What is the optimal number of implants for fixed reconstructions: a systematic review

Comparison of fatigue lifetime of new generation CAD/CAM crown materials on zirconia and titanium abutments in implant-supported crowns: a 3D finite element analysis

OBJECTIVES

Due to the dynamic character of the stomatognathic system, fatigue life experiments simulating the cyclic loading experienced by implant-supported restorations are critical consideration. The aim of this study was to examine the effect of different crown and abutment materials on fatigue failure of single implant-supported crowns.

METHODS

Models were created for 10 different designs of implant-supported single crowns including two zirconia-reinforced lithium silicates (crystallized and precrystallized), monolithic lithium disilicate, polymer-infiltrated ceramic networks, and polyetheretherketone supported by zirconia and titanium abutments. A cyclic load of 179 N with a frequency of 1 Hz was applied on palatal cusp of a maxillary first premolar at a 30° angle in a buccolingual direction.

RESULTS

In the models with titanium abutments, the polymer-infiltrated ceramic network model had a lower number of cycles to fatigue failure values in the implant (5.07), abutment (2.30), and screw (1.07) compared to others. In the models with zirconia abutments, the crystallized zirconia-reinforced lithium silicate model had a higher number of cycles to fatigue failure values in the abutment (8.52) compared to others. Depending on the fatigue criteria, polyetheretherketone implant crown could fail in less than five year while the other implant crowns exhibits an infinite life on all models.

CONCLUSIONS

The type of abutment material had an effect on the number of cycles to fatigue failure values for implants, abutments, and screws, but had no effect on crown materials. The zirconia abutment proved longer fatigue lifetime, and should thus be considered for implant-supported single crowns.

Outcomes that may affect implant and prosthesis survival and complications in maxillary fixed prosthesis supported by four or six implants: A systematic review and meta-analysis

Objective

To investigate whether the clinical and radiographical outcomes are affected when four or six implants support the maxillary fixed complete denture (FCD).

Materials and methods

This study was registered on PROSPERO (CRD42021226432) and followed the PRISMA guidelines. The focused PICO question was, "For an edentulous maxillary patient rehabilitated with an implant-supported fixed prosthesis, do the clinical and radiographical outcomes differ when four or six implants support the prosthesis ". A thorough search of the relevant studies was designed and performed electronically. The survival rate of implant and prosthesis, marginal bone loss, and complications (mechanical and biological) were the primary outcomes, whereas implant distribution and using the surgical guide, follow-up, and framework material were evaluated as secondary outcomes.

Results

Out of 1099 articles initially retrieved, 53 clearly stated the outcomes of interest and were included in this study. There were no significant differences in implant and prosthesis survival, technical/mechanical complications, and biological complications between the 4-implant group (4-IG) and the 6-implant group (6-IG). However, marginal bone loss (MBL) was significantly higher in the 4-IG (p < 0.01). The surgical guide and follow-up period did not significantly affect implant/prosthesis survival. Additionally, using the CAD/CAM milled framework and anteroposterior implant distribution were associated with significantly higher implant survival in the 6-IG (p < 0.01).

Conclusion

The findings of this study indicated that having a greater number of implants, as seen in the 6-implant group, can lead to a decrease in technical and biological complications and reduce marginal bone loss. It is worth noting that factors such as using CAD/CAM frameworks and the anteroposterior distribution of implants were recognized as important in improving implant survival rates when more implants are present.

Prosthetic Rehabilitation of All-on-Six Implant-Supported Prosthesis: A Case Report

This clinical report explores the effectiveness of dental implants for rehabilitating fully edentulous arches, with a focus on the all-on-six treatment approach. Implant-supported fixed restorations, particularly using six implants, are presented as an expected and cost-effective solution for the rapid repair of the edentulous patient, avoiding the need for bone grafting. This report details the successful rehabilitation of a patient's completely edentulous arches using the all-on-six concept, highlighting the meticulous planning and execution involved. It concludes that precise diagnostic and implant planning, along with thorough attention to all the features, is crucial for successful implant-supported fixed prostheses, with the all-on-six concept offering improved clinical and radiological outcomes for atrophied maxillae.

Assessment of Various Risk Factors for Biological and Mechanical/Technical Complications in Fixed Implant Prosthetic Therapy: A Retrospective Study

The goals of this research were to determine the influence of several factors on implants' biological and technical complications in posterior fixed implant prosthetic therapy.

MATERIALS AND METHODS

The study group consisted of 67 edentulous patients (mean age: 63.88 ± 11.709 yrs; 20 males, 47 females) with implant prosthetic therapy for posterior edentulism. A total of 76 implant-supported fixed partial dentures (IP-FPDs) and 178 implants were assessed using clinical and paraclinical assessments. Risk factors for biological complications (peri-implantitis) and technical complications were determined by using the Pearson Chi-squared test and multivariate analysis.

RESULTS

The implant success (the absence of biological and mechanical/technical complications) was 66.30%. The prevalence of biological complications was 13.5%. The prevalence of technical complications was 28.70%. Variables that were associated with a higher risk of peri-implantitis were poor oral hygiene and bruxism. In univariate analysis, poor oral hygiene increased the risk of peri-implantitis 5.778 times and bruxism 5.875 times. Variables that were associated with a higher risk of mechanical/technical complications were age group > 60 yrs, smoking, history of periodontal disease, and bruxism. In univariate analysis, the risk of technical complications increased 4.14 times for patients in the age group > 60 years (vs. age group 40-60 years) and 20.5 times for patients with bruxism. Bruxism and smoking were significant predictors of mechanical/technical complications in the multivariate model.

CONCLUSIONS

In univariate models, patients with poor oral hygiene and bruxism have an increased risk of peri-implantitis. In multivariate models, we did not identify significant predictors of peri-implantitis. Age group > 60 yrs, smoking, history of periodontal disease, bone grafting, and bruxism are risk factors for the increase in the mechanical/technical complication rate. In the multivariate model, smoking and bruxism are significant predictors of the mechanical/technical complications.

