Clinical outcomes of immediately loaded implant-supported overdentures: A long-term prospective clinical trial.

STATEMENT OF PROBLEM: Long-term evidence of immediate loading of dental implants with bar overdentures is lacking. PURPOSE: The purpose of this clinical study was to assess the clinical outcomes of immediate and conventional loading protocols of mandibular overdentures supported by 2 dental implants 14 years after initial placement. MATERIAL AND METHODS: Two groups of edentulous patients who received two TiUnite implants were enrolled in this study. In the experimental group (n=35), the implants were loaded immediately. In the control group (n=16), the conventional delayed loading protocol was followed. Participants of both the groups were treated with overdentures supported by a standardized resilient bar mechanism. Clinical oral health-related quality of life and patient satisfaction outcomes were recorded for 14 years after initial placement of implants and measured at various stages of treatment. RESULTS: Significant improvements in all outcomes were observed in both the groups compared with baseline, and this improvement was sustained over the duration of the study. No differences were noted in any of the study outcomes between the 2 groups. CONCLUSIONS: Both the loading approaches provide comparable short- and long-term results. The results of this study confirm that immediate loading of implant-supported overdentures is a predictable treatment approach. Future studies should focus on assessing long-term clinical outcomes with mandibular overdentures in nonsplinted applications.

Effect of Alumina Particle Size on the Bond Strength between Autopolymerized Acrylic Resin and Commercially Pure Titanium.

PURPOSE: To address the following null hypothesis: when the Rocatec bonding system is used, the various sizes of aluminum oxide particles used to roughen the surface area of the commercially pure (CP) titanium prior to bonding to autopolymerized resin have no effect on the average shear bond strength. MATERIALS AND METHODS: One hundred specimens were randomly allocated to five equally sized groups: Ti-no air abrasion (group A), Ti-air-abraded with 50 µm (group B), Ti-110 µm (group C), Ti-250 µm (group D), and Co-Cr-50 µm (group E) grain-size aluminum oxide. Rocatec Plus tribochemical coating was applied to all of the specimens, followed by a RelyX primer and Sinfonyopaquer. Autopolymerized denture base resin was then bonded to the treated titanium surfaces. All specimens underwent thermocycling (10,000 cycles), shear bond testing, and mode of failure examination under stereoscopic microscopy. RESULTS: The average bond strength of group D (250 µm) was significantly different compared to all other groups, except group C (p = 0.057, trending significance). The average bond strength of group D was substantially higher than that in the other groups (p < 0.01). The weakest bond was observed when the specimens did not receive any air abrasion (group A). Maximum load (N) showed the same significant results as the shear bond strength at maximum load (MPa). The average extension at maximum load (mm) and the time at maximum load(s) for group A were significantly different than that of all other groups. Group A had lower average values than any other group (p = 0.003). More cohesive and mixed, rather than adhesive, modes of failure were observed as the size of the aluminum oxide particles increased. CONCLUSION: When the Rocatec system is used, using a combination of chemical and micromechanical adhesion is essential for the success of the bond between the autopolymerized acrylic resin and CP Ti. The micromechanical interlock can be improved significantly when the Ti surface is air abraded with larger particles (250 µm) than the currently used alumina particle size.

Internal Adaptation of Implant-Supported, Polymer-Infused Ceramic Crowns Fabricated by Two CAD/CAM Systems.

