Effect of crown height on the screw joint stability of zirconia screw-retained crowns.

STATEMENT OF PROBLEM: Medium- to long-term data for the performance of zirconia crowns with titanium (Ti) bases are sparse, particularly when the crown height space and occlusal loads are high. PURPOSE: The purpose of this in vitro study was to assess the effect of the height of zirconia screw-retained implant crowns with a Ti base on the screw joint stability after cyclic loading. A secondary aim was to investigate the survival of zirconia crowns of different heights after cyclic loading. MATERIAL AND METHODS: Twenty-one internal connection implants were secured between fiberglass-reinforced epoxy resin sleeves. Mandibular first molar monolithic zirconia crowns with 3 different heights (6 mm, 10 mm, and 14 mm) were milled and bonded to the Ti bases (n=7). The screws were tightened to 30 Ncm, and a 30-degree 120-N cyclic load was applied to the crowns at 2 Hz for 5 million cycles. After 5 million cycles, the crowns were evaluated for stability, and the same protocol was repeated for 275-N and 435-N loads for 5 million cycles each. After loading, the detorque values were recorded. Failure was characterized based on whether the crown, screw, and/or implant fracture was observed. The detorque values were analyzed by using a 1-way-ANOVA with the restricted maximum likelihood estimation. The percentage of torque loss was calculated. The LIFETEST procedure was used to analyze the survival probability of the groups (α=.05). RESULTS: The effect of crown height on the detorque values of screws was not found to be statistically significant (P>.05). The mean detorque value for 6-mm crowns was 23.5 Ncm, 24.4 Ncm for 10-mm crowns, and 22.1 Ncm for 14-mm crowns. A significant effect of crown height was found on the survival (P=.006), and the time-to-failure survival of 14-mm crowns was significantly lower than the survival of 6 mm and 10 mm crowns (P=.020), where no failures were observed. Four 14-mm crowns failed between the 1 and 2 million cycles after the loads were increased to 435 N. The failure modes were the same for all the crowns, implants, and screws fractured. CONCLUSIONS: When the tested internal connection implant was used, the crown height did not affect the detorque values, and 14-mm crowns performed similarly to the shorter crowns in terms of torque loss after cyclic loading. However, survival of the 14-mm crown-implant complex was lower, resulting in screw and implant fractures.

Weighted mandibular complete denture fabricated by using selective laser melting: A clinical report.

The rehabilitation of patients with severely resorbed mandibular ridges can be a clinical challenge when rehabilitation with endosteal implants is not the elected treatment. Historically, weighted mandibular complete dentures have been used successfully to manage patients with severely resorbed ridges, and the weight of their cast metal has been calculated by using the weight of the wax and the density of the alloy. This clinical report presents the management of an 87-year-old woman with a severely resorbed mandibular ridge by using a weighted mandibular complete denture fabricated by using selective laser melting (SLM) technology in which the weight of the metal base was calculated by using the volume of the digital file used for manufacture.

Effect of Crown Height on the Screw Stability of Titanium Screw-Retained Crowns.

PURPOSE: The aim of this in vitro study was to evaluate the effect of crown height on the screw stability of screw-retained titanium implant crowns subjected to cyclic loading conditions. MATERIALS AND METHODS: Twenty-one implants with internal hex connections were placed in epoxy resin holders. Mandibular first molar screw-retained titanium implant crowns with UCLA type, crown-abutment connections were CAD/CAM fabricated. Seven crowns of 3 different heights (6 mm, 10 mm, and 14 mm) were made. The crowns were seated onto the implants and screws were tightened to 30 Ncm. The implants were clamped into holders and stepwise cyclic loads were applied to the occlusal surface at 30-degree angles to the long axes of the crowns. The detorque values were measured after each 5 million cycles. Before increasing the applied load, the crowns were secured with new screws and tightened to 30 Ncm. Failure times, survival estimates and detorque values were then analyzed. (alpha = 0.05). RESULTS: Crown height did not significantly affect detorque values. However, five 14-mm crowns failed with varying fractures during the 475 N loading condition. Overall, a significantly lower survival for 14 mm crowns was found compared to 6 mm and 10 mm crowns (p = 0.004). CONCLUSIONS: Crown heights of one-piece screw-retained titanium implant crowns did not significantly affect detorque values. Screw fracture, however, was greater for crown height of 14 mm than those of 6 mm and 10 mm.