Oral and Periodontal Risk Factors of Prosthetic Success for 3-Unit Natural Tooth-Supported Bridges versus Implant-Supported Fixed Dental Prostheses

The goals of this research are: (1) to compare the survival and prosthetic success of metal-ceramic 3-unit tooth- versus implant-supported fixed dental prostheses; (2) to evaluate the influence of several risk factors on the prosthetic success of tooth- and implant-supported fixed dental prostheses (FPDs). A total of 68 patients with posterior short edentulous spaces (mean age 61.00 ± 1.325 years), were divided into two groups: 3-unit tooth-supported FPDs (40 patients; 52 FPD; mean follow-up 10.27 ± 0.496 years) and 3-unit implant-supported FPDs (28 patients; 32 FPD; mean follow-up 8.656 ± 0.718 years). Pearson-chi tests were used to highlight the risk factors for the prosthetic success of tooth- and implant-supported FPDs and multivariate analysis was used to determine significant risk predictors for the prosthetic success of the tooth-supported FPDs. The survival rates of 3-unit tooth- versus implant-supported FPDs were 100% and 87.5%, respectively, while the prosthetic success was 69.25% and 68.75%, respectively. The prosthetic success of tooth-supported FPDs was significantly higher for patients older than 60 years (83.3%) vs. 40-60 years old (57.1%) (p = 0.041). Periodontal disease history decreased the prosthetic success of tooth- versus implant-supported FPDs when compared with the absence of periodontal history (45.5% vs. 86.7%, p = 0.001; 33.3% vs. 90%, p = 0.002). The prosthetic success of 3-unit tooth- vs. implant-supported FPDs was not significantly influenced by gender, location, smoking, or oral hygiene in our study. In conclusion, similar rates of prosthetic success were recorded for both types of FPDs. In our study, prosthetic success of tooth- versus implant-supported FPDs was not significantly influenced by gender, location, smoking, or oral hygiene; however, history of periodontal disease is a significant negative predictor of success in both groups when compared with patients without periodontal history.

The use of three implants to support a fixed prosthesis in the management of the edentulous mandible: a systematic review

BACKGROUND

Dental implants have been widely utilised as a treatment modality for prosthetic rehabilitation. The aim of this study was to evaluate the implant and prosthetic survival rate, changes in marginal bone level, and patient satisfaction outcomes with the use of three implants to support a fixed prosthesis in the edentulous mandible.

METHODS

A comprehensive electronic search was performed in the MEDLINE, Embase and Cochrane databases to retrieve studies that met the selection criteria. Sixteen articles were selected which consisted of two randomised controlled trials, eight prospective cohort studies, five retrospective studies and one case series.

RESULTS

A total of 2055 implants were placed in 685 patients with a mean age of 62.2 years. The mean cumulative implant survival rate was 96.2% over a mean follow-up period of 3.35 years. Mean marginal bone loss recorded was 1.25 mm and high patient satisfaction rates were reported across the studies.

CONCLUSION

The use of three implants to support a fixed prosthesis appears to be a successful approach to restoring the edentulous mandible in the short-to-medium term. Further longitudinal comparative studies are required to support longer-term success, and to guide minimum implant dimension requirements for the technique.

Case Series on the Long-Term Effect of Three Different Types of Maxillary Implant-Supported Overdentures on Clinical Outcomes and Complications

(1) Long-term data on maxillary implant overdentures (IODs) are scarce. This case series evaluated three types of IODs supported by six, four or three implants (Anyridge^®, Mega'Gen Implant Co., Ltd., Daegu, South-Korea), after 3-5 years in function. (2) A total of 31 patients, with 132 implants, were non-randomly allocated based on available bone or financial limitations. IOD-6 received a telescopic overdenture; IOD-4 a bar; and IOD-3, non-connected implants with locator abutments. Implant survival, bone level changes, probing pocket depth (PPD), plaque index, bleeding on probing (BOP), and technical, biological and aesthetic complications were registered. Impact of suprastructures on bone loss and PPD was analyzed using mixed-effect linear regression models. Differences between groups were analyzed using the ANOVA test for BOP, and Kruskal Wallis test for complications. (3) In total, 23 patients participated in the follow-up (9 female, 14 male), with average age of 62.2 years; 7, 11 and 5 patients in IOD-6, IOD-4 and IOD-3, respectively. Implant survival after 4.4 years on average, was 98% in total; 100%, 97.8% and 93.3% for IOD-6, IOD-4 and IOD-3, respectively. Mean bone loss corresponded to 0.68 mm (SD 1.06, range -4.57-1.51), 0.39 mm (SD 1.06, range -3.6-2.43), and 1.42 mm (SD 1.68, range -5.11-0.74) for IOD-6, IOD-4 and IOD-3, respectively. A statistically significant difference was seen in bone level when comparing IOD-6 to IOD-3 (p = 0.044), and IOD-4 to IOD-3 (p = 0.018). Mean PPD was 3.8 mm (SD: 0.69; range 2.5-5.3), 3.5 mm (SD 0.59; range 2.33-5), and 3.2 mm (SD 0.56; range 2-4) for IOD-6, IOD-4 and IOD-3, respectively, and differed significantly between IOD-6 and IOD-3 (p = 0.029). Incidence of peri-implantitis was 1%. No differences were seen for complications between groups. (4) Maxillary IOD supported by four to six implants is the most reliable treatment regarding implant survival and peri-implant health. More research is needed in the clinical outcomes, in particular the peri-implant health, and complications of maxillary IODs, especially with a reduced number of implants.

Rehabilitation of the Completely Edentulous Mandible by All-on-Four Treatment Concept: A Retrospective Cohort Study with Up to 10 Years Follow-Up

(1) Background and Objectives. Currently, there are no definitive long-term data about clinically significant difference in the failure of prosthesis and implant or marginal bone loss related to the rehabilitation of the completely edentulous mandible by all-on-four treatment concept. The main aim of present investigation was to report the long-term outcomes (10-years follow-up) of complete-arch mandibular rehabilitations based on the all-on-four concept. (2) Materials and Methods. Patients in need of extractions of teeth due to the occurrence of caries and/or severe periodontal disease and patients presented with edentulous mandibles were enrolled to the study. A total of 96 participants (mean follow-up period after intervention of 3185.2 days) were enrolled in the study. Participants were evaluated at the first visit, 10 days after intervention and every year after the intervention. Implant and prosthesis survival, bone loss and both local biological and mechanical complications were evaluated during the follow-up period. (3) Results. An implants’ survival rate of 97.9% was observed at the end of the follow-up period. Biological complications were reported in 19.8% of patients, whereas mechanical complications were reported in 27.1% of cases. The average marginal bone level at baseline was −0.03 mm. A significant marginal bone loss was observed after 10-years follow-up (2.5 mm). Binary logistic regression analysis showed significant association between smoke and both marginal bone loss and local biological complications. Lastly, a significant association was observed between bruxism and mechanical complications. (4) Conclusions. The high implant and prosthesis survival rate and the moderate incidence of biological and mechanical complications observed in present investigation can be associated to several factors such as high implant primary stability, prosthetic design, and control of the occlusal forces.

Radiographic Evaluation of Prosthodontic Patients

This article focuses on radiographic imaging with regard to planning, treating, and maintaining partially and completely edentulous prosthodontic patients with dental implants. Cone-beam computed tomography (CBCT) is the preferred imaging method for pretreatment dental implant treatment planning. Radiographic guides containing radiopaque materials and/or fiducial markers transfer both the proposed prosthesis design and desired implant location for appropriate radiographic evaluation. The three-dimensional CBCT analysis provides information on the adjacent relevant anatomy, bone volume of the edentulous sites, and restorative space assessment.