PURPOSE: The aim of this in vitro study was to compare the internal 3D adaptation of polymer-infused ceramic crowns fabricated using two CAD/CAM systems: CEREC inLab MC XL and Ceramill Motion 2 (5X). MATERIALS AND METHODS: Twenty-five implant-supported metal-ceramic crowns were fabricated conventionally using the lost-wax technique, and the outer contour was scanned to serve as a guide for designing the polymer-infused ceramic CAD/CAM crowns. Twenty-five crowns were fabricated using CEREC, and 25 crowns were fabricated using Ceramill. The cement space was set to 20 µm. The Zeiss Accura Microsystem Coordinate Measuring Machine (CMM), Calypso, and Geomagic software were used to measure the 3D accuracy of fit of all crowns to their respective implant abutments. To test for the statistical significance between groups in terms of 3D total distortion, a one-way ANOVA was conducted. The Kolmogorov-Smirnov test was used to investigate the differences in the x, y, and z coordinates. A p-value of 0.05 or less was considered statistically significant at an alpha level of 0.05. RESULTS: Comparing the 3D misfit of metal-ceramic crowns to those of CAD/CAM crowns fabricated using CEREC revealed no significant difference (88.20 ± 36.59 µm vs. 102.45 ± 36.58 µm, p = 0.161). Similarly, no significant difference in 3D total distortion was identified between metal-ceramic crowns and crowns fabricated using Ceramill (88.20 ± 36.59 µm vs. 78.40 ± 31.03 µm, p = 0.336); however, the 3D total distortion of polymer-infused crowns made by Ceramill was significantly reduced compared to that of crowns fabricated by CEREC (78.3 ± 31.0 µm vs. 102.4 ± 36.5 µm, p = 0.019). CONCLUSIONS: Polymer-infused ceramic crowns fabricated using CEREC exhibited the least accurate 3D fit. All misfit values of the tested groups were within clinically acceptable levels.

Revised, Computed Tomography-Based Lekholm and Zarb Jawbone Quality Classification.

PURPOSE: To propose a revised Lekholm and Zarb classification that takes into account all possible combinations of compact and trabecular bone and to provide guidelines for increased reproducibility of the classification. MATERIALS AND METHODS: Three new classes were added to the previous classification. The new classes have been designated as subclasses of bone types 2 and 3, as follows: Type 2b: Thick layer of compact bone surrounding a core of medium-density trabecular bone; Type 2c: Thick layer of compact bone surrounding a core of low-density trabecular bone; and Type 3b: Thin layer of compact bone surrounding a core of medium-density trabecular bone. Three interpretation guidelines were recommended to increase the reproducibility of the revised classification. Three experienced examiners were trained using the revised classification and provided with computed tomography (CT) sectional images of edentulous jawbones for classification. Each examiner classified the images twice with at least a 1-week interval. The intra-observer agreement was measured. RESULTS: The kappa statistic for the intra-observer agreement of the examiners ranged from 0.835 to 0.919 (P < .001). CONCLUSION: The high reproducibility of the proposed revised CT-based Lekholm and Zarb classification obtained in the current study suggests its efficacy in distinguishing between the various combinations of compact and trabecular bone.

Current Evidence on Dental Implants Outcomes in Smokers and Nonsmokers: A Systematic Review and Meta-Analysis.

This systematic review aims to answer the following PICO (Participants, Intervention, Comparison, and Outcome) question: "Does smoking increase the rates of implant failure and peri-implant marginal bone loss in patients with dental implants?" An extensive electronic search of the Cochrane Central Register of Controlled Trials, PubMed, Medline, Embase, and Web of Science databases and a subsequent hand search were performed. Only randomized controlled trial, controlled clinical trials, and prospective studies published up to January 2017 were included. For dichotomous outcomes, the effect estimates for smoking are expressed as odds ratios and 95% CIs. For continuous outcomes, weighted mean differences (WMDs) and 95% CIs are presented. Three randomized controlled trials and 7 prospective studies were included. The odds ratio for implant failure among smokers was 2.92 (95% CI, 1.76-4.83) ( P < .001). First-year marginal bone loss in smokers ranged from 0.02 to 0.45 mm. In the nonsmokers, bone loss ranged from -0.08 to 0.42 mm. Nonsmokers lost significantly less bone during the first year (WMD = 0.11 mm, 95% CI. 0.03-0.19) and subsequent years (WMD = 0.11 mm, 95% CI, 0.03-0.19, P = .009). The available scientific evidence suggests that smoking is associated with significantly increased rates of implant failure and marginal bone loss.

Accuracy of computer-aided design models of the jaws produced using ultra-low MDCT doses and ASIR and MBIR.

