Implant-supported full-arch rehabilitation with immediate loading using two different digital impression techniques: a case report with 2-year follow-up.

Immediate full-arch loading is a highly complex and technique-sensitive procedure. Digital impression techniques aim to replace conventional analog systems to carry out dental treatments in a more predictive, safer, and less time-consuming way. This case report describes a patient with a guarded periodontal prognosis, who was rehabilitated with implant-supported fixed prostheses after full-mouth extractions. Immediate full-arch loading was performed by means of two digital impression systems: photogrammetric technology with PIC dental in the maxillary arch, and MedicalFit in the mandible. Immediate provisional prostheses in acrylic resin (polymethyl methacrylate) were milled and placed within 12 hours after implant placement surgeries. Both provisional structures fitted properly providing adequate esthetics and function. After the implant osseointegration period, final digital impressions were registered, and definitive zirconia full-arch implant-supported prostheses were delivered. The 24-month follow-up did not show biologic or mechanical complications.

Accuracy of Digital Dental Implants Impression Taking with Intraoral Scanners Compared with Conventional Impression Techniques: A Systematic Review of In Vitro Studies.

The aim of this systematic review was to evaluate the in vitro accuracy of dental implants impressions taken with intraoral scanner compared with impressions taken with conventional techniques. Two independent reviewers conducted a systematic electronic search in the PubMed, Web of Science and Scopus databases. Some of the employed key terms, combined with the help of Boolean operators, were: "dental implants", "impression accuracy", "digital impression" and "conventional impression". Publication dates ranged from the earliest article available until 31 July 2021. A total of 26 articles fulfilled the inclusion criteria: 14 studies simulated complete edentation (CE), nine partial edentation (PE) and only two simulated a single implant (SI); One study simulated both CE and SI. In cases of PE and SI, most of the studies analyzed found greater accuracy with conventional impression (CI), although digital impression (DI) was also considered adequate. For CE the findings were inconclusive as six studies found greater accuracy with DI, five found better accuracy with CI and four found no differences. According to the results of this systematic review, DI is a valid alternative to CI for implants in PE and SI, although CI appear to be more accurate. For CE the findings were inconclusive, so more studies are needed before DI can be recommended for all implant-supported restorations.

Digital Impression Taking for Maxillary Full-Arch Restoration With Immediate Loading: A Case Report.

The aim of this clinical report is to describe a maxillary full-arch implant supported restoration with immediate loading performed by means of an entirely digital work flow with photogrammetric system and intraoral scanning. A female patient with an edentulous maxillary arch attended the dental clinic seeking a maxillary fixed restoration. After treatment planning, 6 implants were placed using a surgical splint fabricated digitally by intraoral scanning of her previous removable prosthesis. Multiunit abutments were fitted, and 2 digital impressions were taken, one with a photogrammetric system for determining implant positions and the other with an intraoral scanner for soft tissue registration. The acrylic resin structure of the immediate prosthesis was milled and placed within 8 hours of implant surgery. This provisional structure fitted correctly and provided adequate esthetics and function. Radiographic and clinical follow-up after 24 months observed adequate implant evolution.

The key role of the dental practitioner in early diagnosis of periodontal Ehlers-Danlos syndromes: a rare case report of siblings.

Ehlers-Danlos syndromes (EDS) are a group of diverse hereditary connective tissue disorders. Various EDS subtypes present as different diseases. Periodontitis of early onset is a major criterion of periodontal EDS (pEDS). This article reports the clinical case of two siblings, young adults, who came to the clinic for diagnosis and treatment of periodontal disease. The patients had already been diagnosed with pEDS several months earlier after being referred for genetic testing by a dermatologist. It should be noted that in these siblings pEDS had been misinterpreted for years by health care specialists despite the patients' periodontal disease, which had appeared at the age of 3 years. The subsequent effects of periodontal disease in these patients jeopardized the survival prognosis of their teeth. It may be stated that, in spite of pEDS's status as a rare syndrome, the dental practitioner can play a key role in the early diagnosis by responding appropriately to periodontal manifestations at early stages. (Quintessence Int 2021;52:166-174; doi: 10.3290/j.qi.a45263)

Improvement of aesthetics in a patient with tetracycline stains using the injectable composite resin technique: case report with 24-month follow-up.