Clinical Behavior and Complications of Mandibular Full-Arch Fixed Dental Prostheses Supported by Three Dental Implants. A Systematic Review and Meta-Analysis

This systematic review and meta-analysis set out to assess the clinical behavior of mandibular implant-supported fixed complete dental prostheses (ISFCDP) on three dental implants by analyzing implant and prosthetic survival rates, marginal bone loss, biological/technical complications, and patient-reported outcomes. The review was conducted according to PRISMA guidelines. Electronic searches were conducted in the Medline (PubMed), Web of Science, and Cochrane databases, complimented by a manual search in specialist journals for relevant articles published up to February 2021. The Newcastle-Ottawa Quality Assessment Scale tool was used to assess the quality of evidence in the studies reviewed. The study included 13 articles with 728 patients treated with 2184 implants. A mean implant survival rate of 95.9% (95% CI: 94.6-97.3%) and a prosthetic survival rate of 97.0% (95% CI: 95.7-98.3%) were obtained over 1-6-year follow-up periods. Mandibular implant-supported fixed complete dental prostheses on three dental implants would appear to be a viable option for restoring the edentulous mandible in comparison with mandibular ISFCDP on more than three implants. Further comparative studies are needed, with adequate protocols, as well as sufficient sample sizes and follow-up periods to confirm these findings.

The influence of framework material on stress distribution in maxillary complete-arch fixed prostheses supported by four dental implants: a three-dimensional finite element analysis

The purpose of the present study was to compare the stress distribution patterns of four materials used for the framework of All-on-4 prostheses. Following framework materials were evaluated: PEKK, PEEK, titanium, and monolithic zirconia. Bilateral 150 N axial and oblique loads were applied in the first molar region and analyzed using FEA. The highest maximum principal stress and minimum principal stress values in cortical bone were found to appear with PEKK and PEEK frameworks around the posterior dental implants upon oblique loading. The fabrication of frameworks from rigid materials in All-on-4 prostheses reduces stress in dental implants and peri-implant bone when the distal implants are tilted 30°.

A digital approach to robust and esthetic implant overdenture construction

OBJECTIVE

Overdenture therapy is an important option for implant rehabilitation. However, numerous reports suggest that mechanical/technical complications and failures can limit therapeutic success. The goal of this report is to illustrate a digital approach to design and construction of a robust overdenture with high-esthetic value.

MATERIALS AND METHODS

Beginning with new denture design to establish esthetic parameters, 3D modeling of a metal framework and the denture teeth are completed in a connected manner. This enables connection of rapidly printed, prototype dentition that is attached directly to the framework without intervening wax or acrylic components. Following evaluation of the dentition and required adjustments, the final dentition is milled from resin and processed to the selective laser sintered framework.

RESULTS

The advantages of the digital workflow include the control of dimensions and strength of the framework, the esthetic relationship of the framework to the dentition and the facilitation of esthetic try-in of the dentition.

CONCLUSION

Enhancing a robust overdenture can be readily achieved using a digital workflow.

CLINICAL SIGNIFICANCE

The use of digital technology enables the clinical team to plan and produce prostheses with dimensions and contours that support long-term function and esthetics. The clinical chair time can be potentially reduced by use of digital design that facilitates try-in and reduces major errors by improved communication between the patient, dentist, and technician.

Prosthetic rehabilitation of a patient with cleidocranial dysplasia using dental implants-a clinical report

Adult patients with oral manifestations of untreated syndromic malformations usually exhibit a high degree of suffering. In this clinical report, we describe the implant-supported prosthetic treatment of a patient with cleidocranial dysplasia, a rare autosomal-dominant inherited malformation syndrome. Therapy for oral manifestations of cleidocranial dysplasia should be started in early childhood; however, the 26-year-old patient in the present study had not undergone orthodontic therapy in childhood. The treatment measures performed prior to this study were limited to the removal of several permanent teeth. Surgical pretreatment, placement of six implants each in the maxilla and mandible, and prosthetic restoration are described. The implantation was guided using a three-dimensional template. Long-term immediate temporary restoration and immediate loading of the implants were performed. The definitive prosthetic restoration was completed using fixed, acrylic resin-veneered screw-retained fixed dental prostheses. The clinical and radiological parameters observed in this case suggest that surgical and prosthetic procedure concepts from implantology can be adopted for patients with CCD.

Fixed full-arch maxillary prostheses supported by four versus six implants with a titanium CAD/CAM milled framework: 3-year multicentre RCT

OBJECTIVES

This RCT compares marginal bone level (MBL) change and the clinical parameters after a 3-year function in maxillary implant-supported fixed complete dentures (FCDs) treated with four-implants (4-I) or six-implants (6-I).

MATERIAL AND METHOD

Three centres treated 56 patients with 280 implants allocated to the 4-I or 6-I group. Radiographic and clinical examinations were performed. The primary outcome was to investigate MBL change between the groups.

RESULTS

Implant survival rates were 100% and 99% in the 4-I and 6-I groups, respectively. Considering the clustering effects, the MBL change was not significantly different between the groups over the 3-year follow-up. The MBL in the 4-I group was 0.30 ± 0.50 mm at baseline, 0.24 ± 0.31 mm at 1 year and 0.24 ± 0.38 mm at 3 years. In the 6-I group, MBL was 0.14 ± 0.32 mm at baseline, 0.16 ± 0.35 mm at 1 year and 0.12 ± 0.26 mm at 3 years. There was a statistically significant difference between the groups at BL and 3Y. No significant differences between the groups were reported for clinical parameters at each time point as well as in between the visits. The technical and biological complications rates were 1.6% and 6.0%, respectively. Prosthetic complications affected 25 FCDs (47.2%).

CONCLUSION

Marginal bone level change revealed a stable condition in the 3-year period in the two groups. Few technical and biological complications occurred apart from the chipping/fracture of the prosthetic teeth. Four-implant is a feasible solution if the rehabilitation is oriented towards the most cost-effective treatment and towards avoiding bone augmentation procedures. Clinicians have to consider the potential required visits for prosthetic maintenance.

Effect of sealing gel on the microleakage resistance and mechanical behavior during dynamic loading of 3 implant systems

STATEMENT OF PROBLEM

Sealing products have been produced to reduce microleakage at the implant abutment interface. However, little is known about their effectiveness and any alterations in mechanical behavior of implant systems with their application.

PURPOSE

The purpose of this in vitro study was to evaluate the effect of a silicone sealing gel on implant abutment interface microleakage, abutment screw torque loss, and thread wear of implant systems in a simulated oral environment.

