characteristics would make it possible to standardize trials involving simulated mastication. Key words:In vitro, dental materials, dental wear simulator.

Histological study of human periodontal tissue following biologically oriented preparation technique (BOPT).

BACKGROUND: The aim of this study was to conduct histological analysis of a human tooth resected with the periodontal insertion apparatus intact following treatment using biologically oriented preparation technique (BOPT). MATERIAL AND METHODS: This descriptive histological dento-periodontal study used an anterior tooth extracted with the surrounding periodontal tissues intact, following prosthetic restoration with BOPT. The sample patient was recruited from among those attending the Department of Dental Medicine at the Faculty of Medicine and Dentistry, University of Valencia (Spain). Eight serial sections of the restored tooth were processed. The relative location and histological characteristics of the cemented prosthetic crown, the dental tissues of the tooth prepared by BOPT technique, and the periodontal tissues were analyzed. RESULTS: Structural analysis of the neoformed junctional epithelium showed that the number of layers decrease apically until there was a single row of cells perfectly adhered to the acellular cementum, and beneath the epithelium a connective tissue evidently free from inflammation. The tissues of the neoformed periodontium (gingival ligament, sulcular epithelium, junctional epithelium) presented histologic normality. CONCLUSIONS: Biologically oriented preparation technique is a reliable alternative to conventional horizontal finish lines. Key words:Vertical preparation, prosthetic cementoenamel junction (PCEJ), finish line, BOPT, crown.

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.

Fracture Resistance of New Metal-Free Materials Used for CAD-CAM Fabrication of Partial Posterior Restorations.

Background and Objectives: To evaluate in vitro the fracture resistance and fracture type of computer-aided design and computer-aided manufacturing (CAD-CAM) materials. Materials and Methods: Discs were fabricated (10 × 1.5 mm) from four test groups (N = 80; N = 20 per group): lithium disilicate (LDS) group (control group): IPS e.max CAD®; zirconium-reinforced lithium silicate (ZRLS) group: VITA SUPRINITY®; polymer-infiltrated ceramic networks (PICN) group: VITA ENAMIC®; resin nanoceramics (RNC) group: LAVA™ ULTIMATE. Each disc was cemented (following the manufacturers' instructions) onto previously prepared molar dentin. Samples underwent until fracture using a Shimadzu® test machine. The stress suffered by each material was calculated with the Hertzian model, and its behavior was analyzed using the Weibull modulus. Data were analyzed with ANOVA parametric statistical tests. Results: The LDS group obtained higher fracture resistance (4588.6 MPa), followed by the ZRLS group (4476.3 MPa) and PICN group (4014.2 MPa) without statistically significant differences (p < 0.05). Hybrid materials presented lower strength than ceramic materials, the RNC group obtaining the lowest values (3110 MPa) with significant difference (p < 0.001). Groups PICN and RNC showed greater occlusal wear on the restoration surface prior to star-shaped fracture on the surface, while other materials presented radial fracture patterns. Conclusion: The strength of CAD-CAM materials depended on their composition, lithium disilicate being stronger than hybrid materials.

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.

Influence of Biologically Oriented Preparation Technique on Peri-Implant Tissues; Prospective Randomized Clinical Trial with Three-Year Follow-Up. Part I: Hard Tissues.

PURPOSE: The objective of this prospective randomized clinical trial (RCT) was to analyze and compare the clinical behavior of three types of prosthesis supported by single implants in the posterior region after three years functional loading. MATERIALS AND METHODS: Seventy-five implants were divided into three groups according to the type of prosthetic restoration: screw-retained crown (Group GS); cemented crown without finishing line (biologically oriented preparation technique) (Group GBOPT); and conventional cemented crown with finishing line (Group GCC). The clinical behavior of each restoration type was analyzed after 3 years functional loading by analyzing radiographic peri-implant bone loss. RESULTS: GBOPT obtained the least bone loss (p < 0.01) in comparison with GS and GCC. CONCLUSIONS: Bone loss around implants is related to the type of prosthetic restoration it supports, whereby cemented BOPT crowns present less bone loss.

Fracture Resistance of Partial Indirect Restorations Made With CAD/CAM Technology. A Systematic Review and Meta-analysis.