PURPOSE: To compare the surface of computer-aided design (CAD) models of the maxilla produced using ultra-low MDCT doses combined with filtered backprojection (FBP), adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) reconstruction techniques with that produced from a standard dose/FBP protocol. METHODS: A cadaveric completely edentulous maxilla was imaged using a standard dose protocol (CTDIvol: 29.4 mGy) and FBP, in addition to 5 low dose test protocols (LD1-5) (CTDIvol: 4.19, 2.64, 0.99, 0.53, and 0.29 mGy) reconstructed with FBP, ASIR 50, ASIR 100, and MBIR. A CAD model from each test protocol was superimposed onto the reference model using the 'Best Fit Alignment' function. Differences between the test and reference models were analyzed as maximum and mean deviations, and root-mean-square of the deviations, and color-coded models were obtained which demonstrated the location, magnitude and direction of the deviations. RESULTS: Based upon the magnitude, size, and distribution of areas of deviations, CAD models from the following protocols were comparable to the reference model: FBP/LD1; ASIR 50/LD1 and LD2; ASIR 100/LD1, LD2, and LD3; MBIR/LD1. The following protocols demonstrated deviations mostly between 1-2 mm or under 1 mm but over large areas, and so their effect on surgical guide accuracy is questionable: FBP/LD2; MBIR/LD2, LD3, LD4, and LD5. The following protocols demonstrated large deviations over large areas and therefore were not comparable to the reference model: FBP/LD3, LD4, and LD5; ASIR 50/LD3, LD4, and LD5; ASIR 100/LD4, and LD5. CONCLUSIONS: When MDCT is used for CAD models of the jaws, dose reductions of 86% may be possible with FBP, 91% with ASIR 50, and 97% with ASIR 100. Analysis of the stability and accuracy of CAD/CAM surgical guides as directly related to the jaws is needed to confirm the results.

Do Ultra-Low Multidetector Computed Tomography Doses and Iterative Reconstruction Techniques Affect Subjective Classification of Bone Type at Dental Implant Sites?

PURPOSE: To investigate whether ultra-low-dose multidetector computed tomography (MDCT) combined with the reconstruction techniques filtered backprojection (FBP), adaptive statistical iterative reconstruction (ASIR), or model-based iterative reconstruction (MBIR) alters the subjective classification of revised Lekholm and Zarb (LZ) bone types at prospective dental implant sites. MATERIALS AND METHODS: Three cadavers underwent a reference MDCT examination using a standard dose volume (CT dose index [CTDIvol]: 29.4 mGy) and reconstructed with FBP in addition to five test protocols (LD1-LD5) using ultra-low doses (CTDIvol: 4.19, 2.64, 0.99, 0.53, and 0.29 mGy, respectively) and reconstructed with FBP, ASIR 50, ASIR 100, and MBIR. Transverse cross-sectional images of the jawbones were obtained, and three examiners subjectively classified the bone type in each image using the revised LZ classification. The bone type classifications obtained using the reference examination were compared with those obtained from the test protocols for each examiner, and kappa statistic was used to analyze the level of agreement between the reference and test protocols. The clinical significance of the differences was analyzed with Wilcoxon signed rank test. RESULTS: Examiners 1 and 2 found moderate to strong agreement between the reference and test protocols, while Examiner 3 found strong to almost perfect agreement (P < .001). The Wilcoxon signed rank test did not demonstrate a clinical significance of the differences between the reference and test protocols for any of the three examiners. CONCLUSION: MDCT dose reductions of up to 99% did not significantly alter the subjective classification of bone at dental implant sites.

Comparison of Clinical, Radiographic, and Immunologic Inflammatory Parameters around Crestally and Subcrestally Placed Dental Implants: 5-Year Retrospective Results.

PURPOSE: To compare changes in clinical (bleeding on probing [BOP] and probing pocket depth [PPD]), radiographic (crestal bone loss [CBL]), and immunologic inflammatory (interleukin-1beta [IL-1ß] and matrix metalloproteinase-9 [MMP-9]) parameters around crestally and subcrestally placed dental implants 5 years after implant placement. MATERIALS AND METHODS: Fifty-two patients were divided into 2 groups: group 1 (n = 27): patients with single implants placed approximately 2 mm below the alveolar crest; group 2 (n = 25): patients with single implants placed at bone level. In both groups, peri-implant BOP, PPD, and CBL were measured, and levels of IL-1ß and MMP-9 were determined in duplicates using enzyme-linked immunosorbent assay. Full-mouth debridement was performed biannually in both groups. Statistical analysis was performed using the Mann-Whitney U test (significance set at p < 0.05). RESULTS: All measurements in groups 1 and 2 were performed 5.3 ± 0.2 and 5.2 ± 0.1 years after implant placement, respectively. The mean CBL was 1.2 ± 0.2 mm and 1.4 ± 0.2 mm in groups 1 and 2, respectively. There was no significant difference in mean BOP, PPD, CBL and in levels of IL-1ß, and MMP-9 among implants in both groups. CONCLUSION: Clinical, radiographic, and immunologic inflammatory parameters are comparable around crestally and subcrestally placed single dental implants up to 5 years after placement. The depth of implant placement appears to have no effect on clinical status and performance of single dental implants.