MATERIAL AND METHODS

Five specimens each of 3 implants systems (Nobel, Straumann, and WEGO) that included sealed and unsealed groups were analyzed (N=30). Before assembling the components, toluidine blue solution was injected to the implant intaglio cavity to evaluate implant abutment interface microleakage. After tightening to the recommended torque, 20 to 200 N of 30-degree off-axis dynamic force was applied at 2 Hz for 48 hours. The toluidine blue solution was extracted to test optical density values at 1, 3, 9, 24, 33, and 48 hours. Detorque values were measured before and after cycling loading, and torque loss rates were calculated. The abutment screw morphologies were observed by using scanning electron microscopy. The coefficient of friction tendency of applying sealing gel was explored with a ball-on-flat configuration. One-way ANOVA and Student t test were used for statistical analysis (α=.05).

RESULTS

The optical density value increased with the loading time, especially for Straumann group. The sealing gel decreased the implant abutment interface microleakage of Straumann assemblies after cyclic loading of 9 hours (P=.044), whereas no statistical difference was found for Nobel (P=.140) or WEGO groups (P=.402) at 6 time points. Torque loss occurred during tightening and further increased after dynamic cyclic load in each group. Among the 3 implant systems, Straumann implants reported the best antiloosening property (P<.001). The application of sealing gel reduced the initial (P=.048) and final (P=.032) torque loss rate in all the 3 systems. Scanning electron microscopy observations revealed the bottom thread tended to have more abrasion than the first thread. After applying sealing gel, less thread abrasion was found in Nobel and WEGO assemblies, whereas the protective effect was not evident for the Straumann group. The coefficient of friction of sealed group (0.17 ±0.026) was significantly (P=.012) lower than that of unsealed group (0.24 ±0.044).

CONCLUSIONS

The silicone sealing gel improved the immediate fastening and long-term antiloosening performances of 3 implant systems, decreased the implant abutment interface microleakage of Straumann system, and reduced abutment screw thread abrasion of the Nobel and WEGO systems.

Trefoil System for the Treatment of Mandibular Edentulism: A Case Report with 30 Months Follow-Up

The purpose of this work is to describe a clinical case of full-arch mandible rehabilitation with a fixed prosthesis on three implants. The chosen protocol is the Trefoil system by Nobel (Nobel Biocare, Zurich, Switzerland) that allows to realize a mandibular fixed rehabilitation on three particularly designed fixtures through the use of prefabricated surgical guides and a preassembled bar on which the prosthesis is built. Both surgical and prosthetic procedures were completed without complications, and after 30 months, the rehabilitations are in good health conditions. The patient is able to maintain a good level of hygiene and is satisfied with the work from an aesthetic and functional point of view.

Retrospective study comparing the clinical outcomes of bar-clip and ball attachment implant-supported overdentures

The aim of this study was to compare the clinical outcomes of implant-supported overdentures (ODs) with either bar-clip or ball attachments. The implant, prosthesis failure, and technical complications were the outcomes analyzed in this retrospective clinical study conducted in a specialty clinic. Seventy-five patients with 242 implants supported by 76 ODs (36 maxillary, 40 mandibular) were included in the study and followed up for 88.8 ± 82.9 months (mean ± standard deviation). Bar-clip and ball attachments were used in 78.9% and 21.1% of the cases, respectively. Forty-three implant failures (17.8%) in 17 prostheses (17/76; 22.4%) were observed in this study. The average period of implant failure was 43.3 ± 41.0 months, and most of them were maxillary turned implants. The bar-clip system demonstrated more complications in the attachment parts compared to the ball attachment system. Poor retention of the prosthesis was similar between the two systems. Loss of implants resulted in the failure of 10 ODs in this study. ODs opposed by natural dentition or fixed prostheses presented with more complications. The Cox proportional hazards model did not show a significant effect on prosthesis failure for any of the factors. These findings indicated that patients with ODs need constant maintenance follow-ups to address the technical complications and perform prosthodontic maintenance regardless of the attachment system used.

Complications of Fixed Full-Arch Implant-Supported Metal-Ceramic Prostheses

We aimed to assess the biological and mechanical-technical complications and survival rate of implants of full-arch metal-ceramic prostheses, during five years of follow-up. 558 implants (of three different brands) retaining 80 full-arch metal-ceramic prostheses were placed in 65 patients, all of whom were examined annually for biological and mechanical-technical complications during the five years of follow-up. Descriptive statistics and univariate logistic regression were calculated. The cumulative survival rate of the implants was 99.8%, and 98.8% prosthesis-based. Mucositis was the most frequent of the biological complications and peri-implantitis was recorded as 13.8% at restoration-level, 16.9% at patient level and 2.0% at implant level. An implant length greater than 10 mm was shown to be a protective factor against biological complications. The mechanical-technical complications were associated with implant diameter, abutment/implant connection and retention system. Loss of screw access filling was the most frequent prosthetic complication, followed by the fracture of the porcelain. Full-arch metal-ceramic prostheses show a high prevalence of implant and prosthesis survival, with few biological and mechanical-technical complications.

Number of Implants May Not Significantly Affect Long-term Clinical Outcomes of Complete-Arch Implant-Supported Prosthesis

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Optimal number of implants for complete-arch implant-supported prostheses with a follow-up of at least 5 years: A systematic review and meta-analysis. de Luna Gomes JM, et al. J Prosthet Dent 2019;121(5):766-774.e3.

SOURCE OF FUNDING

Information not available.

TYPE OF STUDY/DESIGN

Systematic review with meta-analysis of data.

Comparison of Four Implant-Supported Fixed Rehabilitation Options of the Edentulous Mandible: A 3D Finite Element Analysis

Aim:

This study aims to compare four implant-supported rehabilitation concepts of an edentulous mandible and determines the most biomechanically advantageous technique.

Materials and Methods:

Five models with four implants in different configurations were formed: four axial interforaminal implants, All-on-4 concept (two anterior axial and two posterior distally tilted implants), All-on-4v4 concept (four distally tilted interforaminal implants), All-on-4W (two anterior mesially tilted and two posterior distally tilted implants), and two axial interforaminal implants and two posterior extra-short implants. Straumann bone-level (4.1 × 12 mm) and tissue-level (4.1 × 4 mm) extra-short implants were used for this study. Spherical loadings from canine and molar regions were applied to evaluate tension, compression, and von Mises stresses by implementing 3D finite element analysis.

Results:

Among the alternative concepts, the classic All-on-4 and the All-on-4v4 techniques were the most successful treatment option in biomechanical terms. On the other hand, the use of extra-short implants in the posterior region was found to be the last method of choice. This was because of the high stresses on bones in most conditions, even though it balances the forces from the molar region on the implants.