This case report describes the conservative management of generalised tetracycline stains by means of the injectable composite resin technique. This time-efficient technique obtained optimal and satisfactory aesthetic outcomes. Both the patient and the clinician were very satisfied with the results. Composite veneers realised with injected flowable resin composites are an effective treatment, with minimally invasive possibilities, providing the case selection protocol is correct. In addition, it can be considered as a more economical treatment option.

Precision and practical usefulness of intraoral scanners in implant dentistry: A systematic literature review.

BACKGROUND: This systematic review aimed to evaluate the efficiency and accuracy of digital impression techniques for implant-supported restorations, and to assess their economic feasibility. MATERIAL AND METHODS: Two independent electronic database searches were conducted in the Pubmed/MedLine, Cochrane Library, and Lilacs databases complimented by a manual search, selecting relevant clinical and in vitro studies published between 1st January 2009 and 28st February 2019. All type of studies (in vivo and in vitro) were included in this systematic review. RESULTS: Twenty-seven studies (8 in vivo and 19 in vitro studies) fulfilled the inclusion criteria. No meta-analysis was performed due to a large heterogeneity of the study protocols. The passive fit of superstructures on dental implants presented similar results between digital and conventional impression techniques. The studies considered that several factors influence the accuracy of implant impression taking: distance and angulation between implants, depth of placement, type of scanner, scanning strategy, characteristics of scanbody, and operator experience. Regarding the economic viability of intraoral scanning systems, only one study reported any benefit in comparison with conventional techniques. CONCLUSIONS: Digital impressions of dental implants can be considered a viable alternative in cases of one or two contiguous dental implants. However, more studies are needed to evaluate the accuracy of digital techniques in full-arch implant-supported restorations. Key words:Intraoral scanner, dental implant, prosthesis, misfit, systematic review.

Epidemiological Features and Clinical Repercussions of Supernumerary Teeth in a Multicenter Study: A Review of 518 Patients with Hyperdontia in Spanish Population.

OBJECTIVES: The aim of this study was to establish the prevalence of supernumerary teeth (ST) in a sector of the population of Madrid, as well as possible complications associated with the presence of these teeth. MATERIALS AND METHODS: The study investigated patients (n = 28,114) who sought dental care at the Oral Surgery Service of three different centers between May 2005 and April 2018. Cases that did not present this numeric dental developmental variation were discarded, registering only those presenting ST. STATISTICAL ANALYSIS: Statistical analysis consisted of univariate analysis (mean, standard deviation, median, etc.), bivariate analysis applying the chi-squared test, whereby statistical significance was established with a confidence interval (CI) of 95% (p < 0.05), and multivariate analysis by means of classification and decision trees. RESULTS: The study found ST in 518 patients, representing a prevalence of 1.84%. The 518 patients presented a total of 726 ST. Distomolars were the most common, representing 37.7% of the sample, followed by premolars (20.1%). About 70.5% of the sample were located in the maxilla and 78% of ST were impacted. Radiographs revealed that 39.7% of STs were associated with disorders. Supplementary morphology appeared in 52.1% of the sample. CONCLUSIONS: Although mesiodens is considered the most common ST, the present study found distomolars and supernumerary premolars to be the most frequently occurring. Pathology was associated with 39.7% of the ST sample. Early diagnosis allows optimal patient management and treatment planning, with intervention at an appropriate time to prevent complications in development and so reduce later treatment need.

