Search

Statement of Problem: One of the disadvantages of a cemented implant restoration is the potential difficulty of retrieving it. The restoration may be destroyed during removal., Purpose: The purpose of this retrospective clinical study was to assess the long-term survival rates of cemented posterior metal ceramic implant-supported prostheses (ISPs) with a metal screw access hole., Material and Methods: During a 12-year period, 274 cemented ISPs with an abutment screw access hole in the metal framework were assessed and served as the study group, and 119 conventional cemented ISPs (without access hole) served as the control group. Participants were followed every 6 months in the first year and once a year subsequently. Ceramic fracture, screw loosening, and refabrication were the prosthetic outcome parameters evaluated at the recall. The Pearson Chi square and Fisher exact test were used to compare the outcome parameters between the control and study groups., Results: A total of 1005 implants and 393 ISPs were evaluated. Ceramic fracture occurred in 6.6% of the ISPs (6.2% test and 7.6% control). Screw loosening occurred in 3.28% of the test group and 3.36% of the control group. Refabrication of ISPs was done in 2.79% of all restorations, (1.45% test and 6.72% control [P=.012])., Conclusions: Within the limits of this study, preparing cemented ISPs with a screw access hole in the metal framework improves ISP survival rates over time and lowers the cost of maintenance without increasing the risk for porcelain fracture or screw loosening., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Soft tissue shrinkage during the course of restoring dental implants may result in biological and prosthodontic difficulties. This study was conducted to measure the continuous shrinkage of the mucosal cuff around dental implants following the removal of the healing abutment up to 60 s. Individuals treated with implant-supported fixed partial dentures were included. Implant data--location, type, length, diameter and healing abutments' dimensions--were recorded. Mucosal cuff shrinkage, following removal of the healing abutments, was measured in bucco-lingual direction at four time points--immediately after 20, 40 and 60 s. anova was used to for statistical analysis. Eighty-seven patients (49 women and 38 men) with a total of 311 implants were evaluated (120 maxilla; 191 mandible; 291 posterior segments; 20 anterior segments). Two-hundred and five (66%) implants displayed thick and 106 (34%) thin gingival biotype. Time was the sole statistically significant parameter affecting mucosal cuff shrinkage around dental implants (P < 0.001). From time 0 to 20, 40 and 60 s, the mean diameter changed from 4.1 to 4.07, 3.4 and 2.81 mm, respectively. The shrinkage was 1%, 17% and 31%, respectively. The gingival biotype had no statistically significant influence on mucosal cuff shrinkage (P = 0.672). Time required replacing a healing abutment with a prosthetic element should be minimised (up to 20/40 s), to avoid pain, discomfort and misfit., (© 2015 John Wiley & Sons Ltd.)

