Maxillary implant-retained partial overdenture with Dolder bar attachment: a clinical report

This article describes a technique for maintaining a maxillary Kennedy III partial removable dental prosthesis design in a patient who had non-restorable failing abutments by replacing the abutments with dental implants. Two implants were placed immediately after extraction of the abutment teeth in the anterior maxilla. After the implants were fully integrated, a Dolder bar attachment was fitted onto the implants. A new maxillary partial removable dental prosthesis was fabricated using the implants and the remaining natural teeth as abutments to restore function and esthetics. With the aid of dental implants, this Kennedy III maxillary removable dental prosthesis design could provide additional retention and support by promoting cross-arch stability and tissue, implant and tooth support. The patient's satisfaction was significantly increased.

The Bond Strength of Resin Bonded Bridge Retainers to Abutments of Differing Proportions of Enamel and Composite

Four groups of specimens were constructed using bovine enamel and composite resin. After a period of ageing, the specimens were roughened and acid etched before they were cemented to air abraded base metal alloy beams with a universal resin cement. After further ageing, tensile peel testing was carried out using a Universal Testing Machine. The force required to produce failure increased as the amount of composite resin on the bonding surface of the abutment increased. This difference reached statistical significance (p < 0.5) when the abutments contained > 50% composite. The mode of failure was mixed on the majority of retainers. Within the limitations of the study, findings suggest that RBB retainers can be cemented to abutments restored with composite resin without a reduction in bond strength.

Prosthetic rehabilitation of an edentulous patient with an oronasal fistula

The presence of an oronasal fistula presents a challenge to maxillary complete denture fabrication because leakage of air from the nasal cavity through the fistula prevents the formation of an adequate border seal. Although surgical repair or dental implants are possible solutions, these options are invasive and sometimes not feasible. This clinical report illustrates an alternative prosthetic solution by integrating a small retentive component into a maxillary complete denture.

Short implants versus bone augmentation for placing longer implants in atrophic maxillae: One-year post-loading results of a pilot randomised controlled trial

PURPOSE

To evaluate whether short (5.0 to 8.5 mm) dental implants could be a suitable alternative to longer (at least 11.5 mm-long) implants placed in atrophic maxillae augmented with autogenous bone for supporting dental prostheses.

MATERIALS AND METHODS

Twenty-eight patients with fully edentulous atrophic maxillae, whom had 5 to 9 mm of residual crestal bone height which was at least 5 mm thick, measured using computerised tomography (CT) scans, were randomised into two groups either to receive 4 to 8 short (5.0 to 8.5 mm) implants (15 patients) or autogenous bone from the iliac crest to allow the placement of at least 11.5 mm-long implants (13 patients). Bone blocks and the windows at the maxillary sinuses were covered with rigid resorbable barriers. Grafts were left to heal for 4 months before placing implants which were submerged. After 4 months, provisional reinforced acrylic prostheses or bar retained overdentures were delivered. Provisional prostheses were replaced, after 4 months, by definitive screw-retained metal-resin cross-arch restorations. Outcome measures were prosthesis and implant failures, any complications, peri-implant marginal bone level changes and patient satisfaction. Patients were followed up to 1 year after loading.

RESULTS

All patients were rehabilitated with implant-supported prostheses but two patients dropped out from the augmented group. One bilateral sinus lift procedure failed for infection, although short implants could be placed. One implant failed in the augmented group versus two short implants in two patients (Fishers exact test P = 1.00; difference in proportions = 0.06; 95% CI -0.28 to 0.17). All failures occurred before loading. Significantly more complications occurred in augmented patients: eight complications occurred in 5 augmented patients (all of them complained of pain 1 month after bone harvesting from the iliac crest) versus no complications in the short implant (Fisher's exact test P = 0.013; difference in proportions = 0.38; 95% CI 0.11 to 0.65). Both groups presented a significant peri-implant marginal bone loss at 1 year after loading (P < 0.0001); -1.05 (0.20) mm for short implants and -1.01 (0.16) mm for the augmented group, respectively, with no statistically significant differences between the two groups (mean difference -0.04 mm; 95% CI -0.22 to 0.14; P = 0.59). All patients were fully satisfied with the treatment and would have it again.

