Clinical performance of conical and electroplated telescopic double crown-retained partial dentures: a randomized clinical study

PURPOSE

The aim of this study was to quantify and compare the clinical performance of cast conical double crown-retained removable partial dentures (C-RPDs) and electroplated double crown-retained removable partial dentures (EP-RPDs).

MATERIALS AND METHODS

A total of 60 RPDs were placed in 54 patients. Participants were randomly assigned to two study groups (C-RPD and EP-RPD). Altogether, 217 abutment teeth were provided with double crowns. Patients were reexamined after 6, 12, 24, and 36 months. The main endpoints were the survival times of RPDs and abutment teeth; secondary endpoints included failure of the facing, loss of cementation of primary crowns, and postprosthetic endodontic treatment. Chi-square tests were used to evaluate group differences regarding characteristics of patients and RPDs. Survival differences were investigated using the log-rank test and Cox regression; secondary endpoints were assessed using logistic regression.

RESULTS

After 36 months, survival was 100% for C-RPDs and 93.3% for EP-RPDs. Cumulative survival for abutment teeth was 97.3% (C-RPDs) and 96.2% (EP-RPDs). Survival differences between the two study groups did not reach statistical significance. The survival of abutments depended on tooth vitality and position; for example, the hazard of tooth loss was 676% higher for nonvital teeth. No differences were found between study groups regarding facing failure, decementation of primary crowns, or postprosthetic endodontic treatment.

CONCLUSIONS

Vitality and position are important to the survival of teeth supporting partial dentures. Longer follow-up and larger patient collectives are needed to evaluate possible differences between cast conical and electroplated telescopic double crown-retained partial dentures.

Strain development of screw-retained implant-supported fixed restorations: procera implant bridge versus conventionally cast restorations

The aim of this study was to quantify the strain development of screw-retained three-unit implant-supported Procera Implant Bridge restorations. Two groups of screw-retained implant-supported restorations (n = 10) were fabricated by means of casting or computer-aided design/computer-assisted manufacture (CAD/CAM) to fit an in vitro cast situation with two implants. During fixation of the restorations, the emerging strains were recorded using strain gauges attached to the cast material mesially and distally adjacent to the implants. Absolute mean strain development ranged from 29.35 Μm/m to 2,665.80 Μm/m at the different strain gauge locations. Fabrication method had a significant effect on strain development (multivariate analysis of variance, P = .000), with the cast restorations showing significantly higher strain levels compared to the CAD/CAM-fabricated superstructures. CAD/CAM fabrication of screw-retained implant-supported restorations provides greater passivity of fit compared to conventional fabrication methods such as casting.

A clinical study of edentulous patients rehabilitated according to the "all on four" immediate function protocol

PURPOSE

The aim of this study was to compare definitive acrylic resin prostheses with or without a cast metal framework that were immediately loaded and supported by axial and tilted implants in completely edentulous patients after 3 years of function.

MATERIALS AND METHODS

Patients who were completely or partially edentulous in one or both arches with severe atrophy of the posterior regions were selected for this study. All patients immediately received prosthetic rehabilitations, each supported by four implants (two axial and two tilted). The patients were randomized to receive a definitive prosthesis with a cast metal framework or one made of acrylic resin only. Follow-up visits were performed up to 36 months after implant insertion and included radiographic assessments of bone levels around the implants.

RESULTS

Thirty-six patients participated, and 44 complete-arch immediately loaded prostheses (24 maxillary and 20 mandibular), each supported by four implants (in total 176 implants), were placed. In all, 21 screw-retained full-arch acrylic resin prostheses and 23 cast-metal-framework prostheses were delivered to the patients. The 3-year overall implant survival rate was 100% for axially positioned implants and 96.59% for tilted implants. Implant survival rates were 98.96% in the maxilla and 97.5% in the mandible. None of the 44 fixed prostheses were lost during the observation period, representing a prosthetic survival rate of 100%. No statistically significant differences were seen in crestal bone loss between tilted and axial implants at 12, 24, and 36 months in either arch.

CONCLUSIONS

The same clinical outcome was seen for patients treated with the so-called All on Four protocol, regardless of whether the acrylic resin restorations were reinforced with metal.

