An In Vitro Evaluation of Periotest Implant Stability Measurements Taken on Implant Retained Crowns and Healing Abutments.

OBJECTIVE: To assess the reliability of implant stability measurements recorded with the Periotest device and to investigate the differences in values when these measurements were taken on implant retained crowns and healing abutments. MATERIALS AND METHODS: Fifty-six implants in eight synthetic bone blocks were used to carry out implant stability measurements using the Periotest device by two different operators. Each block constituted an example of bone of density D1, D2, D3, or D4, and two blocks of each density were used. The healing abutments placed were of a height to allow approximately 6 mm of the implant-abutment complex to be supracrestal and temporary crowns were made to match the dimensions of an average central incisor. Descriptive statistics were used to describe the perio test values (PTVs) at each of the different heights on the implant abutments and implant crowns. Means for each site were calculated and distribution of data assessed using the Kruskal Wallis test. The interclass correlation coefficient (ICC) was used to determine the relationship between the PTVs recorded on the implant abutments and implant crowns. RESULTS: The mean PTV (±standard devidation) recorded across all sites was 5.57 ± 11.643 on the implant abutments, and 12.27 ± 11.735 on the temporary crowns. Excellent/good inter-operator ICCs were recorded for the mid-abutment site in all bone blocks D1-D4 (ICC = 0.814, p < 0.001, ICC = 0.922, p < 0.001, ICC = 0.938, p < 0.001, ICC = 776, p < 0.001). For mid crown sites, ICC between operators was excellent/good only for recordings in D2 bone (ICC = 0.897, p < 0.001). CONCLUSIONS: Periotest device seems to be able to reliably measure implant stability across all types of bones when the implant stability is assessed at approximately 3 mm coronal to the implant platform for abutments and 4.5 mm for implant supported single crowns.

Does the Use of Surface Electromyography Could Improve Quality of Life among Patients Rehabilitated by Mandibular Overdentures on Different Attachments?

Abstract Objective: To analyze and compare changes of quality of life parameter among dental patients rehabilitated by the implant-supported overdentures with different attachment systems. Material and Methods: Forty-eight patients were recruited as a study cohort. The implant placement procedure was based on the results obtained by CBCT scanning and individualized surgical templates manufactured for correct implant placement. Each individual received two k3Pro Implants (Sure Type with 4.0 or 4.5 mm in diameter) at the intraforaminal area due to standard protocol of implantation provided by the manufacturer under local anesthesia. All patients were distributed between two groups based on the fact of using either Locator- or ball-attachments. Rank correlation was measured using Spearman correlation coefficient, while linear correlation was evaluated by Pearson correlation coefficient. Results: No statistically meaningful differences were noted regarding patients' distribution among groups considering age (p>0.05) and gender (p>0.05). Provided patient-level analysis demonstrated that increase of conventional full denture service time was positively correlated with escalation of OHIP-EDENT scores. The most prominent inter-correspondences were noted specifically between longevity of denture service and elevation of scores within "Functional limitation" (r=0.61; p<0.05), "Physical pain" (r=0.51; p<0.05) and "Physical disability" (r=0.57; p<0.05) subdomains. No statistically argumented regressions were noted between increase tendency of OHIP-EDENT scores and gender (p>0.05) or age (p>0.05) parameters. Conclusion: Significant improvements of quality of life measured with OHIP-EDENT were noted for both types of attachments compared to the pre-treatment situation independently of additionally provided surface electromyography-based alignment.

Long-Term Effectiveness of Extra-Short (≤ 6 mm) Dental Implants: A Systematic Review