Two-Implant-Supported Mandibular Overdentures: Do Clinical Denture Quality and Inter-Implant Distance Affect Patient Satisfaction?

PURPOSE: To investigate the following three null hypotheses in patients rehabilitated with a mandibular overdenture supported by two unsplinted implants: (1) patient satisfaction is not related to the clinical quality of the dentures; (2) inter-implant distance (IID) has no effect on the clinical quality of the dentures; and (3) IID does not influence patient satisfaction. MATERIALS AND METHODS: Forty edentulous patients who were rehabilitated with a two-implant-supported mandibular overdenture participated in the study. Independent investigators evaluated the dentures on the basis of five clinical criteria using the validated Denture Quality Evaluation Form, and the patients completed the validated Denture Satisfaction Scale. Irreversible hydrocolloid impressions of the mandible were made and poured immediately in die stone. The IID was measured by adapting an orthodontic wire to the mandibular alveolar ridge crest, extending from the center of one implant to the center of the other. Spearman correlation analyses were used to identify possible correlations, with a significance level set at P < .05. RESULTS: The clinicians' overall mean rating of the clinical quality of the dentures was 91.5% (standard deviation 6.27%). The stability of the mandibular overdenture and of the maxillary conventional complete denture was significantly related to satisfaction (r = 0.389 and r = 0.44, respectively). Significant associations were found between the mandibular stability items and satisfaction with both maxillary and mandibular dentures. The stability of the maxillary denture was significantly associated with patient satisfaction with mandibular denture retention, stability, and comfort. None of the 12 denture satisfaction items were significantly associated with IID. Similarly, IID did not have an effect on the quality of either denture in terms of retention, stability, or occlusion. CONCLUSION: Denture stability was the feature that had the most influence on patient satisfaction with the mandibular overdenture and with the maxillary conventional denture. IID had no effect on the clinical quality of either denture and did not influence patient satisfaction.

Cost minimization analysis of a long-term randomized clinical trial of patients treated with immediately loaded implant-supported fixed prosthesis.

PURPOSE: To document the long-term costs from a randomized controlled clinical trial (RCT) on edentulous patients treated with mandibular 4-implant-supported fixed prosthesis and two loading protocols. METHODS: Taking the perspective of the individual patient, costs associated with treatment, complications, and patients' time from 18 patients who received an immediate-loading protocol and 21 patients treated with a conventional loading protocol were compared over 10 years of observation. All costs are in Canadian dollars and discounted to the RCT base year of 2006 at a rate of 1.5%. RESULTS: The complication rate in both arms was similar and relatively low. No statistically significant difference was observed in the total cost and discounted total cost, along with its five comprising parameters between the two arms. CONCLUSIONS: Over the 10-year time frame, the immediate loading of dental implants with mandibular fixed prosthesis proved to cost similar to the conventional loading protocol, underscoring the feasibility and reliability of this protocol from the patient's perspective. (REB protocol reference # 33395).

Comparison of Clinical, Radiographic, and Immunologic Inflammatory Parameters Around Dental Implants with Cement-Retained and Screw-Retained Restorations: A 5-Year Prospective Cohort Study in Men.