A comparison of implant complications and failures between the maxilla and the mandible.

STATEMENT OF PROBLEM: Identifying factors that affect the clinical outcomes of implant therapy is important. PURPOSE: The purpose of this retrospective study was to determine whether implant location was a factor affecting the complication and failure rates of single-tooth implant-supported restorations in a predoctoral setting. MATERIAL AND METHODS: The charts of 431 patients treated with a surgically placed dental implant and restored with a single crown in the predoctoral clinic were analyzed. Data on implant location, type of complication (surgical or prosthetic), and type of failure were collected and analyzed according to implant location using the Fisher Exact Test and Mantel-Haenszel Exact Chi Square Test analysis (α=.05). RESULTS: The charts revealed 158 complications (68 surgical and 90 prosthetic) in 110 patients, and 3.9% of the implants failed. No statistically significant difference was found between the number of surgical complications or prosthetic complications in the maxilla and the mandible (P=.469). CONCLUSIONS: Jaw location (maxilla compared with mandible) of the implant had no statistically significant impact on the incidence of surgically or prosthetically related complications. No statistically significant difference was found in overall implant failures, surgical failures, and prosthetic failures between maxillary and mandibular implants.

A critical appraisal of the systematic review process: systematic reviews of zirconia single crowns.

STATEMENT OF PROBLEM: Systematic reviews analyze the data of published research in an effort to assemble the scientific evidence to help clinicians apply evidence-based information in decision making. The quality of systematic reviews varies greatly. PURPOSE: The purpose of this study was to critically appraise the current systematic review process by evaluating systematic reviews that pertain to zirconia-based single crowns. MATERIALS AND METHODS: The following PICO (patients, intervention, comparison, outcome) question was formulated: "In adults, how does the long-term prognosis of zirconia-based single crowns compare with conventional single crowns on natural teeth?" An electronic search was performed in PubMed and the Cochran Library for articles published in English between 1950 and October 2012. Additional manual searches were completed. To be included in the analysis, the study must have been a systematic review, published in an English-speaking peer-reviewed journal, and evaluated zirconia crowns on teeth. Two examiners qualitatively evaluated the publications with an Assessment of Multiple Systematic Reviews checklist and the Oxford Systematic Review Appraisal form. RESULTS: Three systematic reviews were identified that met the search criteria. Two studies met 5 of the 11 Assessment of Multiple Systematic Reviews criteria, whereas the third met only 1 criterion. The same 2 studies met 3 of the 5 Oxford Systematic Review Appraisal criteria and the third met only 2 criteria. CONCLUSION: Because of the variation in methodologies, systematic reviews should be interpreted cautiously. The Assessment of Multiple Systematic Reviews Checklist and the Oxford Systematic Review Appraisal Sheet are practical tools for appraising and determining the quality of systematic reviews.

A critical appraisal of evidence-based dentistry: the best available evidence.

STATEMENT OF PROBLEM: The principle of evidence-based dentistry requires that relevant scientific literature be integrated into the dentist's practice and the patient's treatment needs and wishes. This approach involves critically appraising the scientific literature for the best available evidence in order to make clinical decisions. PURPOSE: The purpose of the study was to critically appraise the process by which a practitioner attempts to make an evidenced-based clinical decision. This process is illustrated by evaluating the clinical literature pertaining to zirconia-based single crowns. MATERIAL AND METHODS: An electronic search was performed in PubMed and the Cochrane Library by using Boolean operators for articles published in English between January 1950 and October 2012 to address the PICO (patients, intervention, comparison, outcome) question, "In adults, how does the long term prognosis of zirconia-based single crowns compare to conventional single crowns on natural teeth?" Comparisons were made across the publications to determine the quality of relevant information. RESULTS: Three systematic reviews included 4 clinical trials. Two randomized clinical trials and 1 retrospective study met the search criteria but were not identified in the systematic reviews. The definitions of the outcomes and the presentation of the data varied among studies. CONCLUSIONS: The lack of standardization of reporting data, the nonstandardized definitions of outcomes, and the impact of the length of the research study were identified as problems that need to be addressed to improve the quality of systematic reviews and other clinical trials.