CONCLUSIONS

This pilot study suggests that short implants may be a suitable, cheaper and faster alternative to longer implants placed in bone augmented with autogenous bone for rehabilitating edentulous atrophic maxillae, however, these preliminary results need to be confirmed by larger trials with follow-ups of at least 5 years.

Torque loss under mechanical cycling of long-span zirconia and titanium-cemented and screw-retained implant-supported CAD/CAM frameworks

OBJECTIVES

This study evaluated the screw joint stability after cyclic loading of implant-supported titanium and zirconia CAD/CAM frameworks for fixed dental prostheses (FDPs) with different retention methods.

MATERIAL AND METHODS

Twenty four one-piece frameworks supported by six threaded implants placed in the maxilla were fabricated using a CAD/CAM technique (NeoShape). Dry-pressed porcelain crowns were luted to the frameworks to standardize the specimens. The specimens were then divided into four groups (n = 6) according to framework material (titanium or zirconia) and retention method for the prosthesis (cement- or screw-retained): G1, Ti-cemented; G2, Ti-screw-retained; G3, Zr-cemented; and G4, Zr-screw-retained. A digital torque ratchet was used to assess the initial preload removal torque. Torque was then reapplied and the specimens were submitted to a 200 N cyclic load, at a frequency of 2 Hz, underwater in controlled temperature of 37°, and for 1 × 106 cycles. An opposing lower dental arch was fabricated using bis-acrylic resin to simulate occlusal contacts in centric. After cyclic loading, postload removal torque was measured. Preload and postload torque loss was expressed as a percentage of the initial load. Data were submitted to a linear mixed-effects model for statistical significance (α = 0.05) to evaluate the effect of cyclic loading in the screw torque loss used with frameworks of different materials and retention methods.

RESULTS

Significant screw torque loss (%) was found for the tested groups (before/after cyclic loading, respectively): G1 (39.77/61.83), G2 (37.57/50.96), G3 (34.87/54.10), and G4 (47.56/73.50) (P < 0.05).

CONCLUSIONS

The screw removal torque was significantly reduced for all groups in this study after cyclic loading the specimens. Screw-retained zirconia specimens presented the highest torque loss before and after the cyclic loadings compared with the other specimens that were tested.

Technical complications and failures of zirconia-based prostheses supported by implants followed up to 7 years: a case series

PURPOSE

To evaluate technical complications and failures of zirconia-based fixed prostheses supported by implants.

MATERIALS AND METHODS

Consecutive patients received zirconia-based single crowns (SCs) and fixed dental prostheses (FDPs) on implants in a private clinical setting between 2005 and 2010. One dentist performed all surgical and prosthetic procedures, and one master technician performed and coordinated all laboratory procedures. One-piece computer-aided design/ computer-assisted manufacture technology was used to fabricate abutments and frameworks, which were directly connected at the implant level, where possible. All patients were involved in a recall maintenance program and were finally reviewed in 2012. Data on framework fractures, chipping of veneering ceramics, and other technical complications were recorded. The primary endpoint was failure of the prostheses, ie, the need for a complete remake. A life table analysis was calculated.

RESULTS

A total of 289 implants supported 193 zirconia-based prostheses (120 SCs and 73 FDPs) in 127 patients (51 men, 76 women; average age: 62.5 ± 13.4 years) who were reviewed in 2012. Twenty-five (13%) prostheses were cemented on 44 zirconia abutments and 168 (87%) prostheses were screw-retained directly at the implant level. Fracture of 3 frameworks (1 SC, 2 FDPs) was recorded, and significant chipping resulted in the remake of 3 prostheses (1 SC, 2 FDPs). The 7-year cumulative survival rate was 96.4% ± 1.99%. Minor complications comprised 5 loose screws (these were retightened), small chips associated with 3 prostheses (these were polished), and dislodgement of 3 prostheses (these were recemented). Overall, 176 prostheses remained free of technical problems.