Prosthetic aspects and patient satisfaction with resilient liner and clip attachments for bar- and implant-retained mandibular overdentures: a 3-year randomized clinical study

PURPOSE

This report aimed to compare prosthetic aspects and patient satisfaction during a 3-year randomized clinical trial of bar- and implant-retained mandibular overdentures attached with either resilient liners or clips.

MATERIALS AND METHODS

Thirty edentulous male patients (mean age: 62.5 years) received two implants in the anterior mandible after being allocated into two equal groups (according to attachment type received) using balanced randomization. After 3 months, implants were connected with resilient bars. New maxillary complete dentures were then constructed, and mandibular overdentures were retained to the bars with either clips (group I) or silicone resilient liners (group II). Subjects indicated satisfaction with their prostheses using a questionnaire and visual analog scale. Patient satisfaction and prosthetic complications were recorded for both attachments at 6 months and 1 and 3 years after overdenture insertion.

RESULTS

Comfort and stability with the maxillary denture and ease of hygiene procedures were rated higher in group II, while ease of handling the dentures was rated higher in group I. No significant differences in other parameters of patient satisfaction between groups were noted after 3 years. The mean number of prosthetic adjustments and repairs in group I (11.9) was significantly higher (P = .00) compared to that in group II (4.8). The most common complication in group I was clip wear, while separation of the resilient liner from the denture base was the most common problem in group II. Hyperplasia under the bar and flabby ridge in the maxilla occurred significantly more often in group I compared to group II.

CONCLUSIONS

Resilient liner-retained mandibular overdentures had comparable patient satisfaction, less prosthetic maintenance and costs, and less soft tissue complications when compared to clip-retained ones after 3 years.

Tilted implants to support a maxillary removable dental prosthesis: a case report

The placement of implants in a tilted position may provide a viable treatment modality, especially for patients with atrophic maxillae. The treatment steps and procedures for a maxillary implant-supported removable dental prosthesis, as well as a mandibular telescopic crown-retained removable dental prosthesis, are described. The concept of tilted implants via 3D planning and flapless surgery is presented. The final outcome facilitated improvement in the patient's satisfaction and comfort, as well as long-term stability of the implants and prosthesis. In addition, there was a reduction in cost by avoiding augmentation procedures.

Design of removable partial dentures: a survey of dental laboratories in Greece

The aim of this study was to compare data on design and fabrication methods of removable partial dentures (RPDs) in two major cities in Greece. A questionnaire was sent to 150 randomly selected dental technicians. The participation rate was 79.3%. The anterior palatal strap, the lingual bar, and the Roach-type clasp arm designs were preferred. Half of the RPDs fabricated were retained using precision attachments. Differences between the two cities were observed in types of major maxillary connectors used, types of attachments and impression materials used, as well as the design of distal-extension RPDs. Postdoctoral education was found to have an impact on RPD fabrication. Despite the differences observed, design and fabrication of RPDs followed commonly used principles.

Immediate loading of two unsplinted implants retaining the existing complete mandibular denture in elderly edentulous patients: 1-year results from a multicentre prospective cohort study

PURPOSE

To evaluate the outcome of two freestanding implants immediately loaded retaining an existing mandibular complete denture in elderly edentulous patients up to 1 year after loading.

MATERIALS AND METHODS

42 patients with a mean age of 76.5 years (range 71 to 89) were selected for stabilising their mandibular complete denture with two implants placed mesial to the mandibular canine position bilaterally. Individual ball abutments were connected and torqued at 30 Ncm and the existing complete denture was immediately attached. No postoperative limitations to chewing function were given. The patients were evaluated clinically and radiographically at implant placement and at 6- and 12-month follow-up examinations.

RESULTS

At the 12-month follow-up no implant failed. Peri-implant bone resorption was 0.203 mm (CI 95% 0.322; 0.086) after 6 months and 0.298 mm (CI 95% 0.425; 0.173) after 12 months. Of the 42 cases, 3 had major prosthetic complications and 5 patients required minor extra maintenance appointments.