Assessment of occlusion curriculum in predoctoral dental education: report from ACP Task Force on Occlusion Education.

PURPOSE: The purposes of this report were to (1) assess the current occlusion curriculum in the predoctoral prosthodontic education of US dental institutions and (2) to examine the opinions of faculty, course directors, and program directors on the contents of occlusion curriculum. MATERIALS AND METHODS: The Task Force on Occlusion Education from the American College of Prosthodontists (ACP) conducted two surveys using a web-based survey engine: one to assess the current status of occlusion education in predoctoral dental education and another to examine the opinions of faculty and course directors on the content of occlusion curriculum. The sections in the surveys included demographic information, general curriculum information, occlusion curriculum for dentate patients, occlusion curriculum for removable prosthodontics, occlusion curriculum for implant prosthodontics, temporomandibular disorder (TMD) curriculum, teaching philosophy, concepts taught, and methods of assessment. The results from the surveys were compiled and analyzed using descriptive statistics. The results from the two surveys on general concepts taught in occlusion curriculum were sorted and compared for discrepancies. RESULTS: According to the predoctoral occlusion curriculum surveys, canine guidance was preferred for dentate patients, fixed prosthodontics, and fixed implant prosthodontics. Bilateral balanced occlusion was preferred for removable prosthodontics and removable implant prosthodontics. There were minor differences between the two surveys regarding the occlusion concepts being taught and the opinions of faculty members teaching occlusion. CONCLUSION: Two surveys were conducted regarding the current concepts being taught in occlusion curriculum and the opinions of educators on what should be taught in occlusion curriculum. An updated and clearly defined curriculum guideline addressing occlusion in fixed prosthodontics, removable prosthodontics, implant prosthodontics, and TMD is needed.

The dynamic natures of implant loading.

STATEMENT OF PROBLEM: A fundamental problem in fully understanding the dynamic nature of implant loading is the confusion that exists regarding the torque load delivered to the implant complex, the initial force transformation/stress/strain developed within the system during the implant complex assembly, and how the clamping forces at the interfaces and the preload stress impact the implant prior to any external loading. PURPOSE: The purpose of this study was to create an accurately dimensioned finite element model with spiral threads and threaded bores included in the implant complex, positioned in a bone model, and to determine the magnitude and distribution of the force transformation/stress/strain patterns developed in the modeled implant system and bone and, thus, provide the foundational data for the study of the dynamic loading of dental implants prior to any external loading. MATERIAL AND METHODS: An implant (Brånemark Mark III), abutment (CeraOne), abutment screw (Unigrip), and the bone surrounding the implant were modeled using HyperMesh software. The threaded interfaces between screw/implant and implant/bone were designed as a spiral thread helix assigned with specific coefficient of friction values. Assembly simulation using ABAQUS and LS-DYNA was accomplished by applying a 32-Ncm horizontal torque load on the abutment screw (Step 1), then decreasing the torque load to 0 Ncm to simulate the wrench removal (Step 2). The postscript data were collected and reviewed by HyperMesh. A regression analysis was used to depict the relationships between the torque load and the mechanical parameters. RESULTS: During the 32-Ncm tightening sequence, the abutment screw elongated 13.3 mum. The tightening torque generated a 554-N clamping force at the abutment/implant interface and a 522-N preload. The von Mises stress values were 248 MPa in the abutment at the abutment-implant interface, 765 MPa at the top of the screw shaft, 694 MPa at the bottom of the screw shaft, 1365 MPa in the top screw thread, and 21 MPa in the bone at the top of the implant-bone interface. This study also identified various characteristic isosurface stress patterns. The maximum stress magnitude to complete the von Mises stress joint pattern in the present model was 107 MPa during screw tightening, and was reduced to 104 MPa with removal of the wrench. Various specific stress patterns were identified within all elements of the implant complex during the assembly simulation. CONCLUSIONS: During the torque moment application, the abutment screw was elongated, and every 1.0-mum elongation of the screw was equivalent to a 47.9-N increase of the preload in the implant complex. The ideal index to determine the preload amount was the contact force at the interface between the screw threads and the threaded screw bore. The isosurface mode identified various characteristic stress patterns developed within the implant complex at the various interfaces during the assembly simulation. These patterns are the (1) spiral and ying-yang pattern of the XY stress, (2) spring, cap, clamping, and preload pattern of the ZZ stress, and (3) bone holding and joint pattern of the von Mises stress.