Conclusion:

The results of the present study indicate that the classic All-on-4 and the All-on-4v4 techniques were the most successful treatment options in biomechanical terms for the rehabilitation of an edentulous mandible with four implant-supported fixed full-arch prostheses.

Maxillary zirconia and mandibular composite resin-lithium disilicate-modified PEEK fixed implant-supported restorations for a completely edentulous patient with an atrophic maxilla and mandible: A clinical report

Bimaxillary implant-supported restorations for edentulous patients must include a comprehensive diagnosis, treatment plan, and careful selection of the restorative materials. The present clinical report described a completely edentulous patient rehabilitated with a zirconia framework with a facial ceramic veneer on the maxillary arch and a modified polyetheretherketone (PEEK) framework with gingival composite resin and cemented lithium disilicate crowns on the mandibular arch. The rationale for this combination of restorative materials is reviewed.

Are There Alternatives to Invasive Site Development for Dental Implants? Part II

Despite improvements in bone preservation following tooth extraction, edentulous sites are often deficient in bone volume for conventional dental implant therapy. Missing bone volume is often recaptured by surgery and grafting. This article discusses noninvasive alternatives to bone grafting. Part I of this topic discussed the use of short and narrow diameter implants. Part II discusses three additional alternatives: the use of tilted implants, the use of four or fewer tilted and axially-loaded implants to support a full-arch fixed-dental-prosthesis (FAFDP), and the use of zygomatic implants to restore the severely-atrophic edentulous maxillae lacking adequate bone for conventional treatment.

The influence of prosthetic material on implant and prosthetic survival of implant-supported fixed complete dentures: a systematic review and meta-analysis

PURPOSE

Evaluating the impact of the prosthetic material on implant- and prosthetic survival of implant-supported fixed complete dentures.

STUDY SELECTION

Electronic and hand searches were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) to identify clinical studies including at least 10 patients restored with implant-supported dentures. The primary outcome was to evaluate the implant survival rate according to the applied restorative materials. The prosthetic survival rate was evaluated as secondary outcomes.

RESULTS

Forty-one of 2254 studies were finally selected. A statistically significant difference (p = 0.0337) was found between implant survival rates in the main restorative groups (metal-ceramic:97%(95%CI [0.96;0.98]), all-ceramic:99%(95%CI [0.98;1.00]), metal-resin:97%(95%CI [0.96;0.98])). Prosthetic survival rates were: (metal-ceramic:95%(95%CI [0.89;0.97]), all-ceramic:97%(95%CI [0.92;0.99]), metal-resin:97%(95%CI [0.95;0.98]), with no statistically significant difference (p = 0.3796) between the groups. Chipping incidence rates were as follows: metal-ceramic:8%(95%CI[0.03;0.20]), all-ceramic:15%(95%CI [0.06;0.32]), and metal-resin:22%(95%CI [0.13;0.33]). Five types of exact restorative materials were identified (porcelain-fused-to-non-precious alloy, porcelain-fused-to-zirconia, precious-metal-acrylic-resin, non-precious-metal-acrylic resin, and PMMA). Again, implant survival rates were statistically significantly influenced by the applied restorative materials (p = 0.0126), whereas, no significant differences were reported regarding prosthetic survival rate.

CONCLUSIONS

Prosthetic material selection seems to have no clinically relevant influence on implant- and prosthetic survival rate in implant-supported fixed complete dentures. Due to the high chipping rate, quantifying prosthetic survival alone does not seem to be a reliable tool for evaluating the outcome of the restorations and providing recommendations. These results, along with the obvious lack of evidence, suggest that clinicians must exercise caution whenever porcelain-fused-to-zirconia or metal-resin restorations are considered.

Micromotion of implant-abutment interfaces (IAI) after loading: correlation of finite element analysis with in vitro performances

Micromotion between IAI affects long-term survival rate of dental implants. The use of practical implants for mechanical test is costly. Finite element analysis (FEA) could test the micron level deformation changes, but whether it reflects the in vitro mechanical performances remains unknown. This study aims to investigate the correlation between IAI micromotion of FEA and in vitro performances. The two-step-two-component FEA method was used to test the relative deformation between IAI for three implant designs (M1, M2, and M3) during torque loading and cyclic oblique loading. The micromotion was divided into directions that perpendicular to (x-axis) and parallel to (y-axis) IAI. In vitro experiments on the micromotion relevant performance of IAI microleakage (tested by toluidine blue releasing with a spectrometer) and IAI locked condition (tested by abutment removal force tests after detaching the central screws) were also conducted for the identical implant systems (G1, G2, and G3). One-way ANOVA and Pearson's correlation tests were performed for data analysis. FEA illustrated that the three implant systems performed different micromotion patterns. Significant differences were found in the IAI microleakage and removal force among the groups. Positive correlations were found between FEA and in vitro outcomes. Therefore, the two-step-two-component FEA method is an appropriate method to evaluate the IAI micromotion after loading. Graphical abstract The correspondence of IAI micromotion between FEA analysis and in vitro performances.

Combining Intraoral and Face Scans for the Design and Fabrication of Computer-Assisted Design/Computer-Assisted Manufacturing (CAD/CAM) Polyether-Ether-Ketone (PEEK) Implant-Supported Bars for Maxillary Overdentures

PURPOSE

To present a digital method that combines intraoral and face scanning for the computer-assisted design/computer-assisted manufacturing (CAD/CAM) fabrication of implant-supported bars for maxillary overdentures.

METHODS

Over a 2-year period, all patients presenting to a private dental clinic with a removable complete denture in the maxilla, seeking rehabilitation with implants, were considered for inclusion in this study. Inclusion criteria were fully edentulous maxilla, functional problems with the preexisting denture, opposing dentition, and sufficient bone volume to insert four implants. Exclusion criteria were age < 55 years, need for bone augmentation, uncompensated diabetes mellitus, immunocompromised status, radio- and/or chemotherapy, and previous treatment with oral and/or intravenous aminobisphosphonates. All patients were rehabilitated with a maxillary overdenture supported by a CAD/CAM polyether-ether-ketone (PEEK) implant-supported bar. The outcomes of the study were the passive fit/adaptation of the bar, the 1-year implant survival, and the success rates of the implant-supported overdentures.

RESULTS

15 patients (6 males, 9 females; mean age 68.8 ± 4.7 years) received 60 implants and were rehabilitated with a maxillary overdenture supported by a PEEK bar, designed and milled from an intraoral digital impression. The intraoral scans were integrated with face scans, in order to design each bar with all available patient data (soft tissues, prosthesis, implants, and face) in the correct spatial position. When testing the 3D-printed resin bar, 12 bars out of 15 (80%) had a perfect passive adaptation and fit; in contrast, 3 out of 15 (20%) did not have a sufficient passive fit or adaptation. No implants were lost, for a 1-year survival of 100% (60/60 surviving implants). However, some complications (two fixtures with peri-implantitis in the same patient and two repaired overdentures in two different patients) occurred. This determined a 1-year success rate of 80% for the implant-supported overdenture.