CONCLUSIONS

Within the limits of this study, it can be suggested that the immediate loading of two unsplinted implants retaining the existing complete mandibular denture in elderly patients can result in favourable implant survival and peri-implant bone healing, however larger and longer follow-ups of 5 years or more are needed.

Immediate loading of 2 (all-on-2) flapless-placed mandibular implants supporting cross-arch fixed prostheses: interim data from a 1-year follow-up prospective single cohort study

PURPOSE

To evaluate the clinical outcome of 2 implants placed flapless in fully edentulous mandibles and immediately restored with a metal-resin screw-retained cross-arch prosthesis 1 year after loading.

MATERIALS AND METHODS

Eighty consecutive patients were recruited. To be immediately loaded, implants had to be inserted with a minimum torque of 80 Ncm. Outcome measures, evaluated by two independent assessors, were prosthesis and implant failures, complications, marginal bone level changes, implant stability quotient (ISQ) values and patient satisfaction.

RESULTS

Flaps were raised in 7 patients. Twelve implants in 7 patients did not reach the planned insertion torque. Four implants in 3 patients were immediately replaced by larger diameter implants and achieved the desired torque, whereas the remaining implants were immediately loaded anyway. Two implants failed early in 2 patients, but were successfully replaced and their prostheses remade. One month after loading, 72 (90%) patients declared to be completely satisfied with the therapy, 7 (9%) partially satisfied and 1 (1%) unsatisfied. One year after loading, all prostheses were in function, though one patient did not attend the 1-year control. Eight (10%) complications occurred, all successfully treated. After 1 year, the mean marginal bone loss was 0.3 mm and mean ISQ values decreased from 75.4 to 72.4.

CONCLUSIONS

These short-term results at 1 year after loading suggest that immediately loaded mandibular cross-arch fixed prostheses can be supported by only 2 dental implants. Longer follow-ups (around 10 years) are needed to know the prognosis of this treatment modality.

Short-term objective and subjective evaluation of small-diameter implants used to support and retain mandibular prosthesis

BACKGROUND

The introduction of small-diameter implants has provided dentists the means of providing edentulous and partially edentulous patients with immediate functioning transitional prostheses while definitive restorations are being fabricated. The successful use of these small-diameter implants for temporary stabilization of prostheses has led many clinicians to explore the option of using them as a definitive alternative, especially as the technique requires minimal time and also is economical for the patients. To date, there has been no study with multiple patients looking at both the subjective and objective outcomes of these small-diameter implants.

MATERIALS AND METHODS

Twenty-seven edentulous patients were enrolled in this study, seven of them were smokers. One-hundred and eight small-diameter (2.0 mm, MDL) implants were surgically placed in 24 edentulous mandibles. All implants were immediately loaded. The patients filled out a screening questionnaire and four subsequent questionnaires to test their satisfaction with the altered prosthesis at 6, 12, 18 and 24 months. The survival of the implants was also noted.

RESULTS

Smokers had an implant survival of 79%. Non-smokers had an implant survival of 100%. The results of the questionnaire indicated an overall satisfaction with the implant-supported prosthesis.

Immediate loading of unsplinted implants in the anterior mandible for overdentures: 3-year results

PURPOSE

This 3-year study evaluated the implant survival rate, peri-implant tissue response, prosthetic maintenance, and prosthetic complications in a series of patients who received two immediately loaded unsplinted threaded implants to retain a mandibular overdenture.

MATERIALS AND METHODS

Eight completely edentulous patients were evaluated clinically and radiographically immediately after implant placement, at 3 months, and at 1, 2, and 3 years after implant placement. Data were analyzed using repeated-measures one-way analysis of variance and the Wilcoxon signed rank test at a significance level of α = .05.

RESULTS

At 3 years, all implants remained osseointegrated (16/16), with an overall mean marginal bone change of -0.58 ± 0.39 mm and a mean Periotest value of -7.19 ± 0.54. The modified Plaque Index scores showed marked improvement in oral hygiene during the first year, but some relapse was observed thereafter. Prosthetic maintenance and complications included replacement of the attachment inserts, abutment loosening, dislodgement of the attachment housing, overdenture reline, denture tooth fracture, and overdenture base fracture.