PURPOSE: This systematic review evaluated the mean survival rate and marginal bone loss (MBL) of dental implants with ≤ 6 mm in length, across a time frame of 5 years. The overall prosthetic and biologic complications were evaluated, and their survival rates obtained. In addition, the complication rates of the splinted vs nonsplinted implants were assessed. MATERIALS AND METHODS: An electronic literature search in PubMed (MEDLINE) and EMBASE (OVID) and Cochrane were performed, in addition to a manual search through all periodontics and implantology-related journals, up to October 2017, to identify relevant articles. RESULTS: Out of 515 potentially eligible articles, 19 investigations assessing a total of 910 extra-short (≤ 6 mm) implants were included and further evaluated. After 5 years of follow-up, a mean survival rate of 94.1% (90% in the maxilla and 96% in the mandible) and a maximum bone loss of 0.53 mm were demonstrated. Additionally, a statistically significant difference in terms of bone loss was observed between tissue-level (0.12 mm) and bone-level implants (0.36 mm) at 12 months (P < .01), but not between internal and external abutment connections (P = .17). The most commonly reported prosthetic complication was screw loosening. Finally, splinted implants showed less overall prosthetic complications (RR = 3.32; 95% CI: 1.9 to 5.7), screw loosening (RR = 15.2; 95% CI: 5.92 to 39.31), and implant failure (RR = 1.96; 95% CI: 0.8 to 4.8) than nonsplinted implants. CONCLUSION: Extra-short implants are a viable treatment alternative in ridges exhibiting atrophy, demonstrating a satisfactory survival rate, as well as a low rate of prosthetic and biologic complications across a 5-year follow-up. Additionally, splinting extra-short implants is associated with fewer prosthetic complications and lower implant failure rate compared with nonsplinted implants.

Fabrication of a Simple Acrylic Template to Standardize Periapical Radiographs for Implants Retaining Mandibular Bar Overdentures.

A standardized periapical radiograph is still the most suitable technique for monitoring peri-implant osseous destruction during long-term treatment. This article describes a new method for custom fabrication of an acrylic template with standardized reproducible assessment of implants retaining mandibular bar overdentures, without removal of the bar and regardless of the implant system used.

Locator Versus Bar Attachment Effect on the Retention and Stability of Implant-Retained Maxillary Overdenture: An In Vitro Study.

PURPOSE: To compare retention and stability of Locator and bar attachments for implant-retained maxillary overdentures. MATERIALS AND METHODS: Four implants were inserted into a maxillary acrylic resin model in canines and second premolar areas. Experimental overdentures were connected to the implants with bar (group I) or Locator (group II) attachments. Locators were divided into 3 subgroups according the degree of retention of the patrix nylon insert: Locator blue (group IIa), Locator pink (group IIb), and Locator transparent (group IIc). Retention (vertical dislodging) and stability (lateral, anterior, posterior dislodging) forces (N) were measured at the start of the experiment (initial retention) and after 540 cycles of denture insertion and removal (final retention). RESULTS: The highest initial and final stability was recorded with group IIc, followed by group IIb and group IIa, and the lowest retention and stability was noted with group I. For all groups, the highest final retention and stability forces were noted with vertical dislodging, followed by posterior dislodging, anterior dislodging, and lateral dislodging. The highest loss of retention and stability was recorded with group I, followed by group IIc, group IIb, and group IIa. CONCLUSION: Locator attachments are recommended to retain maxillary overdentures over Dolder bar attachments, as Locator attachments were associated with high retention and stability after wear simulation with minimal retention loss.

Clinical Effectiveness of 6.5-mm-Long Implants to Support Two-Implant Fixed Prostheses in Premolar-Molar Region: The Influence of Immediate Loading and the Length of Splinting Implant.

PURPOSE: The purpose of this retrospective clinical study was to assess the influence of immediate loading and lengths of splinted implants on the clinical effectiveness of 6.5-mm-long implants supporting two-implant fixed prostheses in the premolar-molar regions. MATERIALS AND METHODS: A clinical database was reviewed in a private dental center to select those patients who had 6.5-mm-long implants placed to support two-implant fixed partial prostheses in the premolar-molar regions of the maxilla and the mandible. All implants were immediately loaded. The study groups were defined according to the lengths of the implants. Two groups were identified: the short-short splinted group, when both implants had 6.5 mm lengths, and the short-long splinted group, when one implant was longer than 6.5 mm. A total of 48 dental implants were placed in 16 patients to support 24 two-implant fixed prostheses. The mean follow-up time was 14 ± 5 months. The short-short splinted group included 8 patients with 16 implants; the short-long splinted group included 16 patients with 32 implants. The main variable was implant survival, and secondary outcomes were marginal bone stability and prosthesis survival. RESULTS: The statistical analyses indicated an absence of significant differences between the two groups in terms of implant and prosthesis survival (100% for both groups and both variables); however, distal bone loss around the splinted implants was significantly higher in the short-long splinted group. Bone loss was 0.37 ± 0.55 mm in the short-short splinted group and 0.94 ± 0.66 mm in the short-long splinted group. CONCLUSIONS: Immediate loading of short (6.5-mm-long) implants in the premolar-molar regions did not jeopardize their survival. Two-implant supported prostheses had the same clinical effectiveness, whether extra-short implants were splinted to another extra-short implant or to a longer one.