Clinical repercussions and epidemiological considerations of supernumerary canines: A 26 case series

Background: To establish the prevalence of supernumerary canines (SNC) in a sector of the population of Madrid (Spain), as well possible complications associated with this unusual developmental variation. Study design: This observational study was performed between 2005 and 2017, among 21,615 patients seeking dental treatment at the Faculty of Dentistry, Complutense University of Madrid (Spain), and at the Virgen de la Paloma Hospital, Madrid (Spain); 22 patients with 26 SNCs were diagnosed. These 22 patients underwent clinical and radiological exploration, registering patient data. Results: SNCs presented a prevalence of 0.10% of the study population. The supernumerary teeth (SNT) were located in the upper maxilla more frequently (61.54%) than the mandible (38.46%). 69.23% were found to be impacted, also causing the impaction of the permanent canine in 53.85% of these cases. In 15.38%, follicular expansion > 3mm was observed. SNCs were associated with other SNT in only four patients. Conclusions: Despite of the fact that the SNCs are usually diagnosed casually in the course of radiological explora-tion, in the present study over half of them (53.85%) caused impaction of the permanent canine. Early diagnosis allows optimal patient management and treatment planning, with intervention at an appropriate time to prevent complications in development and so reduce later treatment need

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Fracture load of metal-ceramic, monolithic, and bi-layered zirconia-based posterior fixed dental prostheses after thermo-mechanical cycling.

OBJECTIVES: This study aims to evaluate the fracture load of differently fabricated 3-unit posterior fixed dental prostheses (FDPs) with an intermediate pontic. METHODS: Fifty sets of two stainless-steel abutments were randomly assigned to five groups (n = 10 each) depending on the material and technique used for manufacturing the FDPs: (1) Metal-ceramic (MC, control); (2) Lava Zirconia (LZ, bi-layered); (3) Lava Plus (LM, monolithic); (4) VITA In-Ceram YZ (YZ, bi-layered); and (5) IPS e-max ZirCAD (ZZ, bi-layered). After being luted to the dies, all FDPs were submitted to thermo-mechanical cycling (120,000 masticatory cycles, 50 N; plus 774 thermal cycles of 5 °C/55 °C, dwell time: 30 s). Samples were then subjected to a three-point bending test until fracture in a universal testing machine (cross-head speed: 1 mm/min). Fracture load of the veneering ceramic (VF) and total fracture load (TF) were recorded. Microstructure and failure patterns were assessed. Data was analysed using one-way ANOVA and Tukey HSD post-hoc tests (α = 0.05). RESULTS: MC restorations recorded higher VF and TF values than did zirconia FDPs (p = 0.0001), which showed no between-group differences. Within the bi-layered groups, TF was significantly higher than VF. LM pieces registered lower average grain size than did LZ specimens (p = 0.001). Overall, the connector was the weakest part. CONCLUSIONS: All of the groups tested could withstand clinical chewing forces in terms of average fracture load. Zirconia-based samples performed similarly to each other, but showed lower mean fracture load values than did metal-ceramic ones. CLINICAL SIGNIFICANCE: Monolithic zirconia may be recommendable for solving the chipping problem.

All-ceramic inlay-retained fixed dental prostheses for replacing posterior missing teeth: A systematic review.

PURPOSE: To evaluate the current status of all-ceramic inlay-retained fixed dental prostheses (CIR-FDPs) for the replacement of posterior teeth. STUDY SELECTION: Screening of titles and abstracts, full-text analysis for inclusion eligibility, quality assessment, data extraction and evaluation of the scientific evidence were performed independently by two reviewers. The electronic databases MEDLINE/PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and Compludoc were searched with no restriction to publication date or language. The quality of the studies was evaluated through: the original 'QDP' ('Questionnaire for selecting articles on Dental Prostheses') (for research papers); the 'Guidelines for managing overviews' of the Evidence-Based Medicine Working Group (for reviews); the Cochrane risk of bias tool; and the GRADE scale for grading scientific evidence. RESULTS: This review started with 4942 articles, which were narrowed down to 23 according to the selection criteria. The data was not statistically treated because of the heterogeneity of the studies. Zirconia-based CIR-FDPs may be recommended for restoring posterior single missing teeth, although the prosthesis/tooth bonded interface has yet to be improved. The addition of lateral wings to the classical inlay preparation seems promising. The weakest parts of CIR-FDPs are the connectors and retainers, while caries and endodontic problems are the most common biological complications. The fabrication of CIR-FDPs with monolithic zirconia may eliminate chipping problems. CONCLUSIONS: A three-unit CIR-FDP is a viable treatment option for replacing a posterior missing tooth. Appropriate case selection, abutment preparation and luting procedures may be decisive for clinical success.