CONCLUSIONS

In this study, the combination of intraoral and face scans allowed to successfully restore fully edentulous patients with maxillary overdentures supported by 4 implants and a CAD/CAM PEEK bar. Further studies are needed to confirm these outcomes.

Biomechanical behavior of titanium and zirconia frameworks for implant-supported full-arch fixed dental prosthesis

BACKGROUND

The biomechanical behavior of implant-supported titanium and zirconia full-arch fixed dental prosthesis (FAFDP) frameworks require further investigation.

PURPOSE

Strains transferred by implant-supported titanium (Ti) and zirconia (Zr) FAFDP frameworks were analyzed.

MATERIALS AND METHODS

Maxillary 14-unit FAFDPs supported by 6 implants and 12-unit FAFDPs supported by 4 implants were tested. One-piece frameworks were fabricated by computer-aided design/computer-aided manufacturing. Four groups were divided (n = 3): G1, Ti-6 implants; G2, Zr-6 implants; G3, Ti-4 implants; G4, Zr-4 implants. A 250 N single-point load was applied on the second premolar. A three-dimensional digital image correlation system recorded framework and maxilla model surface deformation.

RESULTS

The following strains (μS) averaged over the length of the second premolar were calculated: frameworks, G1 (321.82 ± 111.29), G2 (638.87 ± 108.64), G3 (377.77 ± 28.64), G4 (434.18 ± 132.21); model surface, G1 (473.99 ± 48.69), G2 (653.93 ± 45.26), G3 (1082.50 ± 71.14), G4 (1218.26 ± 230.37). Zirconia frameworks supported by 6 implants (G2) presented higher surface strains (P < .05). FAFDPs with titanium frameworks transferred significantly lower strains to the supporting maxilla when 6 implants were used (G1) (P < .05). Both framework materials transferred similar strains when supported by 4 implants (G3 and G4) (P > .05).

CONCLUSIONS

Zirconia frameworks supported by 6 implants showed higher strains. FAFDPs supported by 6 implants transferred less strains to the supporting maxilla, irrespective of framework material.

Fixed Full Arches Supported by Tapered Implants with Knife-Edge Thread Design and Nanostructured, Calcium-Incorporated Surface: A Short-Term Prospective Clinical Study

Purpose. To evaluate implant survival, peri-implant bone loss, and complications affecting fixed full-arch (FFA) restorations supported by implants with a knife-edge thread design and nanostructured, calcium-incorporated surface. Methods. Between January 2013 and December 2015, all patients referred for implant-supported FFA restorations were considered for enrollment in this study. All patients received implants with a knife-edge thread design and nanostructured calcium-incorporated surface (Anyridge®, Megagen, South Korea) were restored with FFA restorations and enrolled in a recall program. The final outcomes were implant survival, peri-implant bone loss, biologic/prosthetic complications, and “complication-free” survival of restorations. Results. Twenty-four patients were selected. Overall, 215 implants were inserted (130 maxilla, 85 mandible), 144 in extraction sockets and 71 in healed ridges. Thirty-six FFAs were delivered (21 maxilla, 15 mandible): 27 were immediately loaded and 9 were conventionally loaded. The follow-up ranged from 1 to 3 years. Two fixtures failed, yielding an implant survival rate of 95.9% (patient-based). A few complications were registered, for a “complication-free” survival of restorations of 88.9%. Conclusions. FFA restorations supported by implants with a knife-edge thread design and nanostructured, calcium-incorporated surface are successful in the short term, with high survival and low complication rates; long-term studies are needed to confirm these outcomes.

The all-on-four concept may be a viable treatment option for edentulous rehabilitation

Data sourcesMedline, the Cochrane Library, Google and hand-searches of systematic reviews and bibliographies from related journals in English and German up to August 2012.Study selectionThree reviewers independently searched for clinical trials that assessed the success rates of placing two anterior and two posterior tilted dental implants in humans either in the maxilla or mandible according to the all-on-four treatment concept. Inclusion limited studies with a minimum follow-up period of one year.Data extraction and synthesisThe primary outcome measure was the failure rate of implants. The secondary outcomes were prosthesis failure and marginal bone loss/bone level changes assessed through radiological examination. Failure rate was used to calculate standard deviations (SDs) of implants, whereas the mean success rate was used for dental implants and prostheses. Evaluation and quality assessment of articles and data extraction were performed by three independent reviewers. These reviewers estimated risk of bias by assessing the trial quality using a criteria form focused on the trial design, specification of inclusion/exclusion criteria, performance of surgery, outcome measure provided, radiographic examination of marginal bone level change as well as its evaluation and completeness of follow-up. Outcome measures were based on weighted means using a variance components analysis.ResultsThirteen studies, including 4,804 dental implants (2,000 maxilla and 2,804 mandible) placed in 1,201 jaws met the inclusion criteria. Nine were prospective trials, three retrospective studies and one longitudinal trial. All studies except one were considered to be at high risk of bias. Seventy-four (37 axially, 37 tilted) dental implants failed, with most failures (74%) within the first 12 months. Fifty-seven out of 1,201 prostheses failed but were repairable. The major prosthetic complication was the fracture of the all-acrylic prostheses. At 36 months the mean cumulative survival rates for implants and prostheses were 99.0 ± 1.0% (SD) and 99.9 ± 0.3% (SD), respectively with an average bone loss of 1.3 ± 0.4 mm (SD). There were no statistically significant differences in the clinical outcomes between maxillary versus mandibular arches and axially versus tilted placed implants.ConclusionsThe available evidence shows a promising short-term prognosis for the all-on-four treatment concept. However the evidence is limited by the quality of the available studies and the paucity of clinical trials of greater than five years.

Implant-Supported Immediately Loaded Fixed Full-Arch Dentures: Evaluation of Implant Survival Rates in a Case Cohort of up to 7 Years

BACKGROUND

The treatment of severely atrophied and edentulous jaws by means of fixed implant supported solutions is a challenging procedure.

PURPOSE

The immediate loading of four to six axial and tilted implants offers the possibility to overcome elaborate hard tissue augmentation procedures but lacks implant and patient related data on implant survival rates.

MATERIALS AND METHODS

This retrospective 7-years clinical trial investigated the implant survival rates of 2,081 implants (380 patients, 482 jaws) using an immediate loading protocol with either 4, 5, or 6 implants per restoration. Survival rates were calculated concerning implantation related factors (jaws/number of supporting implants/angulations/diameters/lengths) and patient related factors (medical status/smoking).