CONCLUSIONS

This 3-year study suggests that, despite less than ideal oral hygiene and a high incidence of complete/partial fracture of overdentures, favorable implant survival rate and peri-implant tissue responses can be achieved in mandibular overdentures retained with two immediately loaded unsplinted threaded implants.

Clinical and radiographic evaluation of three-implant-retained mandibular overdentures: a 3-year retrospective study

OBJECTIVE

To evaluate three-implant-retained mandibular overdentures after 3 years in terms of success rates, maximum occlusal force (MOF), marginal bone loss around implants (MBL), patient satisfaction, and quality of life (QoL).

METHOD AND MATERIALS

Twenty-three edentulous adults with maxillary complete dentures who received three-implant-retained mandibular overdentures with ball or bar attachments by the same surgeon over a 1-year period were evaluated 3 years after overdenture loading. Subjects were asked to grade their three-implant-retained mandibular overdentures on a visual analog scale and to complete the short-form Oral Health Impact Profile (OHIP-14) to evaluate satisfaction and QoL. MBL was evaluated using panoramic radiography. MOF with and without implant support was recorded using a strain gauge. Overall success was measured by absence of mobility, peri-implant radiolucency, pain and paresthesia, and progressive MBL.

RESULTS

The overall success rate of implants was 100%. MBL around center implants was lower than around implants on the right and left sides (P = .001 and P =.03, respectively). MOF without implant support was lower than with implant support (P =.001). There was no association between attachment type and either MBL, MOF, satisfaction, or QoL (P > .05).

CONCLUSION

The excellent outcomes for three-implant-retained mandibular overdentures indicate that, regardless of attachment type, three-implant-retained mandibular overdentures opposing complete dentures are a successful treatment option for edentulous adults.

Long-term outcome of cemented versus screw-retained implant-supported partial restorations

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.

Chairside method for incorporating metal O-ring attachment in mandibular implant-retained overdenture

Use of an implant-retained overdenture for the mandible is associated with a high success rate. After osseointegration, connecting the implants to the lower denture is an important step in achieving successful treatment. Different methods and attachment systems described in the literature may require a high level of laboratory support. This article describes a chairside method for connecting the O-ring attachment to the implant-retained mandibular denture.

Use of a powered toothbrush for hygiene of edentulous implant-supported prostheses

Effective professional maintenance and personal oral hygiene are important for the long-term success and comfortable functioning of implant-assisted dental restorations. Incorporating the most effective oral hygiene devices into each patient's oral hygiene regimen facilitates optimal results. The use of a powered toothbrush with interchangeable brush heads permits effective cleaning of the most access-challenging prosthesis contours. This article presents a useful personal oral hygiene regimen for the long-term maintenance of various implant-supported dental restorations.

Development of a self-adjusting magnetic attachment for implant overdentures

This study aimed to clarify the efficacy of a newly developed self-adjusting magnetic attachment (SMAT) that allowed 0.4 mm of vertical and 8 degrees of rotational movements using an in vitro model. Comparison between the SMAT and a conventional magnetic attachment (CMAT) was performed for the retentive force under different dislodgement directions. Lateral forces to the abutment were also compared among the SMAT, CMAT, dome-shaped magnetic attachment, and a ball attachment. The SMAT maintained retentive force more effectively than the CMAT, even in oblique directions of dislodgement. A smaller lateral force to the abutment was found for the SMAT compared to the CMAT or ball attachment.

Comparison of ball and telescopic crown attachments in implant-retained mandibular overdentures: a 5-year prospective study

PURPOSE

Implant success, peri-implant conditions, and prosthodontic maintenance requirements were evaluated and compared for mandibular overdentures supported by two implants and retained with ball or resilient telescopic crown attachments during a 5-year period.

MATERIALS AND METHODS

Twenty-five patients with an edentulous mandible each received two root-form dental implants in the mandibular interforaminal (canine) region. The type of denture attachment was chosen randomly; 13 patients received ball attachments and 12 patients received resilient telescopic crowns. Implant success and peri-implant conditions (bone resorption, pocket depth, Plaque Index, Gingival Index, Bleeding Index) as well as prosthodontic maintenance and patient satisfaction were evaluated annually during a 5-year follow-up period and compared with respect to the two retention modalities used.