Effect of Implant Connection Type and Depth on the Seating Accuracy of Hand-Tightened Abutments.

PURPOSE: Improper seating of abutment on the implant is a common problem. This study investigated the effect of the type of implant/abutment interface on the complete seating of the abutments on the head of implants placed at different gingival depths. MATERIALS AND METHODS: Three implant systems with three different connections including straight external hexagon, butt-joint internal tri-lobed, and conical internal hexagon were used. Two gingival thicknesses (2 and 7 mm) were created using pink baseplate wax around the straight abutments seated on the implants. After placing the implants in acrylic blocks, the wax was replaced with the gingival mask material to simulate the gingival drape around the implant heads. Afterwards, 15 prosthodontists were asked to hand-tighten the straight abutments in the corresponding implant bodies relying only on their tactile sense. At the final stage, the gingival mask was removed, and the seating quality of the abutments on implant bodies was assessed visually. The effect of implant connection and depth on abutment seating accuracy was analyzed using Kruskal-Wallis and multiple-comparison tests. RESULTS: No significant difference was found regarding the effect of either depth or connection design on the accuracy of the abutment seating (p > 0.05); however, pairwise comparison of the combined effect of the depth and connection design was significant (p = 0.009). Accuracy of abutment seating on the Nobel Active implants at both 2 and 7 mm depths were significantly better than Replace system with 7 mm depth (p = 0.027). The same results were obtained in comparison between Nobel Active system at both 2 and 7 mm depths with Branemark system with 7 mm depth (p = 0.006). CONCLUSION: An increase in implant placement depth meant a decrease in accuracy of the abutment seating. The internal conical connection design showed the best result in abutment positioning in deep implants as compared with external and internal butt-joint connection designs.

A Novel Extended Range Attachment System to Retain Implant Overdentures: A Clinical Report.

Various attachment systems have been used to facilitate the retention, stability, and support of overdentures. The low profile design, pivoting technology, and durability of the Locator attachment made it one of the commonly used tissue-supported implant-retained overdentures. It has been successfully used to retain overdentures as well as partial dentures. This article describes the uses of the new Locator R-Tx abutment and illustrates both the direct and indirect techniques used to process the denture attachment housing into the prosthesis to retain overdentures and partial dentures.

Accuracy of Different Implant Impression Techniques: Evaluation of New Tray Design Concept.

PURPOSE: To evaluate implant impression accuracy with a new tray design concept in comparison to nonsplinted and splinted impression techniques for a 2-implant situation. MATERIALS AND METHODS: A reference bar titanium framework was fabricated to fit on 2 parallel implants. The framework was used to generate a resin master model with 2 implants that fit precisely against the framework. Three impression techniques were evaluated: (1) nonsplinted, (2) splinted, and (3) nonsplinted with modified tray impressions. All the trays were fabricated from light-cured acrylic resin material with openings that corresponded to the implant impression copings. Ten impressions were taken for each technique using poly(vinyl siloxane) impression material. The impressions were poured with type IV dental stone to generate the test casts. A rosette strain gauge was bonded to the middle of the framework. As the framework retaining screws were tightened on each test cast, the developed strains were recorded until the completion of the tightening to 35 Ncm. The generated strains of the rosette strain gauge were used to calculate the maximum principal strain. RESULTS: A statistically significant difference was observed among the different impression techniques. The modified tray design impression technique was associated with the least framework strains, which indicates greater accuracy compared with the other techniques. There was no significant difference between the splinted and the nonsplinted impression techniques. CONCLUSIONS: The new tray design concept appeared to produce more accurate implant impressions than the other techniques. Despite the statistical difference among the impression techniques, the clinical significance of this difference is yet to be determined.

Retention force and deformation of an innovative attachment model for mini-implant-retained overdentures.