RESULTS

Overall survival of 2,081 implants was 97.0% on implant level. Survival rates of implantation related factors did not yield significant differences. Significant differences were yield between healthy patients and patients with osteoporosis (p = .002) and the medical status group "other" (p = .032), respectively. Smokers yielded a significantly higher survival than nonsmokers (p = .002).

CONCLUSIONS

It is assumed that four implants per jaw serve as a sufficient implant number for full arch restorations in both, the mandible and the maxilla. Osteoporosis under the medication with bisphosphonates seems to be a risk factor for implant survival. The authors suggest that the effect of smoking on ISRs remains controversial within this treatment concept.

Four-implant overdenture fully supported by a CAD-CAM titanium bar: A single-cohort prospective 1-year preliminary study

STATEMENT OF PROBLEM

In patients with an altered skeletal maxillomandibular relationship and bone resorption, the rehabilitation of edentulous jaws by combining 4 implants, 2 straight medially and 2 tilted distally, may be preferred to avoid a bone augmentation procedure.

PURPOSE

The purpose of this single cohort 1-year prospective study was to evaluate the clinical performance of a 4-implant overdenture fully supported by a computer-aided designed and computer-aided manufactured (CAD-CAM) titanium bar.

MATERIAL AND METHODS

This single cohort prospective study included edentulous participants rehabilitated with a 4-implant overdenture in 1 of the 2 jaws. The outcomes were implant and prosthetic survival and success rates, any biologic and technical complications, periimplant marginal bone loss, changes in the oral health impact profile (OHIP), bleeding on probing, and the plaque index.

RESULTS

Eighteen participants received 72 implants. One year after implant placement, no implants or prosthesis had failed, and no biologic or technical complications had been observed. At the 1-year follow-up, the mean marginal bone loss was 0.29 ±0.16 mm. The OHIP summary scores demonstrated a significant improvement in oral health-related quality of life. At the 1-year follow-up, positive bleeding was found in 2 participants (11.1%) around 3 implants (4.1%). Three participants (16.6%), accounting for 5 implants (6.9%), showed a slight amount of plaque.

CONCLUSIONS

A 4-implant overdenture supported by a CAD-CAM titanium bar may be a reliable option for the treatment of the edentulous mandible and maxilla over a 1-year period. Oral health-related quality of life significantly improved in all treated participants.

Different sealing materials preventing the microbial leakage into the screw-retained implant restorations: an in vitro analysis by DNA checkerboard hybridization

OBJECTIVES

The aim of this controlled in vitro study was to identify and quantify up to 38 microbial species penetrating through the screw-retained implant prostheses with different sealing materials.

MATERIAL AND METHODS

Sixty morse cone implants were restored with single-unit screw-retained prostheses. All the components were randomly divided into five groups (n = 12) according to the proposed materials: (1) polytetrafluoroethylene tape+composite resin; (2) polytetrafluoroethylene tape+gutta-percha; (3) polytetrafluoroethylene tape+light-polymerized provisional composite; (4) cotton pellet+gutta-percha; and (5) cotton pellet+light-polymerized provisional composite. Human saliva was used as contaminant media, and DNA checkerboard hybridization was used to identify and quantify microbial species.

RESULTS

Microbial leakage was observed in all groups: M. salivarium, S. pasteuri, P. nigrescens, and P. melaninogenica were the species presenting the highest values of genome count, prevalence, and proportion within the groups. The total microbial mean counts (×10⁵ , ±SD) were as follows: Group 1 (2.81 ± 0.38), Group 2 (3.41 ± 0.38), Group 3 (6.02 ± 1.48), Group 4 (6.40 ± 1.42), and Group 5 (17.45 ± 1.67). Group 5 showed the higher microbial counts (P < 0.001).

CONCLUSIONS

Moderate to high counts of pathogenic/nonpathogenic species were detected in the inner parts of implants from all groups. The lowest values of microbial counts were recorded for polytetrafluoroethylene tape associated with composite resin or gutta-percha; cotton pellet associated with light-polymerized provisional composite presented the highest microbial counts.

Influence of Cyclic Fatigue in Water on Screw Torque Loss of Long-Span One-Piece Implant-Supported Zirconia Frameworks

PURPOSE

It is still unclear whether four, six, or more implants should be used when restoring fully edentulous maxillae. This research evaluated the in vitro screw torque loss of zirconia frameworks supported by six implants and cantilevered zirconia frameworks supported by four implants.

MATERIALS AND METHODS

Computer aided design/computer-assisted machining was used to fabricate 10 one-piece frameworks. Standardized pressable porcelain crowns were fabricated and luted to the frameworks. Specimens were divided into two groups (n = 5): AO4, cantilevered 12-unit full-arch fixed dental prosthesis supported by four implants; AO6, 14-unit supported by six implants. An opposing mandibular dental arch was fabricated with bis-acrylic composite resin. Specimens were submitted to 200 N underwater cyclic load at 2-Hz frequency for 1 × 10⁶ cycles in a controlled 37°C temperature. A digital torque gauge assessed the initial and postload screw removal torque. Linear mixed-effects model was used for statistical analysis (α = 0.05).

RESULTS

Significant screw torque loss was found for AO6 after cyclic loading (before: 36.20%/after: 52.82%; p < 0.05). Group AO6 (36.20%) presented lower preload loss before the cyclic loadings compared with AO4 (60.10%) (p < 0.05).

CONCLUSIONS

Cyclic loading and lower implant-to-replaced-units ratio do not seem to compromise screw stability compared with higher implant-to-replaced-units ratio; however, a steep drop in preload was found before cyclic loading for both groups.

Five-Year Results of a Randomized Controlled Trial Comparing Patients Rehabilitated with Immediately Loaded Maxillary Cross-Arch Fixed Dental Prosthesis Supported by Four or Six Implants Placed Using Guided Surgery

PURPOSE

To compare the 5-year clinical and radiological outcomes of patients rehabilitated with four or six implants placed using guided surgery and immediate function concept.

MATERIALS AND METHODS

Forty patients randomly received four (All-on-4) or six (All-on-6) immediately loaded implants, placed using guided surgery, to support a cross-arch fixed dental prosthesis. Outcome measures were survival rates of implants and prostheses, complications, peri-implant marginal bone loss, and periodontal parameters.

RESULTS

No drop-out occurred. Seven implants failed at the 5-year follow-up examination: six in the All-on-6 group (5%) and one in the All-on-4 group (1.25%), with no statistically significant differences (p = .246). No prosthetic failure occurred. Both group experienced some technical and biologic complications with no statistically significant differences between groups (p = .501). All-on-4 treatment concept demonstrated a trend of more complications during the entire follow-up period. A trend of more implant failure was experienced for the All-on-6 treatment concept. Marginal bone loss (MBL) from baseline to the 5-year follow-up was not statistically different between All-on-4 (1.71 ± 0.42 mm) and All-on-6 (1.51 ± 0.36 mm) groups (p = .12). For periodontal parameters, there were no differences between groups (p > .05).