CONCLUSIONS

Zirconia-based prostheses screwed directly to implants are clinically successful in the short and medium term.

Immediate versus early loading of mini-implants supporting mandibular overdentures: a preliminary 3-year clinical outcome report

PURPOSE

The aim of this preliminary clinical report was to evaluate and compare the clinical outcomes of immediate and early loaded mini-implants (MIs) supporting mandibular overdentures.

MATERIALS AND METHODS

Thirty-six completely edentulous patients (20 men and 16 women) complaining of insufficient retention of their mandibular dentures were randomly assigned to two groups. Each patient received four MIs in the interforaminal area of the mandible using the nonsubmerged flapless surgical approach. In group 1 (G1), MIs were loaded with mandibular overdentures using the immediate loading protocol, while in group 2 (G2), MIs were loaded with overdentures using the early loading protocol. The cumulative survival rate was calculated using Kaplan-Meier analysis. Peri-implant health indices (Plaque Index/Bleeding Index), probing depths, and marginal bone levels were recorded for both groups after MI insertions and 6, 12, 24, and 36 months thereafter.

RESULTS

The cumulative implant survival rates were 91.7% and 96.7% for G1 and G2, respectively. G1 recorded significantly higher Plaque Index, Bleeding Index, and probing depths than G2 after 12 months, while other observation times demonstrated no significant difference between groups. Most of the recorded marginal bone loss occurred in the first year, and no significant bone loss was noted in subsequent years. After 6 months, marginal bone loss was significantly higher in G1 compared to G2, but no significant differences between groups were noted thereafter.

CONCLUSIONS

Within the limitations of this study's research design and duration of follow-up outcome analyses, immediate and early loading protocols showed good clinical results with favorable peri-implant tissue response 3 years after implant insertion. Early loading of MIs supporting a mandibular overdenture appears to be preferable to immediate loading.

A technique for relining bar-retained overdentures

This article describes a technique for relining a mandibular bar-retained overdenture that allows recording the soft tissue beneath the bar and makes it possible to replace or modify the retentive bar attachment simultaneously with the reline procedure.

Intraoral-extraoral combination prosthesis: improving retention using interconnecting magnets

Osseointegrated implants have been well documented for retaining an obturator prosthesis as well as a facial prosthesis. However, when the defect extends to both the facial area and the maxilla, it is difficult to rehabilitate those defects to the satisfaction of the patient, especially in cases where implants cannot be placed on both sites. This case report describes the use of magnets to connect two prostheses, thereby increasing retention and patient comfort.

Immediate versus delayed loading of dental implants in edentulous patients' maxillae: a 6-year prospective study

PURPOSE

This study compared the surgical protocol efficacy of immediate and delayed implant loading in edentulous maxillae opposed by natural or restored mandibular dentitions over an observational period of 6 years or longer. The selected outcome determinants included individual implant survival data, progressive measurements of peri-implant bone resorption, prosthodontic survival and success data, and report of complications.

MATERIALS AND METHODS

A convenience sample of 49 patients requiring fixed implant-supported maxillary prostheses was split into two groups. The test group (34 patients) was treated according to the Columbus Bridge Protocol, which prescribes the insertion of four to six implants, including distally tilted implants, and load within 24 hours. The control group (15 patients) was treated via a two-stage surgical protocol of 6 to 9 straight implants that were loaded a mean 8.75 months after stage-one implant surgery. Two hundred sixty implants (test: n = 163, control: n = 97) were placed, and all subjects were ultimately treated with screw-retained full-arch prostheses.