Probabilistic analysis of preload in the abutment screw of a dental implant complex.

STATEMENT OF PROBLEM: Screw loosening is a problem for a percentage of implants. A probabilistic analysis to determine the cumulative probability distribution of the preload, the probability of obtaining an optimal preload, and the probabilistic sensitivities identifying important variables is lacking. PURPOSE: The purpose of this study was to examine the inherent variability of material properties, surface interactions, and applied torque in an implant system to determine the probability of obtaining desired preload values and to identify the significant variables that affect the preload. MATERIAL AND METHODS: Using software programs, an abutment screw was subjected to a tightening torque and the preload was determined from finite element (FE) analysis. The FE model was integrated with probabilistic analysis software. Two probabilistic analysis methods (advanced mean value and Monte Carlo sampling) were applied to determine the cumulative distribution function (CDF) of preload. The coefficient of friction, elastic moduli, Poisson's ratios, and applied torque were modeled as random variables and defined by probability distributions. Separate probability distributions were determined for the coefficient of friction in well-lubricated and dry environments. The probabilistic analyses were performed and the cumulative distribution of preload was determined for each environment. RESULTS: A distinct difference was seen between the preload probability distributions generated in a dry environment (normal distribution, mean (SD): 347 (61.9) N) compared to a well-lubricated environment (normal distribution, mean (SD): 616 (92.2) N). The probability of obtaining a preload value within the target range was approximately 54% for the well-lubricated environment and only 0.02% for the dry environment. The preload is predominately affected by the applied torque and coefficient of friction between the screw threads and implant bore at lower and middle values of the preload CDF, and by the applied torque and the elastic modulus of the abutment screw at high values of the preload CDF. CONCLUSIONS: Lubrication at the threaded surfaces between the abutment screw and implant bore affects the preload developed in the implant complex. For the well-lubricated surfaces, only approximately 50% of implants will have preload values within the generally accepted range. This probability can be improved by applying a higher torque than normally recommended or a more closely controlled torque than typically achieved. It is also suggested that materials with higher elastic moduli be used in the manufacture of the abutment screw to achieve a higher preload.

Design and Outcomes of a Comprehensive Care Experience Level System to Evaluate and Monitor Dental Students' Clinical Progress.

A Comprehensive Care Experience Level (CCEL) system that is aligned with Commission on Dental Accreditation (CODA) standards, promotes comprehensive care and prevention, and addresses flaws observed in previous Relative Value Units (RVU)-based programs has been implemented at the School of Dental Medicine, Case Western Reserve University since 2011. The purpose of this article is to report on the design, implementation, and preliminary outcomes of this novel clinical evaluation system. With the development of the CCEL concept, it was decided not to award points for procedures performed on competency exams. The reason behind this decision was that exams are not learning opportunities and are evaluated with summative tools. To determine reasonable alternative requirements, production data from previous classes were gathered and translated into CCEL points. These RVU points had been granted selectively only for restorative procedures completed after the initial preparation stage of the treatment plan, and achievement of the required levels was checked at multiple points during the clinical curriculum. Results of the CCEL system showed that low performing students increased their productivity, overall production at graduation increased significantly, and fluoride utilization to prevent caries rose by an order of magnitude over the RVU system. The CCEL program also allowed early identification and remediation of students having difficulty in the clinic. This successful implementation suggests that the CCEL concept has the potential for widespread adoption by dental schools. This method also can be used as a behavior modification tool to achieve specific patient care or clinical educational goals as illustrated by the way caries prevention was promoted through the program.