CONCLUSION

Both approaches may represent a predictable treatment option for the rehabilitation of complete edentulous patients in the medium term. Longer randomized controlled studies are needed to confirm these results.

Mucosal Manifestations in the Edentulous Maxilla with Implant Supported Prostheses: Clinical Results from a Well-Maintained Patient Cohort

BACKGROUND

Prostheses in the edentulous maxilla affect the mucosa.

PURPOSE

To evaluate mucosal alterations with implant supported fixed prostheses (FDP) and overdentures (IOD).

MATERIAL AND METHODS

Patients receiving prostheses during a time period of 10 years were recruited. Maxillary mucosal conditions in relation to FDPs, IODs were analyzed. Peri-implant parameters were measured and the Oral Health Impact Profile (OHIP) was administered.

RESULTS

One hundred seven patients wearing 74 IODs and 33 FDPs were identified with a total of 519 implants, the mean observation time was 6.5 ± 2.7. Cumulative implant survival was 93%. Erythema and hyperplastic tissue were identified in 71% of the IOD wearers, but were mostly absent with FDPs. The peri-implant parameters demonstrated healthy peri-implant mucosa. Medication and smoking had no effect on mucosal alteration (OR = 1.065 and 1.568). The average OHIP value was 3.73 ± 4.12. A lower value (p < 0.0048) was found for FDPs and one type of IOD.

CONCLUSIONS

A rigorous maintenance program did not prevent IOD mucosal alterations in IOD wearers, but the health of the peri-implant mucosa was maintained and was comparable for all types of prostheses.

A systematic review and meta-analysis of removable and fixed implant-supported prostheses in edentulous jaws: post-loading implant loss

Objectives

The aim of this systematic review was to analyze post‐loading implant loss for implant‐supported prostheses in edentulous jaws, regarding a potential impact of implant location (maxilla vs. mandible), implant number per patient, type of prosthesis (removable vs. fixed), and type of attachment system (screw‐retained, ball vs. bar vs. telescopic crown).

Material and methods

A systematic literature search for randomized‐controlled trials (RCTs) or prospective studies was conducted within PubMed, Cochrane Library, and Embase. Quality assessment of the included studies was carried out, and the review was structured according to PRISMA. Implant loss and corresponding 3‐ and 5‐year survival rates were estimated by means of a Poisson regression model with total exposure time as offset.

Results

After title, abstract, and full‐text screening, 54 studies were included for qualitative analyses. Estimated 5‐year survival rates of implants were 97.9% [95% CI 97.4; 98.4] in the maxilla and 98.9% [95% CI 98.7; 99.1] in the mandible. Corresponding implant loss rates per 100 implant years were significantly higher in the maxilla (0.42 [95% CI 0.33; 0.53] vs. 0.22 [95% CI 0.17; 0.27]; P = 0.0001). Implant loss rates for fixed restorations were significantly lower compared to removable restorations (0.23 [95% CI 0.18; 0.29] vs. 0.35 [95% CI 0.28; 0.44]; P = 0.0148). Four implants and a fixed restoration in the mandible resulted in significantly higher implant loss rates compared to five or more implants with a fixed restoration. The analysis of one implant and a mandibular overdenture also revealed higher implant loss rates than an overdenture on two implants. The same (lower implant number = higher implant loss rate) applied when comparing 2 vs. 4 implants and a mandibular overdenture. Implant loss rates for maxillary overdentures on <4 implants were significantly higher than for four implants (7.22 [95% CI 5.41; 9.64] vs. 2.31 [1.56; 3.42]; P < 0.0001).

Conclusions

Implant location, type of restoration, and implant number do have an influence on the estimated implant loss rate. Consistent reporting of clinical studies is necessary and high‐quality studies are needed to confirm the present results.

Photoelastic stress analysis of mandibular fixed prostheses supported by 3 dental implants

PURPOSE

To observe the photoelastic stress patterns generated around implants in relation to variations in the diameter and total number of implants supporting fixed complete-arch mandibular frameworks.

MATERIALS AND METHODS

Three different implant configurations were analyzed (n = 3): 5 standard implants with diameters of 3.75 mm (C), 3 standard implants with diameters of 3.75 mm (3S), and 3 wide implants with diameters of 5.0 mm (3W). The samples were subjected to a vertical compressive load (1.33 kgf) applied at the end of the distal cantilever of the framework. The shear stresses were calculated around the implants, and the data were analyzed using one-way analysis of variance.

RESULTS

The implants nearest to the loading showed higher stress values regardless of the group. The C group showed lower shear stress when compared with the other groups (P = 0.001). No significant difference was observed between the 3W and 3S groups (P = 0.785).

CONCLUSION

A reduction in the number of implants, regardless of the implant diameter, showed higher stress concentration around the implants. Five-implant configuration showed lower stress concentration and seems to be more biomechanically predictable.

Systematic review of short- (5-10 years) and long-term (10 years or more) survival and success of full-arch fixed dental hybrid prostheses and supporting implants

OBJECTIVES

The aim of this systematic review was to investigate the short-term (5-10 year mean follow-up) and long-term (10 year or more) survival and success of fixed full arch dental hybrid prosthesis and supporting dental implants.

METHODS

Studies reporting interventions with full-arch fixed dental hybrid prostheses were identified by searching PubMed/Medline (NCBI), Web of Science (Thomson Reuters), the Cochrane Register of Controlled Clinical Trials (EBSCO), and Dentistry and Oral Sciences Source (DOSS; EBSCO) from the earliest available dates through July 17, 2013. Through a series of review process by two examiners, potentially qualifying studies were identified and assessed with respect to the inclusion criteria.

RESULTS

A total of 18 studies were included for the quality assessment and the systematic review. Within the limitation of available studies, high short-term survival rates of full arch fixed dental hybrid prostheses (93.3-100%) and supporting implants (87.89-100%) were found. However, the availability of studies investigating long-term outcomes seemed scarce. Furthermore, the included studies were subjected to potential sources of bias (i.e. publication, reporting, attrition bias).

CONCLUSIONS

Despite seemingly high short-term survival, long-term survival of implant supported full arch fixed dental hybrid prosthesis could not be determined due to limited availability of true long-term studies. Although it may be a valuable option for a patient with a completely edentulous ridge(s), the strategic removal of teeth with satisfactory prognosis for the sake of delivering an implant supported full-arch dental hybrid prosthesis should be avoided.