RESULTS

Two patients dropped out (one in the test group and one in the control group) by the time of the scheduled sixth annual visit. The other patients were followed up for 75.2 months (range: 72 to 90 months). At the 6-year follow-up, no differences in implant cumulative survival rates were found between groups. Significantly less bone loss was found in the test group (mean: 1.62 mm) compared with the control group (mean: 2.44 mm). All of the original prostheses were maintained throughout the study's observation period and were functioning satisfactorily at each patient's last recall appointment.

CONCLUSION

Patients who received immediate and delayed implant loading in their edentulous maxillae demonstrated similar survival outcomes. However, less marginal bone loss was recorded around the immediately loaded implants over the study's 6-year follow-up period.

A hinged two-part partial denture used in conjunction with severely tilted teeth: a case report

A two-part sectional denture can be a useful treatment option when the presence of severe hard tissue undercuts compromises the provision of a satisfactory conventional prosthesis. This article presents a case report illustrating the effective use of a hinged two-part denture in restoring a mandibular Kennedy Class IV edentulous area. A sectional denture approach was selected because of severe proximal and lingual undercuts.

A 3-year prospective clinical study of telescopic crown, bar, and locator attachments for removable four implant-supported maxillary overdentures

PURPOSE

To evaluate telescopic crown (TC), bar, and locator attachments used in removable four implant-supported overdentures for patients with edentulous maxillae.

MATERIALS AND METHODS

A total of 30 maxillary edentulous patients were enrolled in a 3-year prospective study. Ten patients (group A) were treated with overdentures supported by TCs, 10 patients (group B) with overdentures supported by bar attachments, and 10 patients (group C) with overdentures supported by locator attachments. A total of 120 implants were used to restore oral function. During the 3-year follow-up period, implant survival and success rates, biologic and mechanical complications, prosthodontic maintenance efforts, and patient satisfaction were evaluated.

RESULTS

All 30 patients were available for the 3-year follow-up and exhibited 100% implant survival and success rates. Peri-implant marginal bone resorption was not statistically significant for the three groups. There were lower plaque, bleeding, gingiva, and calculus indices in group C compared with groups A and B. The number of prosthodontic maintenance visits revealed eight complications in the TC group, seven complications in the bar group, and four complications in the locator group. However, there were no differences in the clinical effects of the overdentures in the three groups.

CONCLUSION

Within the limits of this prospective study, it was concluded that the locator system produced superior clinical results compared with the TC and bar attachments in terms of peri-implant hygiene parameters, the frequency of prosthodontic maintenance measures, cost, and ease of denture preparation. However, longer-term prospective studies are required to confirm these results.

A preliminary three-dimensional finite element analysis of mandibular implant overdentures

A treatment protocol that may lead to reduced mandibular posterior residual ridge resorption in patients with overdentures retained and supported by two interforaminal implants was investigated. The treatment included the addition of short implants in the posterior edentulous mandible for the presumed purpose of favorable provision of mechanical load stimulus to alveolar bone. Three-dimensional finite element analysis was used to model cited effective strains that may stimulate bone remodeling in two selected models. Based on this laboratory study, the addition of posterior short implants has a favorable effect in maintaining bone mass under implant retained overdentures.

A systematic review of implant-supported overdentures in the edentulous maxilla, compared to the mandible: how many implants?

BACKGROUND AND AIM

There is now overwhelming evidence from systematic reviews that a two implant overdenture is the first choice of treatment for the edentulous mandible. Conversely, consensus is lacking for implant-supported maxillary overdentures. Therefore, we systematically reviewed the treatment outcome of concepts used for implant-supported maxillary overdentures, focusing on the survival of implants, survival of maxillary overdentures and condition of the implant surrounding hard and soft tissues after a mean observation period of at least 1 year.

MATERIAL AND METHODS

MEDLINE (1950 to December 2013), EMBASE (1966 to December 2013) and CENTRAL (1800 to December 2013) were searched to identify eligible studies. Two reviewers independently assessed the articles using specific study design-related quality assessment forms.