PURPOSE: To compare bleeding on probing (BoP), probing depth (PD; ≥ 4 mm), radiographic (peri-implant crestal bone loss [CBL]), and immunologic inflammatory (interleukin-1beta [IL-1ß] and matrix metalloproteinase-9 [MMP-9]) parameters around dental implants with cement-retained (CR) and screw-retained (SR) implant-supported crowns. MATERIALS AND METHODS: Based on the mode of retention of the restoration, 51 patients were divided into two groups: Group 1, consisting of 26 single implants restored with CR crowns, and Group 2, consisting of 25 single implants restored with SR crowns. Peri-implant BoP, PD, and CBL were scored, and levels of IL-1ß and MMP-9 in the peri-implant crevicular fluid (PICF) in both groups were measured in duplicate using enzyme-linked immunosorbent assay. Full-mouth mechanical debridement was performed biannually in both groups. Statistical analysis was performed using Kruskal-Wallis test with the significance level set at P < .05. RESULTS: The mean CBL among implants in groups 1 and 2 was 1.7 ± 0.5 mm and 1.7 ± 0.4 mm, respectively. There was no statistically significant difference in mean BoP, PD, and CBL among implants in both groups (P > .05). There was no statistically significant difference between groups 1 and 2 in the PICF levels of IL-1ß (7.3 ± 0.5 and 7.2 ± 0.5, respectively) and MMP-9 (165 ± 9.4 and 182 ± 10.6, respectively) (P > .05). CONCLUSION: The mode of retention of implant-supported crowns does not appear to affect their clinical correlations with BoP, PD, CBL, and levels of IL-1ß and MMP-9 in the PICF when zinc oxide eugenol cement is used.

A cost analysis of a long-term prospective study of patients treated with immediately loaded implant-supported mandibular overdentures.

BACKGROUND: The economic burden for patients seeking treatment with implant-supported prostheses has not been given adequate attention. PURPOSE: To document long-term costs from a prospective trial on edentulous patients treated with mandibular implant-supported overdentures and 2 loading protocols. MATERIALS AND METHODS: The direct clinical and time costs for 35 patients receiving an immediate-loading protocol (ILP) and 40 patients with a conventional-loading protocol, over 14 years of observation, were analyzed in 2016 Canadian dollars as a base year. Quality of life (QoL) for the ILP was measured using the OHIP-20 questionnaire. RESULTS: The ILP was associated with higher complication costs ($870.77 ± 692.24 vs $85.73 ± 133.14) with resultant higher maintenance costs ($1746.37 ± 892.68 vs $853.04 ± 276.21) (P < .05). OHIP results showed a sustained improvement in QoL through the first 5 year of follow-up. A worsening of QoL, specifically the functional-related OHIP scores, was noted at 14 years. Incremental cost-effectiveness ratios indicated that the accrued maintenance costs for the ILP made the treatment less cost-effective over time. CONCLUSIONS: This long-term study confirmed that ILP is associated with higher maintenance costs and varying subjective QoL measurements. Clinical treatment protocols should be evaluated over a long period and address different perspectives.

A clinical investigation of the relationship between the quality of conventional complete dentures and the patients' quality of life.

OBJECTIVE: The purpose of this study was to determine whether there is a correlation between the clinical quality of conventional complete dentures and patient quality of life. MATERIALS AND METHODS: This study included a random sample of 32 completely edentulous patients (15 males and 17 females) who were treated with conventional complete dentures. Using a validated questionnaire, three investigators evaluated the dentures independently on the basis of seven clinical parameters: esthetics (lip support and lower lip line), retention and stability of the maxillary and the mandibular dentures, and occlusion. Patients completed the validated Oral Health Impact Profile-20 (OHIP-20) questionnaire. Correlations were determined by using the point-biserial correlation coefficient. RESULTS: Clinicians rated the overall clinical quality of the dentures satisfactory in 80.3% of patients. The mean (±standard deviation) total OHIP-20 score was 56.3 ± 15.9 out of a possible 120 maximum. A statistically significant negative correlation was found between the stability of the maxillary and mandibular dentures and the total OHIP-20 score (p = 0.009 and 0.0023, respectively). A negative correlation between the total OHIP-20 score and the retention of the mandibular denture approached significance (p = 0.092). Esthetics, retention of the maxillary denture, and occlusion were not correlated with patient quality of life (p > 0.169). CONCLUSION: Stability of the maxillary and mandibular dentures is the denture quality parameter that can most significantly affect patient quality of life.

Vertical marginal gap evaluation of conventional cast and computer numeric controlled-milled titanium full-arch implant-supported frameworks.