Validation of the "Quality of Life related to function, aesthetics, socialization, and thoughts about health-behavioural habits (QoLFAST-10)" scale for wearers of implant-supported fixed partial dentures.

OBJECTIVES: To validate the 'Quality of Life related to function, aesthetics, socialization, and thoughts about health-behavioural habits (QoLFAST-10)' questionnaire for assessing the whole concept of oral health-related quality of life (OHRQoL) of implant-supported fixed partial denture (FPD) wearers. METHODS: 107 patients were assigned to: Group 1 (HP; n=37): fixed-detachable hybrid prostheses (control); Group 2 (C-PD, n=35): cemented partial dentures; and Group 3 (S-PD, n=35): screwed partial dentures. Patients answered the QoLFAST-10 and the Oral Health Impact Profile (OHIP-14sp) scales. Information on global oral satisfaction, socio-demographic, prosthetic, and clinical data was gathered. The psychometric capacity of the QoLFAST-10 was investigated. The correlations between both indices were explored by the Spearman's rank test. The effect of the study variables on the OHRQoL was evaluated by descriptive and non-parametric probes (α=0.05). RESULTS: The QoLFAST-10 was reliable and valid for implant-supported FPD wearers, who attained comparable results regardless of the connection system being cement or screws. Both fixed partial groups demonstrated significantly better social, functional, and total satisfaction than did HP wearers with this index. All groups revealed similar aesthetic-related well-being and consciousness about the importance of health-behavioural habits. Several study variables modulated the QoLFAST-10 scores. CONCLUSIONS: Hybrid prostheses represent the least predictable treatment option, while cemented and screwed FPDs supplied equal OHRQoL as estimated by the QoLFAST-10 scale. CLINICAL SIGNIFICANCE: The selection of cemented or screwed FPDs should mainly rely on clinical factors, since no differences in patient satisfaction may be expected between both types of implant rehabilitations.

Validation of a new, specific, complete, and short OHRQoL scale (QoLFAST-10) for wearers of implant overdentures and fixed-detachable hybrid prostheses.

OBJECTIVES: To validate a new index for assessing the whole concept of oral health-related quality of life (OHRQoL) of implant-prosthesis wearers. METHODS: 113 patients who were not requesting dental treatment were assigned to: Group 1 (CD; n=38): complete denture users (control); Group 2 (IO; n=38): implant overdenture wearers; and Group 3 (HP; n=37): hybrid implant prosthesis users. Patients answered the newly-designed 'Quality of Life related to Function, Aesthetics, Socialization, and Thoughts about health-behavioural habits' (QoLFAST-10) and the Oral Health Impact Profile (OHIP-20sp) questionnaires. Information on global oral satisfaction, socio-demographic, clinical, and prosthetic-related data were gathered. The QoLFAST-10 was investigated for reliability and validity. The Spearman's test determined the correlations between both indices' scores. Descriptive and non-parametric probes were run to assess the influence of the study variables on the OHRQoL (α=0.05). RESULTS: The QoLFAST-10 confirmed its psychometric capacity. HP wearers reported significantly better global and functional satisfaction than did IO wearers. The latter revealed significantly less consciousness about the importance of health-behavioural habits than did CD and HP groups. The level of education, complaints about the mouth, and the global oral satisfaction measures significantly modulated the QoLFAST-10 scores. CONCLUSIONS: Implant overdentures supplied lower functional and global satisfaction than did hybrid prostheses, and represent the least predictable option concerning the maintenance of the restoration. CLINICAL SIGNIFICANCE: The QoLFAST-10 may help in estimating the impact of implant restorations on patients' well-being. In this regard, hybrid prostheses seem to be the implant treatment of choice when compared with overdentures.