Comparison of Preprosthetic Implant Complications and Failures Between Obese and Nonobese Patients.

PURPOSE: Obesity as a systemic risk factor associated with implant failure or other complications has not been studied. The aim of this study was to compare the frequency of implant failure and complications between obese and nonobese patients. MATERIALS AND METHODS: Charts from 220 partially edentulous patients with 321 implants were examined for demographic information, medical health history, diabetes, smoking, patient-reported height and weight, periodontal status (no, mild, moderate, or severe periodontitis), tooth number, date of the implant and prosthesis placement, and treatment notes pertinent to the complications or failure. Subjects were classified according to their body mass index (BMI) as normal (18.5 to 24.5 kg/m(2)), overweight (25 to 29.9 kg/m(2)), or obese (≥ 30 kg/m(2)) based on self-reported height and weight. Variables including sex, smoking, diabetes, and periodontal condition were considered as confounders. Data were analyzed to examine differences in frequency of complications and occurrence of failures. RESULTS: Implant failure was low (2.1%) and did not differ by BMI category. Compared with normal BMI patients, obese patients had increased odds of experiencing an implant complication (OR = 4.9, 95% CI [1.4, 17.6]) after adjustment for other variables. Diabetes was not associated with an increased risk of complications; obese patients with diabetes had decreased odds of an implant complication compared with obese patients without diabetes. CONCLUSION: No association was observed between obesity and implant failures. BMI category was associated with implant complications; obese patients have greater odds of experiencing implant complications postsurgically. Treating obese patients with the existing protocol for diabetic patients (antibiotic regimens, more frequent follow-up, and maintenance appointments) may improve clinical outcomes.

Characteristics of the Cochrane Oral Health Group systematic reviews.

The Cochrane Oral Health Group (COHG) was formed in 1994 with the aim of producing systematic reviews that primarily include oral health randomized controlled trials (RCTs). The purpose of this cross-sectional study was to characterize reviews published by the COHG. In September 2013, the COHG database was accessed, and all publications were downloaded. Reviews with no studies identified according to the inclusion criteria were labeled "empty reviews." The complete Cochrane database included a total of 5,697 reviews, of which the COHG database included 142 reviews. Of these 142, 69 (48.6%) did not reach a conclusion, including 20 (14.1%) that were identified as empty reviews. Of the 122 non-empty reviews, 116 (95.1%) were based exclusively on RCTs. The median number of RCTs and patients included in the non-empty reviews were seven and 489, respectively. The median number of included RCTs and patients for reviews that reached conclusions were 12 and 934, respectively, and there were five RCTs and 211 patients for reviews without conclusions. Overall, the characteristics of the Cochrane oral health reviews (OH-CSRs) were similar to Cochrane reviews published in other disciplines (All-CSRs). The authors observed a significant difference in the median number of RCTs and patients included when reviews that reached conclusions were separated from those that did not. A greater proportion of empty reviews were present in OH-CSRs compared with All-CSRs. Turning the Cochrane reviews into a tool that is more relevant in clinical practice will require implementation of a methodology allowing inclusion of non-RCTs while controlling for possible bias.

Comparison of implant and provisional placement protocols in sinus-augmented bone: a preliminary report.