RESULTS

Implant success, peri-implant conditions, and subjective patient satisfaction scores did not differ between the two retention modalities used. However, during the 5-year observation period, significantly more postinsertion complications/interventions for maintenance purposes were registered in the ball group (87 interventions, 61.1%) than in the telescopic crown group (53 interventions, 37.9%; P < .01). Differences in prosthodontic maintenance efforts were most significant in the second and third years (P < .05) of the follow-up period but were similar at the end of the study for both anchorage systems.

CONCLUSION

Both ball attachments and resilient telescopic crowns on isolated implants in the atrophic mandible are viable treatment options for implant-supported overdentures. No implant losses, good peri-implant conditions, and general patient satisfaction were noted. Although the frequency of technical complications was initially higher with ball attachments than with resilient telescopic crowns over a 5-year period, similar frequencies of maintenance efforts may be anticipated for both retention modalities.

Clinical performance and material properties of single-implant overdenture attachment systems

PURPOSE

The aim of this study was to evaluate the mechanical properties of different attachment systems used for mandibular single-implant overdentures and to compare their wear/deformation features with clinical performance in patients after 1 year.

MATERIALS AND METHODS

Three attachment systems were evaluated: large 5.9-mm titanium nitride-coated ball attachments with plastic matrices, standard 2.25-mm uncoated titanium alloy ball attachments with Dalla Bona-type gold alloy matrices, and Locator attachments of titanium nitride-coated patrices and nylon matrices. The hardness and elastic modulus of the systems were determined using the nanoindentation technique. Twelve attachments from each system were used in 36 edentulous patients to support mandibular single-implant overdentures. After 1 year, 5 samples from each system were retrieved and evaluated for wear changes under a scanning electron microscope.

RESULTS

The titanium nitride-coated patrices, regardless of system, appeared unchanged and did not require any maintenance. Extensive wear was evident in the uncoated titanium alloy patrices and Dalla Bona-type gold alloy matrices, resulting in high maintenance (15 activations). Minimal wear was observed in the plastic matrices with minimal maintenance (2 replacements). The Locator nylon matrices showed extensive deformation and deterioration with a substantial need for maintenance (16 replacements). The performance of the patrices was related to hardness, while that of the matrices was related to the creep response.

CONCLUSIONS

Large ball attachment systems of titanium nitride-coated patrices and plastic matrices reflect favorable wear behavior and clinical performance. These attachments are recommended for patients receiving mandibular single-implant overdentures.

Maintenance of implant-supported maxillary prostheses: a 2-year controlled clinical trial

PURPOSE

To analyze maintenance service of fixed maxillary prostheses and overdentures based on conventional gold bars or titanium bars and frameworks fabricated with computer-aided design/computer-assisted manufacture (CAD/CAM) technology.

MATERIALS AND METHODS

Forty-one patients participated; 16 received an implant overdenture with a gold bar (gold OD), 12 received a CAD/CAM-fabricated implant OD with a titanium bar (Ti OD), and 13 received a CAD/CAM implant-supported fixed prosthesis (IFP). The bars and frameworks were screw-retained at the implant level. Maintenance service performed during the first 2 years was recorded and compared between the three groups. After this 2-year period, the Oral Health Impact Profile (OHIP) was administered.

RESULTS

For ODs (gold, Ti) most service consisted of activation of the matrices. Fractures of matrices and bar extensions occurred only in the gold OD group, and 65% of these patients exhibited hyperplasia of the peri-implant mucosa. The maintenance rates were 1.24 (gold OD), 1.36 (Ti OD), and 0.98 (IFP). These differences were not statistically significant. Retightening of occlusal screws was not necessary in any group. The probability that a complication occurred in the first year was high (60% to 70%) and statistically not different between the three groups. The probability that a second complication occurred was significantly lower for the IFP group versus the gold OD group. The mean OHIP values were 1.7 (IFP), 6.7 (gold OD), and 7.3 (Ti OD); ratings in the IFP group were significantly better.