Fracture Load Before and After Veneering Zirconia Posterior Fixed Dental Prostheses.

PURPOSE: To evaluate the fracture load of 3-unit zirconia-based posterior fixed dental prostheses (FDPs) before and after veneering the frameworks. MATERIALS AND METHODS: Forty standardized stainless-steel master dies were fabricated (height: 5 mm, convergence: 6º, chamfer: 1 mm) and randomly screwed in pairs onto metal bases. The bases were randomly divided into two groups (n = 20 each) according to the zirconia CAD/CAM system used for constructing 3-unit structures for FDPs: group 1 (L): Lava All-ceramic, group 2 (Z): IPS e.max ZirCAD. Half of the zirconia structures per group were randomly selected and veneered, while the remaining half was left unveneered. The specimens were luted in standard fashion onto the stainless steel master dies using conventional glass ionomer cement. All specimens were tested for fracture load (FL). Specimens were subjected to a three-point bending test until fracture by applying an axial compressive load at the central fossa of the pontics with a universal testing machine at a 0.5 mm/min crosshead speed. Wilcoxon's rank-sum test and Weibull statistics were used for statistical analysis (α = 0.05). RESULTS: L structures recorded significantly higher values of load to fracture than the Z group both before and after veneering. Within each ceramic group, no differences were found between unveneered and veneered frameworks. CONCLUSIONS: Although further studies are necessary to corroborate these findings, both zirconia systems could be recommended for restoring posterior teeth on the basis of the fracture load values recorded in this experiment (>1000 N). The veneering procedure did not affect the overall load to fracture in any group.

Actualización sobre la optimización de la estética en prótesis fija mediante el manejo tisula / Update on the optimisation of aesthetics in fixed protheses through tissue handling

Las restauraciones localizadas en la zona estética orofacial son un reto especialmente difícil cuando existe pérdida acusada del reborde residual. En este trabajo se revisan distintas opciones de tratamiento para mejorar la apariencia de los tejidos blandos en los tratamientos con prótesis fija convencional. Para ello se han seleccionado artículos científicos nacionales e internacionales publicados en los últimos diez años. Para la introducción de conceptos no se establece límite de antigüedad. Básicamente, los hallazgos obtenidos de la revisión bibliográfica pueden sintetizarse en lo siguiente: una vez realizada una correcta selección del caso, distintos tipos de tratamiento demostraron aportar resultados satisfactorios para la estética de los tejidos blandos en el tratamiento con prótesis fija convencional. En primer lugar, se proponen tratamientos destinados a modificar la esté- tica manteniendo los tejidos duros y blandos (pónticos ovoides, tratamientos ortodóncicos, técnicas de preservación alveolar, regeneración tisular guiada, injerto monocortical). En segundo lugar, se indican tratamientos quirúrgicos de tejidos duros (osteoplastia/ostectomía) y blandos (injertos de tejido blando, gingivoplastia/gingivectomía, distintos tipos de colgajo). Como última indicación, los materiales de restauración actuales permiten alcanzar resultados estéticos aceptables. En la actualidad, tanto los tratamientos quirúrgicos como los protésicos son considerados estrategias valiosas para realizar un adecuado manejo tisular. El injerto de tejido conectivo es el procedimiento quirúrgico más predecible en el tratamiento de las recesiones, mientras que los pónticos constituyen el procedimiento protésico de elección para obtener una estética apropiada del margen gingival (AU)