RESULTS

Out of 195 primarily selected articles, 24 studies fulfilled the inclusion criteria. A metaanalysis showed an implant survival rate of 98.1% and overdenture survival of 99.5% per year in the case of ≥ 6 implants and a splinted (bar) anchorage. In the case of ≤ 4 implants and a splinted (bar) anchorage, implant survival rate and overdenture survival were 97.0% and 96.9% per year, respectively. In the case of ≤ 4 implants and a non-splinted anchorage (ball, locator, telescopic crown), implant survival rate and overdenture survival were 88.9% and 98.8% per year, respectively. The condition of the peri-implant tissues was not reported in most studies.

CONCLUSIONS

An implant-supported maxillary overdenture (all studies ≥ 4 implants) provided with a splinted anchorage is accompanied with a high implant and overdenture survival rate (both >95% per year), while there is an increased risk of implant loss when ≤ 4 implants with a non-splinted anchorage are used.

Use of implant-supported prostheses in edentulous mandibles among prosthodontists in Sweden

The aim of this study was to investigate the production of mandibular implant-supported fixed and removable prostheses among prosthodontic specialists in Sweden and to compare the results with findings in a similar study made in 2001 (17). Questionnaires regarding treatment with mandibular implant prostheses during 20011 were mailed to all specialists in prosthodontics in Sweden (n = 156, according to available data). Of the 156 questionnaires, 129 (83%) were returned and of those 114 were completed. The reported number of treatments with mandibular implant-supported prostheses varied much among the specialists. Fixed implant prostheses were more common than overdentures (means 11 and 3, median values 8 and 2, respectively). However, the range was large for both alternatives. Ten (9%) of the specialists reported no treatment with fixed implant prostheses while 29 (25%) had not made any implant overdenture during 2011. The most common anchorage system for overdentures in 2011 (as well as in 2001) was two un-splinted implants with ball attachments or Locator abutments. The most common reasons for choosing overdenture treatment instead of a fixed implant prosthesis in 2011 were the reduced cost and the patient's main wish to improve denture retention. A majority of the prosthodontists (58%) reported that patients with implant overdentures were as satisfied as those with fixed implant-supported prostheses, whereas 40% claimed they were less satisfied. Two respondents (2%) considered that overdenture patients were more satisfied than those with a fixed prosthesis. It can be concluded that the general attitude among Swedish prosthodontists towards implant overdentures has not changed much during the 10-year period between the present and the previous investigation.An overdenture is still a seldom-used option in implant treatment of patients with edentulous mandibles in Sweden. Instead, a fixed implant-supported prosthesis continues to be the preferred option,

Immediate loading of two flapless placed mandibular implants supporting cross-arch fixed prostheses: a 3-year follow-up prospective single cohort study

PURPOSE

To evaluate the clinical outcome of two implants placed flapless in fully edentulous mandibles and immediately restored with a metal-resin screw-retained cross-arch prostheses 3 years after loading.

MATERIALS AND METHODS

Eighty consecutively patients were recruited. Implants for immediate loading 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

Three years after loading, all prostheses were in function although one patient did not come back for the 1- and 3-year follow-ups. Two implants failed early in two patients, but were successfully replaced and their prostheses remade. Twelve complications occurred in 10 patients but were all successfully treated. After 3 years, mean marginal bone loss was 0.43 mm, mean ISQ values decreased from 75.4 to 75.3, and all but four patients were fully satisfied with the therapy. Four patients were partially satisfied because, lacking molars, they could not chew as they wished.

CONCLUSION

Immediately loaded mandibular cross-arch partial dentures can be supported by only two dental implants up to 3 years. Longer follow-ups (around 10 years) are needed to know the prognosis of this treatment modality.