STATEMENT OF PROBLEM: The gradual loss of retention and the need for periodic replacement of attachment-system components are the most frequent complications in implant-supported overdentures. PURPOSE: The purpose of this in vitro study was to develop a new attachment system for overdentures with polymeric materials and compare its retention and deformation with a conventional O-ring attachment system. MATERIAL AND METHODS: A matrix with 2 mini-implants with ball abutments was used to simulate the mandibular border during a fatigue resistance test. A total of 60 polyacetal (n=20), polytetrafluoroethylene (n=20), and conventional O-ring (n=20) attachments were captured in pairs with acrylic resin and subjected to 3625 insertion and removal cycles, simulating 30 months of overdenture use. The internal and external deformations of the attachments were assessed using an optical stereomicroscope. One-way ANOVA and the Tukey honestly significant difference tests were used for statistical evaluation (α=.05). RESULTS: The polyacetal attachment system showed the highest retention (P<.001), followed by the O-ring and polytetrafluoroethylene attachments. The O-ring attachments exhibited the lowest deformation (P<.001), and the polyacetal attachments had the highest internal deformation (P<.001). CONCLUSIONS: The newly developed polyacetal attachment model increased the retention of mini-implant-retained overdentures, and despite the deformation experienced, the retention period appears to be better than that of conventional systems.

Short-term report of an ongoing prospective cohort study evaluating the outcome of full-arch implant-supported fixed hybrid polyetheretherketone-acrylic resin prostheses and the All-on-Four concept.

BACKGROUND: More research is needed on the study of new materials for fixed prosthetic implant-supported rehabilitations. PURPOSE: The purpose of this study was to report the short-term outcome of full-arch implant-supported fixed hybrid polyetheretherketone (PEEK)-acrylic resin prostheses and the all-on-four concept. MATERIALS AND METHODS: This prospective cohort clinical study included 37 patients (29 women, eight men) with an average age of 60 years (range: 38-78 years) with 49 full-arch hybrid PEEK-acrylic resin prosthesis supported by implants through the all-on-four concept. Primary outcome measures were prosthetic survival. RESULTS: Two patients with two maxillary prostheses were lost to follow-up. One patient with a double full-arch rehabilitation fractured the mandibular PEEK framework, rendering a 98% prosthetic survival rate. No implants were lost. The average (SD) marginal bone remodeling after 1 year of follow-up was 0.37 mm (0.58 mm). Technical complications concerning the veneer adhesion occurred in six patients and were resolved in all patients (with exception of the patient with prosthetic failure) through the creation of mechanical retentions and changing the bonding primer. Mechanical complications occurred in three patients and five prostheses consisting in prosthetic screw loosening (n = 2 patients) and fracture of the acrylic resin teeth (the patient with a prosthetic failure). CONCLUSIONS: Within the limitations of this study, the results suggest that hybrid polymer (PEEK)-acrylic resin prostheses supported by implants for full-arch rehabilitation may represent a valid treatment option, still requiring longer-term validation.

Do short implants have similar survival rates compared to standard implants in posterior single crown?: A systematic review and meta-analysis.

BACKGROUND: Short implants have been presented as an option for posterior rehabilitation in cases of poor bone height. PURPOSE: To compare the survival rate of short implants and standard implants when used in posterior single crowns, in addition to reporting marginal bone loss, prosthetic failures, and surgical complications. MATERIALS AND METHODS: Electronic search (PubMed, LILACS, Cochrane Library, Scopus, and Web of Science) and hand search were performed to identify all randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that evaluated both short and standard implants in posterior single crowns. RESULTS: Out of 345 articles identified by both electronic and hand search, four studies were selected (one CCT and three RCTs). The meta-analysis for the survival rate showed that there was no significant difference between the short implants and the standard ones (P = 1.00; RR:1.00; CI:0.97-1.03) performed with three RCTs for a one-year follow-up. The mean marginal bone loss ranged from 0.1 mm to 0.54 mm. Only one study reported the presence of prosthetic failures and surgical complications. CONCLUSIONS: The survival rate of short implants was similar to the standard ones in posterior single crowns, for the one-year follow-up period. They also presented low surgical complications, prosthetic failures and marginal bone loss, being a predictable treatment for single rehabilitation in posterior tooth loss.