Restorations in the aesthetic orofacial zone are particularly challenging in presence of intense resorption of the residual ridge. In this paper various treatment options are reviewed focusing on the improvement of the appearance of the soft tissues combined with conventional fixed prostheses. A deep and rigorous selection of national and international scientific papers published in the last ten years has been made. No age limit was set to describe the key concepts. Basically, the findings that emerge from the literature review can be summarized as follows: once made a correct selection of the case, different types of treatments have been shown to provide satisfactory aesthetic of the soft tissues in combination with conventional fixed prostheses. Treatments that intend to modify the aesthetics preserving hard and soft tissues are proposed (i.e., ovoid pontics, orthodontic treatment, alveolar preservation techniques, guided tissue regeneration, monocortical graft). In addition, surgical treatments including hard tissue (osteoplasty / ostectomy) and soft tissue modification (i.e., soft tissue grafts, gingivoplasty / gingivectomy, various types of flap, etc.) are detailed. Nowadays, both prosthetic and surgical treatments are considered valuable strategies for adequate tissue handling. The connective tissue graft may be considered as the most predictable surgical procedure in the management of recessions, whereas pontics are the first choice for achieving suitable aesthetic results in shaping the gingival margin (AU)

Effect of electric arc, gas oxygen torch and induction melting techniques on the marginal accuracy of cast base-metal and noble metal-ceramic crowns.

OBJECTIVES: The aim of this study was to identify the most appropriate alloy composition and melting technique by evaluating the marginal accuracy of cast metal-ceramic crowns. METHODS: Seventy standardised stainless-steel abutments were prepared to receive metal-ceramic crowns and were randomly divided into four alloy groups: Group 1: palladium-gold (Pd-Au), Group 2: nickel-chromium-titanium (Ni-Cr-Ti), Group 3: nickel-chromium (Ni-Cr) and Group 4: titanium (Ti). Groups 1, 2 and 3 were in turn subdivided to be melted and cast using: (a) gas oxygen torch and centrifugal casting machine (TC) or (b) induction and centrifugal casting machine (IC). Group 4 was melted and cast using electric arc and vacuum/pressure machine (EV). All of the metal-ceramic crowns were luted with glass-ionomer cement. The marginal fit was measured under an optical microscope before and after cementation using image analysis software. All data was subjected to two-way analysis of variance (ANOVA). Duncan's multiple range test was run for post-hoc comparisons. The Student's t-test was used to investigate the influence of cementation (α=0.05). RESULTS: Uncemented Pd-Au/TC samples achieved the best marginal adaptation, while the worst fit corresponded to the luted Ti/EV crowns. Pd-Au/TC, Ni-Cr and Ti restorations demonstrated significantly increased misfit after cementation. CONCLUSIONS: The Ni-Cr-Ti alloy was the most predictable in terms of differences in misfit when either torch or induction was applied before or after cementation. Cemented titanium crowns exceeded the clinically acceptable limit of 120µm. CLINICAL SIGNIFICANCE: The combination of alloy composition, melting technique, casting method and luting process influences the vertical seal of cast metal-ceramic crowns. An accurate use of the gas oxygen torch may overcome the results attained with the induction system concerning the marginal adaptation of fixed dental prostheses.

Oral health-related quality of life in complete denture wearers depending on theirsocio-demographic background, prosthetic-related factors and clinical condition

Objectives: To investigate the differences in impact on oral health-related quality of life (OHRQoL) among complete denture wearers depending on their socio-demographic characteristics, prosthetic-related factors and oral status. Study Design: 51 patients aged 50-90 years treated, from 2005 to 2010, with at least one complete denture at the Department of Buccofacial Prostheses of the Complutense University (Madrid) were enrolled in this crosssectional study. All of the participants answered the Oral Health Impact Profile (OHIP-14sp) questionnaire. The additive scoring method was used. The prevalence of impacts was calculated by using the occasional threshold (..) (AU)

Oral health-related quality of life in complete denture wearers depending on their socio-demographic background, prosthetic-related factors and clinical condition.