PURPOSE: To evaluate preliminary data on clinical outcomes associated with timing of placement of single implant-supported provisional crowns and implants in augmented bone. MATERIALS AND METHODS: Twenty patients underwent sinus elevation bone grafting followed by a 6-month healing period before implant placement and immediate placement of a provisional crown (group [G] 1); 20 patients received sinus elevation bone grafting at the time of implant placement and immediate placement of a provisional crown (G2); 20 patients required no bone augmentation before implant placement and immediate placement of a provisional crown (G3); and 20 patients received sinus elevation bone grafting followed by a 6-month healing period before implant placement followed by a 6-month healing period before restoration (G4). The height of the crestal bone was measured and recorded to determine mean bone changes, and success rates were determined. RESULTS: Mean bone level comparisons were made between G2 and G3, G2 and G4, and G3 and G4. No statistically significant differences were found between the groups (P < .05). G1 was discontinued based on the initial results: two implants did not meet the 35-Ncm insertion test, and one implant failed within 1 month after implant placement. The 1-year implant survival rates were 86% (n = 12/14), 95% (n = 19/20), and 100% (n = 16/16) for G2, G3, and G4, respectively. Differences in survival rates between the groups were not statistically significant (P < .05). CONCLUSION: Implant survival is affected by the timing of sinus augmentation and implant placement in relation to the timing of crown placement. Implants that were restored immediately regardless of the timing of bone augmentation showed greater failure rates than implants in augmented bone with delayed restoration protocols or those that were restored immediately in sites without bone augmentation. Neither the timing of loading nor timing of implant placement in relation to bone augmentation surgery affected mean bone loss.

Evaluation of the precision of fit between the Procera custom abutment and various implant systems.

PURPOSE: It has been suggested that the CAD/CAM Procera custom abutment may be universally applied with multiple implant systems. An acceptable fit between the internal hexagon of an abutment and the external hexagon of various implant systems, along with true interchangeability of the Procera abutment screw, would support this concept. This study determined the precision of fit of the CAD/CAM-produced Procera abutment onto the external hexagon and bearing surfaces of implants from 6 implant manufacturers and the interchangeability of the Procera abutment screw with these systems. MATERIALS AND METHODS: This investigation consisted of 3 parts: (1) direct measurement of the internal hexagon and bearing surface of each Procera abutment and the external hexagon and the bearing surface of 6 implants from 6 different systems, (2) radiographic examination of 30 Procera abutment-implant junctions following tightening to 32 Ncm to determine the precision of fit between the bearing surfaces and the top of the external hexagon of the implant with the superior surface of the internal hexagon of the abutment, and (3) examination of 3 abutment screws and 3 implants from the various manufacturers for interchangeability based on American National Standards. RESULTS: The mean flat-to-flat external hexagons of the implants measured between 2.67 and 2.69 mm. The Procera abutment's flat-to-flat internal hexagon measured 2.73 mm. The height of the various implant systems' external hexagon ranged from 0.69 to 0.81 mm. The height of the Procera abutment blanks was 0.90 mm. Radiographic examination demonstrated that not all of the manufacturers' screws fit appropriately within the internal screw bore of the Procera abutment. The internal bore of all implant systems studied had a metric thread designation of M2 x 0.4 - 6H. The metric thread designation of all abutment screws examined was M2 x 0.4 - 6g. The greatest variations in the dimensions of the abutment screws measured were seen in the diameter of the screw head, which ranged from 2.12 to 2.69 mm. DISCUSSION: The Procera abutment's internal hexagon fit the external hexagon of all implant systems evaluated. The Procera abutment screw fit the internal screw bore of the implant systems tested. CONCLUSION: The Procera abutment with its screw can be universally applied to the implant systems studied. This fact, plus the CAD/CAM feature of this system, would thus provide a dynamic approach to satisfying the design and spatial needs of implant placements observed clinically.

A critically appraised topic review of computer-aided design/computer-aided machining of removable partial denture frameworks.

A critically appraised topic (CAT) review is presented about the use of computer-aided design (CAD)/computer-aided machining (CAM) removable partial denture (RPD) frameworks. A systematic search of the literature supporting CAD/CAM RPD systems revealed no randomized clinical trials, hence the CAT review was performed. A PubMed search yielded 9 articles meeting the inclusion criteria. Each article was characterized by study design and level of evidence. No clinical outcomes research has been published on the use of CAD/CAM RPDs. Low levels of evidence were found in the available literature. Clinical research studies are needed to determine the efficacy of this treatment modality.

Dental students' perceived level of competence in orofacial pain.