Purpose: To assess whether splinting can counterbalance the detrimental effects of varying the crown-to-implant (C/I) ratio and crown height space (CHS) by decreasing nonaxial overload stresses., Materials and Methods: Three implants were inserted into a photoelastic block model. Two strain gauges were cemented onto the neck of each implant on the buccal and lingual aspects and provided a simultaneous direct reading of strain. Four groups of splinted cement-retained restorations with C/I ratios of 1:1, 1:1.5, 1:1.75, and 1:2 were used. CHSs were 10, 15, 17.5, and 20 mm, respectively. Fifteen static loadings were carried out simultaneously with 20-kg weights via a custom-built loading apparatus at 30° to the vertical axis., Results: Occlusal force application at 30° showed a statistically significant increase in both buccal (1,911.65 ± 110 vs 3,252.06 ± 150) and palatal (35.58 ± 7 vs 286.85 ± 15) microstrain values as the C/I ratio increased from 1:1 to 1:1.5 (P < .001). Force application at 30° in cases with C/I ratios of 1:1.75 and 1:2 resulted in fracture of the abutment screw followed by dislodgement of the crowns. Failures were noted at a CHS of 15 mm or greater., Conclusions: In this biomechanical mode, splinting does not prevent prosthetic failure when the CHS is 15 mm or greater. Vertical bone augmentation is highly recommended in cases with a CHS of 15 mm or greater., (Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose: To prospectively evaluate the outcome of dental implants placed in the post-traumatic anterior maxilla after ridge augmentation with cancellous freeze-dried block bone allografts., Materials and Methods: Patients presenting with a history of anterior dentoalveolar trauma with bony deficiencies in the sagittal (≥3 mm) and vertical (<3 mm) planes according to computed tomography were included. The recipient sites were reconstructed with cancellous bone block allografts. After 6 months of healing, implants were placed. The primary outcomes of interest were 1) bone measurements taken before grafting, at the time of implant placement, and at stage 2 operations; 2) implant survival; and 3) complications., Results: The sample was composed of 20 consecutive patients with a mean age of 25 ± 7 years. We used 28 cancellous allogeneic bone blocks, and 31 implants were inserted. Of the 31 implants, 12 were immediately restored. The mean follow-up was 42 ± 15 months. Graft and implant survival rates were 92.8% and 96.8%, respectively. Mean bone gain in the sagittal and vertical planes was 5 ± 0.5 mm horizontally and 2 ± 0.5 mm (P < .001). Successful restoration was achieved in all patients with fixed implant-supported prostheses. Soft tissue complications occurred in 7 patients (35%). Complications after cementation of the crowns were seen in 3 implants (9.6%). All implants remained clinically osseointegrated at the end of the follow-up examination. There was no crestal bone loss around the implants beyond the first implant thread., Conclusion: Cancellous block allograft can be used successfully for post-traumatic implant-supported restoration in the anterior maxilla., (Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose: The present study was designed to compare the long-term outcome and complications of cemented versus screw-retained implant restorations in partially edentulous patients., Materials and Methods: Consecutive patients with bilateral partial posterior edentulism comprised the study group. Implants were placed, and cemented or screw-retained restorations were randomly assigned to the patients in a split-mouth design. Follow-up (up to 15 years) examinations were performed every 6 months in the first year and every 12 months in subsequent years. The following parameters were evaluated and recorded at each recall appointment: ceramic fracture, abutment screw loosening, metal frame fracture, Gingival Index, and marginal bone loss., Results: Thirty-eight patients were treated with 221 implants to support partial prostheses. No implants during the follow-up period (mean follow-up, 66 ± 47 months for screw-retained restorations [range, 18 to 180 months] and 61 ± 40 months for cemented restorations [range, 18 to 159 months]). Ceramic fracture occurred significantly more frequently (P < .001) in screw-retained (38% ± 0.3%) than in cemented (4% ± 0.1%) restorations. Abutment screw loosening occurred statistically significantly more often (P = .001) in screw-retained (32% ± 0.3%) than in cement-retained (9% ± 0.2%) restorations. There were no metal frame fractures in either type of restoration. The mean Gingival Index scores were statistically significantly higher (P < .001) for screw-retained (0.48 ± 0.5) than for cemented (0.09 ± 0.3) restorations. The mean marginal bone loss was statistically significantly higher (P < .001) for screw-retained (1.4 ± 0.6 mm) than for cemented (0.69 ± 0.5 mm) restorations., Conclusion: The long-term outcome of cemented implant-supported restorations was superior to that of screw-retained restorations, both clinically and biologically.