OBJECTIVES: To investigate the differences in impact on oral health-related quality of life (OHRQoL) among complete denture wearers depending on their socio-demographic characteristics, prosthetic-related factors and oral status. STUDY DESIGN: 51 patients aged 50-90 years treated, from 2005 to 2010, with at least one complete denture at the Department of Buccofacial Prostheses of the Complutense University (Madrid) were enrolled in this cross-sectional study. All of the participants answered the Oral Health Impact Profile (OHIP-14sp) questionnaire. The additive scoring method was used. The prevalence of impacts was calculated by using the occasional threshold (OHIP-14sp score ≥ 2). Socio-demographic and prosthetic-related variables were gathered. Patients underwent clinical examination to assess their oral condition. Descriptive probes and Chi-Square tests were run (p ≤ 0.05). RESULTS: The predominant participants' profile was that of a man with a mean age of 69 years wearing complete dentures in both the maxilla and the mandible. The prevalence of impact was 23.5%, showing an average score of 19 ± 9.8. The most affected domains were "functional limitation" and "physical pain", followed by "physical disability". Minor impacts were recorded for the psychological and social subscales ("psychological discomfort", "psychological disability", "social disability" and "handicap"). The prosthesis' location significantly influenced the overall patient satisfaction, the lower dentures being the less comfortable. Having a complete removable denture as antagonist significantly hampered the patient satisfaction. Patients without prosthetic stomatitis and those who need repairing or changing their prostheses, recorded significantly higher OHIP-14sp total scores. CONCLUSIONS: The use of conventional complete dentures brings negative impacts in the OHRQoL of elderly patients, mainly in case of lower prostheses that required reparation or substitution, with a removable total denture as antagonist. The prosthetic stomatitis in this study was always associated to other severe illness, which may have influenced the self-perceived discomfort with the prostheses, as those patients were daily medicated with painkillers.

Misfit and microleakage of implant-supported crown copings obtained by laser sintering and casting techniques, luted with glass-ionomer, resin cements and acrylic/urethane-based agents.

OBJECTIVES: This study evaluated the marginal misfit and microleakage of cement-retained implant-supported crown copings. METHODS: Single crown structures were constructed with: (1) laser-sintered Co-Cr (LS); (2) vacuum-cast Co-Cr (CC) and (3) vacuum-cast Ni-Cr-Ti (CN). Samples of each alloy group were randomly luted in standard fashion onto machined titanium abutments using: (1) GC Fuji PLUS (FP); (2) Clearfil Esthetic Cement (CEC); (3) RelyX Unicem 2 Automix (RXU) and (4) DentoTemp (DT) (n=15 each). After 60 days of water ageing, vertical discrepancy was SEM-measured and cement microleakage was scored using a digital microscope. Misfit data were subjected to two-way ANOVA and Student-Newman-Keuls multiple comparisons tests. Kruskal-Wallis and Dunn's tests were run for microleakage analysis (α=0.05). RESULTS: Regardless of the cement type, LS samples exhibited the best fit, whilst CC and CN performed equally well. Despite the framework alloy and manufacturing technique, FP and DT provide comparably better fit and greater microleakage scores than did CEC and RXU, which showed no differences. CONCLUSIONS: DMLS of Co-Cr may be a reliable alternative to the casting of base metal alloys to obtain well-fitted implant-supported crowns, although all the groups tested were within the clinically acceptable range of vertical discrepancy. No strong correlations were found between misfit and microleakage. Notwithstanding the framework alloy, definitive resin-modified glass-ionomer (FP) and temporary acrylic/urethane-based (DT) cements demonstrated comparably better marginal fit and greater microleakage scores than did 10-methacryloxydecyl-dihydrogen phosphate-based (CEC) and self-adhesive (RXU) dual-cure resin agents.