Orofacial pain (OFP) is a group of symptoms affecting a significant portion of the population; inadequate diagnosis and management of these symptoms present a potential detrimental effect on the public's health. It has been suggested that dental schools must prepare their graduates to deal with these problems rather than relying on their participation in continuing education courses after graduation. The aim of this study was to determine how third- and fourth-year students at one dental school perceived their level of competence related to OFP. Out of 140 students who were sent the survey, seventy-four (53 percent response rate) completed it in its entirety. The cross-sectional survey included questions regarding the students' familiarity with the categories of OFP. Questions asked how they perceived their knowledge in each of these areas, how comfortable they felt providing diagnosis and treatment, and if more knowledge was needed. The results showed that the fourth-year students were more comfortable than the third-year students in diagnosing and managing intraoral pain. Multiple comparisons also showed statistically significant differences between OFP categories for questions related to perceived knowledge, comfort in diagnosing and treating, and perceived need for more information. Overall, the students' perceived knowledge of and confidence in treating OFP varied with respect to certain categories, being lowest for psychogenic pain.

Immediate restoration of single tapered implants with nonoccluding provisional crowns: a 5-year clinical prospective study.

BACKGROUND: Dental literature has limited number of publications regarding long-term outcome data of immediate restoration of single missing teeth with an implant-supported provisional crown. PURPOSE: This 5-year study evaluated hard and soft tissue responses to the immediate placement of single implant-supported provisional crowns. MATERIALS AND METHODS: Twenty patients received one dental implant restored immediately with a provisional acrylic resin screw-retained crown. Crestal bone loss was evaluated from standardized periapical radiographs collected at 3-month intervals for the first 21 months followed by a 5-year evaluation. Historical controls acquired from available dental literature were used for comparison. RESULTS: One implant failed within 2 months of surgical placement, presenting with pain and mobility. The remaining implants demonstrated no infection, pain, or radiolucencies. Nineteen implants were clinically immobile, osseointegrated, and asymptomatic at 21 months. At 5 years, one patient died, three patients were noncompliant, and 15 implants were evaluated as functional. Mean bone loss (MBL) at 1 year and 21 months was approximately 0.5 ± 0.5 mm and 0.70 ± 0.26 mm at 5 years. There was no statistically significant difference between MBLs at p < 0.05. CONCLUSIONS: Immediate provisionalization of single dental implants compares favorably with conventional loading protocols. Long-term data suggest that immediate provisionalization of single dental implants is a viable treatment option.

Evidence-based dentistry and clinical implementation by third-year dental students.

Over the last two decades, the concept of evidence-based medicine (EBM) has become the standard of medical care. Defined by Sackett et al. as "the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients," EBM recognizes that the practitioner should combine individual clinical expertise with the best available external evidence for optimal care. Consideration of the patient's needs and preferences is also an integral component of the clinical application. Dental educators have to account for the fact that not all dental treatment outcomes have been researched with randomized clinical trials. Dogmas in dentistry still exist regarding restorative treatments and methods taught to next generations of practitioners, while limited evidence is available. The purpose of this study was to determine how third-year dental students at one U.S. dental school select articles to provide supportive evidence related to treatment planning. The results show that knowledge provided in a three-week course in evidence-based dentistry (EBD) for first-year dental students was not efficiently applied when the students reached their third year. A significant percentage of the students perceived the use of literature as not beneficial for sustaining clinical aspects of a treatment plan, and they did not use appropriate tools to access best available resources. As a result of these findings, the article proposes incorporation of specific learning objectives related to EBD principles throughout the curriculum and a simplified method to search for best available evidence that has the advantage of not requiring knowledge and training in rigorous formulation of clinical questions.

Maxillary zirconia implant fixed partial dentures opposing an acrylic resin implant fixed complete denture: a two-year clinical report.

The fabrication of fixed implant-supported prostheses for edentulous patients may be performed using all-ceramic or acrylic resin materials. This clinical report describes the fabrication and 2-year follow-up of maxillary zirconia implant fixed partial dentures opposing a mandibular acrylic resin screw-retained fixed complete denture.