BACKGROUND: The aim of this systematic review and meta-analysis was to determine the fracture resistance and survival rate of partial indirect restorations inlays, onlays, and overlays fabricated using computer-aided design and computer-aided manufacturing (CAD-CAM) technology from ceramics, composite resin, resin nanoceramic, or hybrid ceramic and to analyze the influence of proximal box elevation on fracture resistance. MATERIALS AND METHODS: This systematic review was based on guidelines proposed by the preferred reporting items for systematic reviews and meta-analyses (PRISMA). An electronic search was conducted in databases US National Library of Medicine National Institutes of Health (PubMed), Scopus, Web of Science (WOS), and Embase. In vitro trials published during the last 10 years were included in the review. RESULTS: Applying inclusion criteria based on the review's population, intervention, comparison, outcome (PICO) question, 13 articles were selected. Meta-analysis by restoration type estimated the fracture resistance of inlays to be 1923.45 Newtons (N); of onlays 1644 N and of overlays 1383.6 N. Meta-analysis by restoration material obtained an estimated fracture resistance for ceramic of 1529.5 N, for composite resin of 1600 Ne, for resin nanoceramic 2478.7 N, and hybrid ceramic 2108 N. CONCLUSIONS: Resin nanoceramic inlays present significantly higher fracture resistance values. Proximal box elevation does not exert any influence on the fracture resistance of indirect restorations.

Are Metal-Free Monolithic Crowns the Present of Prosthesis? Study of Mechanical Behaviour.

PURPOSE: To analyze in vitro the mechanical behavior of five types of complete coverage crowns fabricated from different materials. MATERIALS AND METHODS: Seventy-five full coverage crowns were divided into five groups according to material: Group I, metal core with feldspathic ceramic covering (MC- control group); Group II, zirconia core with feldspathic ceramic covering (CZ); Group III, tetragonal monolithic zirconia (TMZ); Group IV, cubic monolithic zirconia (CMZ); Group V, high molecular weight polymethyl methacrylate (PMMAG) doped with graphene nanoparticles. All crowns underwent in vitro fatiguing by dynamic loading in wet conditions to simulate the masticatory forces to which prosthodontic materials are subject in the oral medium. Lastly, fracture resistance was evaluated by static compression testing. RESULTS: The fracture resistance values obtained were as follows: Group MC, 2443.6 ± 238.6 N; Group CZ, 2095.4 ± 329.2 N; Group TMZ, 2494.6 ± 236.6 N; Group CMZ, 1523.6 ± 325.2 N; and Group PMMAG, 1708.9 ± 386.6 N. Group MC presented higher strength with statistically significant differences in comparison with Groups CZ (P = 0.002), CMZ (P < 0.001), and PMMAG (P < 0.001). Weibull distribution showed less probability of cumulative biomechanical failure in Groups MC and TMZ. CONCLUSIONS: Metal-ceramic and tetragonal zirconia showed high fracture resistance, while cubic zirconia and PMMA doped with graphene nanoparticles obtained lower values.

Assessment of the capacity of a pyrophosphate-based mouth rinse to inhibit the formation of supragingival dental calculus. A randomized double-blind placebo-controlled clinical trial

Background: This study aimed to analyze the efficacy of an anti-calculus mouth rinse and its possible adverse effects on the mucosa and teeth. Material and Methods: This randomized double-blind placebo-controlled clinical trial included 40 patients with treated and managed periodontal disease, all with a history of rapid calculus formation. Patients used a pyrophos-phate-based test mouth rinse (B) or a placebo (A). A range of parameters were measured for: saliva (saliva flow, pH and chemical composition); calculus (Volpe-Manhold [V-M] index, weight, and volume); adverse effects on mucosa and teeth; and the patients’ subjective perceptive of mouth rinse efficacy. Results: the test mouth rinse B produced reductions in urea, uric acid, and phosphorous, calcium, saliva flow, and increases in pH. V-M index and calculus weight decreased after using the test mouth rinse. Calculus volume decreased with both mouth rinses. No changes to the mucosa or teeth were observed. Patients perceived that the test mouth rinse was more effective

No disponible

Fracture resistance and the mode of failure produced in metal-free crowns cemented onto zirconia abutments in dental implants.