Purpose: To measure the transfer of axial and nonaxial load in unsplinted fixed implant supported restoration with varying crown to implant (C/I) ratios and crown height space (CHS)., Materials and Methods: A photoelastic block model was constructed. Three holes were drilled vertically in a straight line in the mid axis of the photoelastic model at predetermined locations to lengths of 12 mm. Three implants were inserted into the model. Two strain gauges were cemented onto the neck of each implant on the buccal and lingual aspects, which provided a simultaneous direct reading of strain. Four groups of cement retained restorations with C/I ratios of 1:1; 1:1.5; 1:1.75, and 1:2 were used. CHS were 10, 15, 17.5, and 20 mm, respectively. Fifteen static loadings were carried out simultaneously with 20 kg weights via a custom-built loading apparatus at 0 and 30 degrees to the vertical axis. Descriptive analysis consisted of mean and standard deviation of microstrain values for each group. Groups were compared by the use of the 1-way parametric analysis of variance. A P value of less than .05 was considered statistically significant., Results: Occlusal force application at 30 degrees showed a statistically significant increase in both buccal (1,588 ± 150 vs 2,610.59 ± 150) and palatal (64.92 ± 7 vs 146.59 ± 15) microstrain values as C/I ratio increased from 1:1 to 1:1.5 (P < .001). Force application at 30 degrees in cases with C/I ratio of 1:1.75 and 1:2 resulted in fracture of the abutment screw followed by dislodgment of the crowns. Failures were noted at CHS >15 mm., Conclusions: CHS is more significant than the C/I ratio in assessing biomechanical-related detrimental effects. Prosthetic failure occurred at CHS ≥ 15 mm., (Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Objective: The aim of this long-term study was to compare the need for prosthetic aftercare of direct vs. indirect attachment incorporation techniques to mandibular implant-supported overdenture., Materials and Methods: Forty-five consecutive patients were included (130 implants were placed). Treatment was randomly allocated, resulting in 22 patients (group A) to be treated with direct ball attachment incorporation and 23 patients (group B) to be treated with indirect ball attachment incorporation. All patients were treated by experienced oral-maxillofacial surgeons/periodontists and experienced prosthodontists/residents. From the first day that the patients visited the clinic up to 20 years after the first treatment session, all surgical or prosthetic therapeutic interventions were recorded. The recorded data for the present study included the number of aftercare visits and dental treatment received (pressure sores relieve, liner changes due to loss of retention and attachment replacement due to wear)., Results: The mean follow-up was 93±57 months. No implants were lost. Statistical analysis revealed a statistically significantly (P<0.001) greater need for prosthetic interventions in group B vs. group A. The mean number of visits dedicated to - pressure sores relieve (7.04±1.4 vs. 3.63±0.84); liner exchange due to loss of retention (3.6±1.3 vs. 1.09±1.06) was significantly higher in group B. Attachment replacement due to wear occurred only in group B (11/23 - 47.8%)., Conclusion: The direct technique for attachment incorporation in mandibular implant-supported overdentures using ball attachments is superior to the indirect technique from the aftercare perspective during a long-term evaluation period., (© 2010 John Wiley & Sons A/S.)

Background and Objective: Patients with congenitally missing teeth may present with undeveloped alveolar bone morphology, making implant reconstruction a challenge. The aim of the present study was to evaluate the outcome of dental implants after ridge augmentation with cancellous freeze-dried block bone allografts in patients with congenitally missing teeth., Study Design: Twelve patients with a mean age of 21 ± 4 years, were included. Congenitally missing teeth included maxillary lateral incisors, a maxillary canine, and mandibular central and lateral incisors. A bony deficiency of ≥3 mm horizontally and ≤3 mm vertically according to computerized tomography served as inclusion criteria. Twenty-one implants were inserted after a healing period of 6 months. Five out of 21 implants were immediately restored. Bone measurements were taken before bone augmentation, during implant placement, and at second-stage surgery., Results: Nineteen cancellous allogeneic bone-blocks were used. The mean follow-up time was 30 ± 16 months. Bone block and implant survival rates were 100% and 95.2%, respectively. Mean bone gain was statistically significant (P < .001): 5 ± 0.5 mm horizontally and 2 ± 0.5 mm vertically. All of the patients received a fixed implant-supported prosthesis. Soft tissue complications occurred in 4 patients (30%). Complications after cementation of the crowns were seen in 1 implant (4.8%). All implants remained clinically osseointegrated at the end of the follow-up examination. There was no crestal bone loss around the implants beyond the first implant thread., Conclusion: Cancellous bone block-allografts can be used successfully for implant-supported restorations in patients with congenitally missing teeth., (Copyright © 2011 Mosby, Inc. All rights reserved.)