Clinical evaluation of the incidence of prosthetic complications in implant crowns constructed with UCLA castable abutments. A cohort follow-up study.

OBJECTIVES: To evaluate the incidence of prosthetic complications in implant-retained crowns made with UCLA castable abutments and to identify possible risk factors with a view to establishing recommendations to help predict the success of such restorations. METHODS: A cohort follow-up study was carried out in 71 partially dentate patients rehabilitated with 93 implant-retained single crowns. Data regarding socio-demographic background, anatomical features, implant-, and prosthesis-related variables were recorded. The incidence rate (%), relative risk (RR) and odds ratio (OR) were applied for predictive risk factors. ANOVA and Student t-tests were used to compare quantitative variables, the chi-square test was used to compare proportions and also a logistic regression analysis was performed. The statistical significance was set at α = 0.05. RESULTS: Two implants (2.2%) were lost during the first year of function. The incidence of prosthetic complications in the observed mean period (26.2 ± 15.4 months) was 11.9%, consisting of screw loosening (10.8%) and ceramic fracture (1.1%). A higher tendency for prosthetic complications was noticed in posterior mandibular crowns restoring saddles longer than 10 mm with mesiodistal cantilevers longer than 6mm, having natural antagonists, after long-term use (>20 months), with initial torque values superior than 30 Ncm. CONCLUSIONS: Screw loosening is the most frequent complication in implant-retained crowns fabricated with UCLA abutments cast in cobalt-chromium. Nevertheless, the connection usually remains stable after retightening the screws. A high survival rate was recorded, and these prostheses may be a suitable treatment option. CLINICAL SIGNIFICANCE: Based on the study findings, the risk of prosthetic complications is expected to increase when long-span posterior edentulous areas are rehabilitated with single implant-supported crowns. The antagonist occlusal plane should be restored to prevent torsional forces and overloading. Implant systems with initial torque values less than 30 Ncm should be selected.

Differences in impact of patient and prosthetic characteristics on oral health-related quality of life among implant-retained overdenture wearers.

OBJECTIVES: To evaluate the oral health-related quality of life (OHRQoL) of implant-retained overdenture users. METHODS: 63 patients aged 50-90 years treated with at least one implant overdenture at the Complutense University (Madrid) in 2000-2010 were included. Of those, 42 answered the Oral Health Impact Profile (OHIP-14 sp) questionnaire. The additive method was used in the OHIP analysis. Data regarding sociodemographic background, overdenture features, and clinical factors were recorded. Sociodemographic and overdenture-related variables for the lost patients (n=21) were also gathered from their history files. Descriptive probes, Mann-Whitney and Kruskal-Wallis tests, and the Spearman correlation coefficient were applied (p ≤ 0.05). RESULTS: The predominant participants' profile was that of a 71-80-year-old woman wearing a mandibular overdenture with a bar retention system and a complete denture in the opposite jaw. 71.4% of the respondents suffered from some kind of impact on OHRQoL, showing an average score of 2.7 ± 3.0 (range: 0-13). 100% of respondents reported no impact for the "social disability" and "handicap" dimensions. The most prevalently affected domain was "physical pain", followed by "functional limitation" and "psychological discomfort". Variables such as the overdenture location or the retention system affected specific OHIP subscales (p ≤ 0.05). The greatest total score was achieved when the antagonist was a complete denture (p<0.01). CONCLUSIONS: Implant-retained overdentures provide a seemingly acceptable quality of life in the elderly population studied, irrespective of the influence of the location, retention system, and antagonist. CLINICAL SIGNIFICANCE: Although further research is necessary, mandibular implant overdentures are more comfortable than maxillary ones. Ball-retained prostheses facilitate eating the most, whereas the presence of oral ulcers and/or candidiasis was only detected in the case of bars, thus impairing OHRQoL. A complete denture as antagonist decreases the patient overall satisfaction.