The purpose of the investigation was to analyze fracture resistance and mode of failure of zirconium oxide (zirconia) abutments placed on dental implants bearing crowns of different esthetic materials: zirconia, lithium disilicate (LDS), and nano-ceramic resin, for replacing single teeth in the anterior sector. Eighty implant-abutment-crown units were divided into four groups: Group T-MC (control): 20 metal-ceramic crowns cemented onto titanium abutments; Group Z-Z: 20 zirconia crowns on zirconia abutments; Group Z-LD: 20 lithium disilicate crowns on zirconia abutments; and Group Z-NCR: 20 nano-ceramic resin crowns on zirconia abutments. Specimens underwent a fatiguing process (dynamic loading and thermocycling), followed by static loading to evaluate mechanical fracture resistance, and the mode of failure produced. Mean fracture resistance values were: Control Group T-MC, 575.85±120.01 N; Group Z-Z 459.64±66.52 N; Group Z-LD, 531.77±34.10 N; and Group Z-NCR, 587.05±59.27 N. In Group T-MC, fracture occurred in the prosthetic fixing screw in 100% of specimens. In Group Z-Z, 80% of fractures occurred in the fixing screw, 15% in the abutment, and 5% in the abutment and crown. In Group Z-LD, 60% of fractures were produced in the fixing screw and 40% in the abutment. In Group Z-NCR, 70% of fractures were produced in the fixing screw and 30% in the abutment. All the abutments and crowns analyzed have the potential to withstand the physiological occlusal forces to which they would be subject in the anterior region. Lithium disilicate and nano-ceramic resin crowns cemented onto zirconia abutments are a good restoration alternative for single implants in the anterior sector.

Shear bond strength of debonded ceramic restorations re-cemented by means of a cleaning and retreatment protocol.

BACKGROUND: As there is no standard method for re-cementing debonded partial ceramic restorations, the aim of this study was to evaluate the use of a non-invasive thermal protocol for cleaning and retreatment, and to study its influence on shear bond strength. MATERIAL AND METHODS: Twenty ceramic samples (IPS e.max CAD®) were bonded to composite cement cylinders and underwent a shear bond strength test (G1, n=20). A second group was created (G2, n=20), representing debonded restorations. To simulate debonding, the samples were artificially contaminated with composite cement. After debonding, these underwent a thermal protocol to remove remaining adhesive. After rebonding to the composite cement cylinders, samples underwent the shear bond strength test. RESULTS: Median bond strengths for G1 and G2 were 7.28±3.23; 7.06±3.41 MPa, respectively, without significant difference between the groups (p=0.983). CONCLUSIONS: Debonded lithium disilicate glass-ceramic restorations should undergo a laboratory cleaning and retreatment protocol before being returned to the clinic for rebonding. Key words:Ceramic, adhesive debonding, shear bond strength, porcelain laminated veneers.

Periodontal and prosthetic outcomes on teeth prepared with biologically oriented preparation technique: a 4-year follow-up prospective clinical study.

PURPOSE: To evaluate the clinicaland biological behavior of full coverage restorations on teeth prepared without finish line during a 4-year follow-up. METHODS: This prospective study included 149 teeth treated using biologically oriented preparation technique (BOPT). The sample (149 teeth) was divided into two groups: Seventy four teeth restored with crowns, and 75 teeth supporting fixed partial dentures (FPD). Restorations were fabricated with zirconium oxide cores and ceramic coverings. Patients attended regular annual check-ups when probe depth, presence of inflammation with bleeding on probing, presence of plaque, gingival thickness, marginal stability, biological or mechanical complications, and the patient's level of satisfaction were registered over a 4-year follow-up. RESULTS: After the 4-year follow-up, 2.1% of teeth underwent increases in probing depth; 12% of the sample presented inflammation and bleeding on probing; 20% of the restored teeth presented plaque; gingival thickening increased a 32.5%; 98.6% of teeth presented marginal stability; the restoration survival rate was 96.6%, with 2% of biological complications and 1.4% of mechanical complications. General satisfaction score was 80.73. CONCLUSIONS: Restorations placed on teeth prepared using BOPT present good periodontal behavior, increase of gingival thickening, and marginal stability over a 4-year follow-up. High survival rates after 4 years show that the technique produces predictable outcomes. CLINICAL SIGNIFICANCE: The BOPT technique is a good treatment option in cases where replacement of an old restoration is required; presenting good periodontal behavior, gingival thickening, and marginal stability.