This study aimed at determining whether the individual's chewing side preference is affected by local effects, produced by the presence of implant-supported restorations. The test group included 81 patients with partial implant-supported prosthesis. The control group included 108 subjects with no implants. All subjects went through a series of laterality tests for chewing and tasks (hand, foot, eye and ear) side preference. The preferred chewing side (PCS) was determined by observing the first stroke of the chewing cycle during chewing a gum. A positive and significant correlation between the chewing side preference and the subject's sidedness during the different tasks was examined, by performing four Phi correlation tests for: chewing and handedness(r = 0·54; P < 0·001); chewing and footedness (r = 0·49; P < 0·001); chewing and eyedness (r = 0·65; P < 0·001) and chewing and earedness (r = 0·66, P < 0·001). Of the subjects, 78·3% preferred the right side for chewing, 19·1% preferred the left and 2·1% had no clear side preference. There was no statistical difference in chewing side preference distribution between genders. The distribution of chewing side preference was not significantly affected by the location of missing teeth or implants. In conclusion, implant placement will not affect PCS. Therefore, information on chewing side preference should be part of the routine preoperative examination for implant-supported restorations to provide a better treatment plan in those cases that the implant-supported restoration will be on the PCS., (© 2010 Blackwell Publishing Ltd.)

Controversy remains over the rehabilitation of implant-supported restorations regarding the need to splint adjacent implant-supported crowns. This study compared the effects of simulated occlusal loading of three implants restored with cemented crowns, splinted versus unsplinted. Three adjacent screw-shaped implants were passively inserted into three holes drilled in a photo-elastic model. Two combinations of cemented restorations were fabricated; three adjacent unsplinted and three adjacent splinted crowns. Strain gauges were connected to the implant necks and to the margins of the overlaying crowns. Fifteen axial static loads of 20-kg loadings were carried out right after each other via a custom-built loading apparatus. Strain gauges located on the implant neck supporting splinted restoration demonstrated significantly (P < 0.001) more strain (sum of strains = 3348.54 microstrain) compared with the single crowns (sum of strains = 988.57 microstrain). In contrast, significantly (P < 0.001) more strain was recorded on the strain gauges located on the restoration margins of the single crowns (sum of strains = 756.32 microstrain) when compared with splinted restorations (sum of strains = 186.12 microstrain). The concept of splinting adjacent implants to decrease loading of the supporting structures may require re-evaluation. The clinical relevance of these findings needs further investigation.

Purpose: To review the published data on the treatment outcomes of restoring the partially edentulous patient with implant-supported removable partial dentures (ISRPDs) and describe the concept of ISRPDs and the clinical guidelines for placing implants for ISRPDs, and evaluate case series results., Materials and Methods: For the review, a literature search was performed using the PubMed and Ovid databases. Reports in English from 1969 to 2008 were considered. Also, 35 patients have had their dentition restored with ISRPDs supported by 67 implants. These patients were evaluated in terms of implant and teeth survival., Results: The data from the published reports and the presented case series suggest that the incorporation of dental implants into removable partial dentures could be an optional treatment plan for the partially edentulous patient to improve function and patient satisfaction., Conclusions: ISRPDs provide patients with stable, long-term predictable prostheses. This treatment alternative should be considered whenever fixed restorations are not a valid option. Strict maintenance and a follow-up protocol are recommended to obtain satisfactory results. Longitudinal clinical studies are required for evaluation of ISRPDs.

Purpose: To assess the clinical effectiveness of immediate nonfunctional loading for single-tooth implants placed in the anterior maxilla following augmentation with cancellous freeze-dried block graft., Materials and Methods: The clinical outcomes of immediately nonfunctionally loaded implants up to 18 months after placement in the anterior maxilla were evaluated in 11 consecutive patients. Implants were immediately restored with unsplinted acrylic resin provisional crowns. Follow-up was monthly, and intraoral radiographs were obtained immediately after implant placement and at 6, 12, and 18 months. Survival rate and radiographic marginal bone loss were evaluated at 0, 6, 12, and 18 months. In the anterior maxilla, 12 implants were placed., Results: Marginal bone loss did not extend beyond the first thread up to 18 months follow-up, and the survival rate was 100%., Conclusion: Within the limits of the present study, immediate nonfunctional loading for single-tooth implants placed in the anterior maxilla following augmentation with cancellous freeze-dried block graft seems a promising treatment alternative.