PURPOSE: To use a novel approach to measure the amount of vertical marginal gap in computer numeric controlled (CNC)-milled titanium frameworks and conventional cast frameworks. MATERIALS AND METHODS: Ten cast frameworks were fabricated on the mandibular master casts of 10 patients. Then, 10 CNC-milled titanium frameworks were fabricated by laser scanning the cast frameworks. The vertical marginal gap was measured and analyzed using the Contura-G2 coordinate measuring machine and special computer software. RESULTS: The CNC-milled titanium frameworks showed an overall reduced mean vertical gap compared with the cast frameworks in all five analogs. This difference was highly statistically significant in the distal analogs. The largest mean gap in the cast framework was recorded in the most distal analogs, and the least amount was in the middle analog. CONCLUSIONS: Neither of the two types of frameworks provided a completely gap-free superstructure. The CNCmilled titanium frameworks showed a significantly smaller vertical marginal gap than the cast frameworks.

The relationship between various parameters of complete denture quality and patients' satisfaction.

BACKGROUND: Patients' appreciation of their conventional complete dentures might be affected by the quality of the dentures. METHODS: A random sample of 33 edentulous patients who were rehabilitated by means of conventional complete dentures participated in the study. Three independent investigators who underwent technique calibration evaluated the dentures on the basis of seven clinical criteria by using a validated examination form. The patients filled out a validated denture satisfaction scale. The author used Pearson product-moment correlation and analysis of covariance to identify possible correlations. RESULTS: The study results showed that most patients were between "reasonably satisfied" and "very satisfied" with their dentures. The author found nominally higher satisfaction among those receiving both mandibular and maxillary dentures and significant positive correlations between the overall denture satisfaction score and the stability of the mandibular denture (P = .039) and retention of the mandibular denture (P = .005). In contrast, esthetic lip support and lower lip line, occlusion, and maxillary stability and retention were not correlated with participants' overall satisfaction level (P > .064). CONCLUSIONS: The results of this study show that a clinically stable mandibular denture was the most important determinant of patients' satisfaction. PRACTICAL IMPLICATIONS: The study findings highlight the most important denture quality parameters that can aid clinicians in meeting their patients' expectations.

A conservative and reversible approach for restoring worn teeth: a clinical report.

A 48-year-old man presented with worn dentition due to daytime bruxism. His chief concern was compromised esthetics due to short teeth. The occlusal vertical dimension was increased by 2 to 3 mm in the premolar area, and a maxillary titanium overdenture with composite resin facings was fabricated to address his concern. The advantages of this treatment, as opposed to complete coverage restorations, include preservation of tooth structure, lower cost, and shorter treatment time. Four years after insertion, the titanium overdenture continues to function successfully and to address the patient's concerns.

Five-year clinical results of immediately loaded dental implants using mandibular overdentures.

PURPOSE: The aim of this report is to present the clinical and patient-based outcomes of an immediate-loading protocol of TiUnite implants with mandibular overdentures in edentulous patients 5 years following initial placement. MATERIALS AND METHODS: The study comprised two groups of edentulous patients. In the experimental group, 35 consecutively treated patients received 70 TiUnite implants that were loaded immediately, as well as 69 Branemark machined implants as a backup treatment. One patient received one Branemark implant. The control group comprised patients who were treated previously with conventional two-stage implant procedures, but were all case matched to the intervention group and served as a historical cohort. This group included 42 patients who received 111 Branemark implants. Both groups of patients were treated with overdentures that were supported with a standardized resilient bar mechanism. Clinical and patient-based outcomes in the immediate group were recorded for the first 5 years following the initial placement of implants and were measured at various stages of treatment using two questionnaires: the Denture Satisfaction Scale and the Oral Health Impact Profile (OHIP-20). RESULTS: Just over 98% of implants were found to be successful in both groups (Fisher exact test: P = 1.000). A statistically significant improvement in patients' total, mandibular, and functional satisfaction scores was found when comparing baseline data to the data obtained 5 years following loading in the experimental group (P < .001). There were no significant differences between the 1- and 5-year total, mandibular, and functional satisfaction scores, or between baseline and 5-year maxillary denture satisfaction scores. A statistically significant and positive correlation was found between baseline and 1-year maxillary satisfaction scores (P = .002). Any improvement in the patients' quality of life (QoL) was maintained during the first 5 years of loading. CONCLUSION: The results of this longitudinal study suggest that immediate loading of two dental implants by means of bar-retained mandibular overdentures is a predictable treatment option and leads to substantial improvement in patients' satisfaction and QoL. Importantly, this mirrors the outcomes found for patients subjected to the more commonly accepted two-stage implant procedure.