CONCLUSIONS

Maintenance service was typical for implant prostheses in the edentulous maxilla. Direct screw retention at the implant level without abutments had a favorable effect in all groups. A trend toward a reduction in problems was observed with the CAD/CAM superstructures. The OHIP confirmed high satisfaction, but quality of life appeared to be slightly higher with fixed prostheses.

Five-year treatment outcomes with four types of implants in the posterior maxilla and mandible in partially edentulous patients: a retrospective study

PURPOSE

The aim of this retrospective study was to evaluate the outcomes, after 5 years of functional loading, of four different types of implants supporting prostheses in the posterior maxilla and mandible.

MATERIALS AND METHODS

Patients missing posterior teeth were treated with implants between 1998 and 2004. The implants were evaluated by clinical and radiographic parameters and Plaque Index, Sulcus Bleeding Index (BI), peri-implant probing depths (PD), and marginal bone loss (MBL) were recorded. Repeated-measures analysis of variance, Kruskal-Wallis, and Wilcoxon signed rank tests were used for statistical analysis.

RESULTS

In all, 244 implants were placed in 83 patients: 86 Straumann implants, 35 Swiss Plus implants, 90 Camlog implants, and 33 Frialit implants. Patients received 93 single crowns and 71 fixed partial dentures (FPDs). Nine FPDs were cemented to both implants and natural teeth, and 62 FPDs were supported by implants only. At the 5-year recall, plaque accumulation was significantly higher than at baseline for all groups (P = .01). Mean PD was 1.8 mm in the maxilla and 1.6 mm in the mandible. The mean PD values were 1.77 ± 0.52 mm for Straumann, 1.87 ± 0.64 mm for Swiss Plus, 2.33 ± 0.58 mm for Camlog, and 2.29 ± 0.46 mm for Frialit. MBL was 0.19 ± 0.07 mm for Straumann, 0.27 ± 0.06 mm for Camlog, 0.26 ± 0.07 mm for Swiss Plus, and 0.24 ± 0.07 mm for Frialit. The mean MBL of Straumann implants was significantly lower than that seen in the other groups (P = .001).

CONCLUSION

The four types of implants resulted in similar clinical success after 5 years.

Telescopic magnetic attachment for implant-supported denture: evaluation of splint effect

PURPOSE

Retrievability, connecting strength, and ease of laboratory work are important but conflicting prerequisites for the success of an implant superstructure, particularly with regard to immediate function. To resolve this issue, a telescopic magnetic attachment system has been developed for implant-supported removable dentures. The splinting effect of the attachment was evaluated for stress distribution and elevation with an in vitro model of three implants in an edentulous mandible.

MATERIALS AND METHODS

Two types of telescopic magnetic attachments were prepared; the inclination angles of the axial wall of the abutment were 2.5 and 6.0 degrees. Three types of three-unit superstructures--a screw-retained superstructure and two telescopic magnet-retained superstructures--were fabricated. Static loads of 24.5, 49, and 98 N were applied vertically at three loading points on one side of each occlusal table. The elevation was measured as the height at which the magnet-retained superstructure detached from the abutment (on the other side of the prosthesis). In addition, by means of strain gauges, the stress distribution around the implants was evaluated and compared among the superstructures with the same three loads applied at six different points.

RESULTS

The magnet-retained superstructure with the axial wall inclined at 2.5 degrees did not detach from the abutment. The differences in stress distribution between the screw-retained and magnet-retained superstructures with a 2.5-degree inclination were found to be statistically insignificant. The magnet-retained superstructure with a 6-degree inclination detached from the abutment, and the stress was concentrated during loading to a cantilever site.

CONCLUSION

Because of its stress distribution and elevation, the new telescopic magnetic attachment, which has properties such as splinting the implants, ease of fabrication, and retrievability, is expected to be a viable alternative for the retention of implant-supported removable dentures.

A 36-month randomized controlled split-mouth trial comparing immediately loaded titanium oxide-anodized and machined implants supporting fixed partial dentures in the posterior mandible

PURPOSE

A single-blind randomized controlled split-mouth trial was performed to compare the 36-month outcomes of machined and titanium oxide-anodized (ADZ) dental implant surfaces immediately loaded with fixed partial dentures in the posterior mandible.