Influence of Biologically Oriented Preparation Technique on Peri-Implant Tissues; Prospective Randomized Clinical Trial with Three-Year Follow-Up. Part II: Soft Tissues.

Purpose: The objective of this prospective randomized clinical trial (RCT) was to analyze and compare the clinical behavior of three types of prosthesis supported by single implants in the posterior region after three years of functional loading. Materials and methods: Seventy-five implants were divided into three groups according to the type of prosthetic restoration: screw-retained crown (group GS); cemented crown without finishing line (biologically oriented preparation technique) (group GBOPT); and conventional cemented crown with finishing line (group GCC). After three years in function, clinical parameters (presence of keratinized mucosa, probing depths, bleeding on probing, and radiographic bone loss) were compared between the three experimental groups. The possible correlation between soft tissue clinical parameters and bone loss was also analyzed. Results: Statistical analysis found significant differences in clinical parameters between the different types of crown, with the cemented restoration without finishing line (BOPT) presenting fewer complications and better peri-implant health outcomes including: significantly different KMW data (mm), with significant differences between groups GBOPT and GCC (p < 0.001, Kruskal-Wallis test), with GBOPT obtaining larger quantities of keratinized mucosa (KM); statistically significant differences in probing depth (PD) values between groups GBOPT and GCC (p = 0.010, Kruskal-Wallis test); significant differences in bleeding on probing (BOP) between groups GBOPT and GCC (p = 0.018, Chi2 test) in favor of GBOPT. Conclusions: Soft tissue behavior around implants is related to the type of prosthetic restoration used, with cemented prostheses with BOPT presenting better peri-implant soft tissue behavior.

Comparative In Vitro Study of Implant-Supported Restorations: Implant-Abutment Complex With and Without Prosthetic Finishing Line.

PURPOSE: The aim of this study was to evaluate the mechanical behavior of implant-supported cemented restorations placed on two types of abutment design, with and without a prosthetic finish line, evaluating fracture resistance and the type of fracture produced in the abutment-crown complex. MATERIALS AND METHODS: Eighty zirconia restorations supported by tapered implants were divided into two groups: group I, with 40 zirconia crowns cemented onto individualized zirconia abutments with a chamfered finish line (1 mm deep); and group II, with 40 zirconia crowns cemented onto individualized zirconia abutments without a finish line. All specimens underwent thermocycling and dynamic loading before static load testing to evaluate their fracture resistance. RESULTS: Fracture resistance values (N) and the type of fracture were analyzed. The mean fracture resistance was 462.1 ± 66.3 N in group I and 343 ± 40 N in group II. In group I, fractures were produced in the prosthetic fixation screw; in group II, all mechanical failures were produced in the transepithelial abutment's cervical area. CONCLUSION: Group I specimens showed greater fracture resistance than group II. The fracture type in group I occurred in the prosthetic screw. Group II fractures occurred in the zirconium oxide abutment.

Effectiveness of a mandibular advancement device in obstructive sleep apnea patients: a prospective clinical trial.

PURPOSE: This study aimed to determine the effectiveness of a mandibular advancement device in a sample of obstructive sleep apnea syndrome patients by the evaluation of respiratory and neurophysiologic parameters and clinical symptoms. Second, the influence of certain predictor factors related with the patient and the intraoral device, were considered in the final response with this treatment option. METHODS: Forty-one patients constituted the final sample. Outcomes were measured using polysomnography, Epworth sleepiness scale and an analogue visual snoring scale, before treatment and once the device was properly titrated. RESULTS: Mean apnea-hypopnea index decreased from 22.5 ± 16.8 to 9.1 ± 11.6 (p ≤ 0.05), influencing only gender and Fujita index as predictor factors. The oxygen saturation, arousal index, percentages of sleep stages and sleep efficiency significantly improved with the mandibular advancement device (MAD) placement. The snoring index improved in absolute terms in 6.1 units and the excessive daytime sleepiness was reduced from 12.2 ± 4.7 to 8.5 ± 3.8 (p ≤ 0.00). CONCLUSIONS: The successful treatment rate with the MAD was 65.8%. The placement and posterior regulation of the intraoral appliance efficiently reduced the apnea-hypopnea index, improved the sleep quality and the clinical symptomatology associated. Obstructive sleep apnea syndrome is a highly prevalent disease. and dentists should be aware of the benefits enhanced by this prosthetic device, considered the first treatment option by certain physicians.