Retention and Stability of Rigid Telescopic and Milled Bar Attachments for Implant-Supported Maxillary Overdentures: An In Vitro Study.

PURPOSE: This study aimed to evaluate and compare the retention and stability of rigid telescopic and milled bar attachments for implant-supported maxillary overdentures. MATERIALS AND METHODS: An acrylic resin model of the edentulous maxilla without alveolar undercuts was fabricated, and four implants were inserted in the canine and second premolar areas of the model. Two experimental overdentures were constructed and connected to the model with either rigid telescopic (RTA) or milled bar (MBA) attachments. Resistance of overdentures to axial and nonaxial (anterior, posterior, and lateral) dislodging forces was measured to represent retention and stability, respectively. Measurements were made at the beginning of the study (initial retention) and after 540 cycles of denture insertion and removal (retention after wear simulation). RESULTS: After wear simulation, MBAs recorded significantly higher retention (P < .001) and stability against anterior dislodging (P < .001) than RTAs. RTAs recorded significantly higher stability against posterior (P = .022) and lateral (P < .001) dislodging than MBAs. Initial stability of RTA against anterior (P < .001) and posterior (P < .001) dislodging was significantly higher than stability after wear simulation. Retention of RTAs (P = .020) and stability of MBAs against posterior (P = .038) and lateral (P = .020) dislodging after wear simulation were significantly higher than initial values. CONCLUSION: MBA was associated with increased retention of maxillary implant overdentures compared with RTA, while RTA was associated with increased stability compared with MBA.

The In Vitro comparison of the retention of an implant-supported stud attachment locator and straumann ball attachment at different angulations.

AIM: In this study, we investigated the retention of two attachment types, Straumann ball (SB) and Straumann Locator® (SL) attachments, on different implant angulations and identified the most appropriate treatment type or attachment system for each angulation. MATERIALS AND METHODS: The attachments placed on angulation of 0°-, 10°-, and 20° implants were subjected to 1440 vertical insertion-separation cycles. The retention values of the attachments after 0, 720, and 1440 cycles were measured using the Instron machine. In addition, scanning electron microscopy images of the attachments and abutments were obtained before and after the insertion-separation process. RESULTS: There was a significant difference between the SB and SL attachments that were placed on 0° after 1440 cycles (P < 0.05) and between 20° SB and 20° SL attachments after 720 and 1440 cycles (P < 0.05) in terms of retention. No significant difference was observed between 20° SB and 20° SL attachments at 0 cycles (P > 0.05). CONCLUSIONS: In implants with a 20° angle, retention of stud attachments decreased more than ball attachments after use. Thus, the total angle between the implants should not be <20° if long-term retention is desired when using stud attachments. For implants with angles >20°, 6-month patient controls are required to control retention of attachments by considering factors in the mouth with the two tested attachment systems.

Intraoral scan bodies in implant dentistry: A systematic review.

STATEMENT OF PROBLEM: Intraoral scan body (ISB) design is highly variable and its role in the digital workflow and accuracy of digital scans is not well understood. PURPOSE: The purpose of this systematic review was to determine the relevant reports pertaining to ISBs with regard to design and accuracy and to describe their evolution and role in the digital dentistry workflow. Special attention was placed on their key features in relation to intraoral scanning technology and the digitization process. MATERIALS AND METHODS: A MEDLINE/PubMed search was performed to identify relevant reports pertaining to ISB usage in dentistry. This search included but was not limited to scan body features and design, scan body accuracy, and scan body techniques and the role of ISBs in computer-aided design and computer-aided manufacturing (CAD-CAM) processes. Commercially available scan bodies were examined, and a patient situation was shown highlighting the use of ISBs in the digital workflow. RESULTS: Deficiencies in the reports were found regarding various scan body topics, including ISB features/design, accuracy, and the role of ISBs in CAD-CAM processes. CONCLUSIONS: ISBs are complex implant-positioning-transfer devices that play an essential role in the digital workflow and fabrication of accurately fitting implant-supported restorations. With scanner technology rapidly evolving and becoming more widespread, future studies are needed and should be directed toward all parts of the digital workflow when using ISBs. By understanding the basic components of ISBs and how they relate to digital scanning and CAD-CAM technology, more emphasis may be placed on their importance and usage in the digital workflow to ensure accurate transfer of implant position to the virtual and analog definitive cast. Efforts should be made by clinicians to identify an optimal ISB design in relation to the specific intraoral scanning technology being used.