MATERIALS AND METHODS

Ten patients with bilateral partial edentulism in the posterior mandible received 42 implants; 20 were placed on the test side (ADZ) and 22 were placed on the control (machined) side. The implants were loaded within 24 hours after placement. Changes in the radiographic bone level (RBL) were measured on standardized periapical films at baseline, 12 months, and 36 months. The mean changes in RBL were compared using a paired t test, and the mean changes in RBL with regard to implant position and implant surface type were compared via two-way analysis of variance.

RESULTS

After 36 months of functional loading, the overall cumulative success rate for all implants was 95%. The mean change in RBL at 36 months was 0.35 mm and 0.32 mm for ADZ and machined implants, respectively (not statistically significantly different between groups; P = .88). A reduction in RBL was observed for both machined and ADZ implants between 12 and 36 months, but only the machined implants demonstrated a statistically significant decrease in RBL during the observation period.

CONCLUSIONS

No statistically significant differences in RBL change were found between machined and ADZ implant surfaces after 36 months in function, and both surfaces demonstrated minimal marginal bone remodeling. As such, immediate loading of ADZ and machined dental implants supporting fixed partial dentures may be a suitable long-term treatment option in the posterior mandible.

Wear of ball attachments after 1 to 8 years of clinical use: a qualitative analysis

The purpose of this study was to analyze and compare scanning electron microscopy (SEM) observations of ball attachments that had been worn by patients during three periods of clinical use. One hundred forty-four specimens of ball anchor attachments (gold alloy matrix and titanium patrix) were studied by SEM after periods of approximately 1, 3.5, and 8 years of clinical use. Twenty new attachment components were examined as controls. SEM images revealed signs of mechanical wear for the ball attachments studied. The surfaces of the titanium patrix were associated primarily with roughening after short-term use, whereas surfaces of the gold alloy matrix showed wear, roughening, and loss of microscopic material in the form of flakes. Severe mechanical wear on both surfaces was noted after longer periods of use. The mechanical changes were not correlated with patient-mediated observations regarding the time-dependent retentive efficacy of the attachments. One year of clinical wear appeared to have limited effect on the ball attachment tested. Conversely, longer periods of use led to marked modifications in shape of the matrix and patrix components.

Treatment concept of the edentulous mandible with prefabricated telescopic abutments and immediate functional loading

PURPOSE

The present paper demonstrates a new technique and long-term results of a treatment concept that uses four implants placed in the anterior mandible that are connected to prefabricated telescopic abutments and immediately loaded with removable restorations.

MATERIALS AND METHODS

The present retrospective study included 488 implants (Ankylos, Dentsply) placed in 122 patients (mean age: 65.2 ± 9.8 years) with clinical and radiographic evaluation for a period of at least 1 year. Eighty-four implants were placed in fresh extraction sockets and combined in the restorations with implants placed in healed ridges. All implants were placed 2 mm subcrestally (based on chart documentation, measured from the midfacial bone level). The implants were connected immediately after surgery to conical prefabricated abutments (angle of 4 to 6 degrees) using a final torque of 15 Ncm. Secondary prefabricated copings that fit the abutments were placed over the abutments after abutment connection, and the complete denture of each patient was relined chairside with methyl methacrylate resin. The prosthetic restorations were to remain in place for 10 days to ensure that the implants remained immobile.

RESULTS

After a mean of 79 ± 29.8 months (range, 17 to 129 months) only eight implants failed (1.6%). Twenty-one implants (4.3%) showed crestal bone loss greater than 2 mm relative to the implant position at the time of implant insertion. Therefore, the failure rate was 5.94% for the entire observation period. The success rate for the evaluated implants was 94.06%. The patients were satisfied with the stability of their prostheses, and no prosthetic or peri-implant problems were observed.

CONCLUSIONS

These telescopic implant-supported restorations with immediate loading seem to be an alternative prosthetic solution for the edentulous patient, providing long-term implant stability.