Polyetheretherketone Overlay Prosthesis over High Noble Ball Attachments to Overcome Base Metal Sensitivity: A Clinical Report.

A modified polyetheretherketone (PEEK) framework material in combination with heat-polymerized denture base acrylic resin was used for the fabrication of an overlay prosthesis for a patient sensitive to base metals. High noble metal was used for the fabrication of the post/coping/ball attachment assemblies to promote retention and stability. These protruding attachments into the acrylic resin could result in stress concentration; therefore, a framework is often used to strengthen the prosthesis. PEEK frameworks could be a treatment alternative to high noble or Ti frameworks since they combine good mechanical properties with biocompatibility, reduced cost, and common laboratory procedures.

Mini-implants and narrow diameter implants as mandibular overdenture retainers: A systematic review and meta-analysis of clinical and radiographic outcomes.

This study reviews the clinical and radiographic outcomes of Mini-implants (MI) and Narrow Diameter Implants (NDI) as mandibular overdenture (MO) retainers. Six databases were consulted for clinical studies that evaluated implants with diameter ≤3.5 mm. Data on the MI and NDI for survival and success rate and peri-implant bone loss and were collected and submitted to meta-analysis. Thirty-six studies were included, 24 reporting MI performance and 12 describing NDI results. The MI group comprised data from 1 cross-sectional clinical study, 3 retrospective longitudinal (RL) clinical studies, 13 prospective longitudinal (PL) clinical studies and 7 randomised clinical trials (RCT) with follow-up periods ranging from 1 day to 7 years. Eight studies used conventional loading, thirteen used immediate loading, two studies used both loading types, and one study did not report. The NDI group comprised data from 3 RL clinical studies, 6 PL clinical studies and 3 RCT with follow-up ranging from 6 months to 10 years. Ten studies used conventional loading, 1 study used immediate loading, and 1 study did not report. The average survival rates of MI and NDI studies were 98% and 98%, respectively, while the average success rates were 93% and 96%, respectively. The average peri-implant bone loss after 12, 24 and 36 months was 0.89, 1.18 and 1.02 mm for MI and 0.18, 0.12 and -0.32 mm for NDI. Both MI and NDI showed adequate clinical behaviour as overdenture retainers. The NDI showed a better long-term predictability to retain OM with most studies adopting conventional loading.

Retentive Properties of O-Ring and Locator Attachments for Implant-Retained Maxillary Overdentures: An In Vitro Study.

PURPOSE: To evaluate and compare retentive properties of O-ring and Locator attachments for implant-retained maxillary overdentures. MATERIALS AND METHODS: Four implant analogs were inserted in canine and second premolar areas of an acrylic edentulous maxillary model. A metal-reinforced experimental acrylic overdenture was constructed and connected to the analogs using either O-ring (group I) or Locator (group II) attachments. Locators were divided into 3 subgroups according the degree of retention of the patrix nylon insert: Locator extra-light retention (group IIa), Locator light retention (group IIb), and Locator medium retention (group IIc). Vertical and oblique (lateral, anterior, and posterior) dislodging forces were measured at the beginning of the study (initial retention) and after 540 cycles of denture insertion and removal (final retention). RESULTS: For vertical, lateral, and anterior dislodging, group IIc recorded the highest initial and final retention, and group I recorded the lowest retention. For posterior dislodging, group I recorded the highest retention, and group IIa recorded the lowest retention. For group II, vertical dislodging recorded the highest initial and final retention, and lateral dislodging recorded the lowest retention. For group I, posterior dislodging recorded the highest initial and final retention, and lateral dislodging recorded the lowest retention. For all dislodging forces (except posterior dislodging), the highest retention loss was recorded in group I, and the lowest retention loss was recorded in group IIa. CONCLUSION: Locator medium attachment was associated with favorable retention during axial (vertical) and nonaxial (anterior and lateral) dislodging compared to other types of Locator inserts and O-ring attachments after a simulated 6-month period of overdenture use.