A novel approach to implant screw-retained restorations: adhesive combination between zirconia frameworks and monolithic lithium disilicate

The use of zirconia is an esthetic alternative to metal for implant-supported frameworks, and it has increased primarily for its high biocompatibility, low bacterial surface adhesion, high flexural strength and high mechanical features. The zirconia frameworks in fixed prosthetic restorations that are supported by implants is commonly covered with hand-layered overlay porcelain. This technical procedure is highly esthetic but it can cause some complications, such as porcelain fractures. The purpose of this article is to introduce an innovative approach to create an esthetic fixed ceramic implant restoration to minimize and facilitate the repair of the mechanical complications, by combining the adhesive-cementation of lithium disilicate full coverage restorations on implant screw-retained zirconia frameworks.

Occlusion of artificial teeth in partial dentures in the "chewing center"--first exploratory population-based evaluations

Occlusal performance is a substantial determinant of the quality of dental prosthetic restorations. In the follow-up (SHIP 1) to the Study of Health in Pomerania (SHIP), a representative population of 3300 subjects was studied in the first exploratory evaluation of the occlusion of artificial teeth in the chewing center (first molar region) of partial dentures. A digital analysis of interocclusal records of habitual intercuspation position (ICP) was performed using the Greifswald Digital Analyzing System (GEDAS), a software package that identifies contact points as transparent areas. 562 subjects (280 men aged 61.7 ± 11.9 years and 282 women aged 60.7 ± 10.7 years) had maxillary removable partial dentures (RPDs), and 619 (271 men aged 65.0 ± 11.5 years and 348 women aged 62.4 ± 10.6 years) had mandibular RPDs. Most RPDs were retained with either attachment retainers (11.7% maxilla, 11.7% mandible), cast clasps (38.4% maxilla, 40.7% mandible), telescopes with double crowns (15.7% maxilla, 19.1% mandible), or wrought wire clasps (16.4% maxilla, 8.2% mandible). Some had a combination of different retention elements. The mean number of artificial teeth was 7.8 ± 2.9 in the maxilla and 7.5 ± 3.0 in the mandible. Only the artificial teeth (first molars) in mandibular partial dentures showed differences in the frequency of occlusal contacts between groups (chi-square test). Of these, telescopic crown-retained RPDs had the highest frequency of occlusal contacts (74.4% at tooth 36 and 77.1% at tooth 46), and wrought wire-retained RPDs had the lowest (48.4% at tooth 36 and 45.2% at tooth 46). The results for RPDs with a free-end saddle were comparable and analogous; contact frequencies for those with an interdental saddle did not differ significantly. Notably, the overall frequency of occlusal contacts was greater for tooth 46 (62.9%) than for tooth 36. In conclusion, when replacing teeth in the chewing center, particularly in the mandible, telescopic crown-retained RPDs offer a distinct advantage in terms of occlusal contacts and thus provide better occlusal stability.

Long and short term management of implant-supported mandibular overdentures

Common problems with the long term clinical use of implant-supported mandibular overdentures (ISMDs) include fractures of dentures, bars and clips, and reactivation of clips. Many general dental practitioners (GDPs) are reticent to be involved in the maintenance of ISMDs, especially if they have not had any further training or are unfamiliar with implant components and systems. This article highlights the need for the training of GDPs in maintenance and management of ISMDs as an increasing number of edentulous patients are being provided with ISMDs, resulting in an increasing need for the maintenance of the prosthesis in the primary care setting at a possible cost to the patient.

CLINICAL RELEVANCE

Implant-supported overdentures are becoming a common treatment option for edentulous patients, however, they are not without their clinical challenges, many of which can be easily rectified in a primary care environment, such as general practice.

Magnetic attachment for implant overdentures: influence of contact relationship with the denture base on stability and bending strain

This study evaluated how the contact height between the magnetic attachment and denture base influences stability and bending strain. An implant modified with strain gauges and a magnetic attachment mounted in an acrylic resin block were used to characterize systems with varying degrees or heights of contact with the abutment. Bending strain under lateral loading increased significantly as the contact height decreased. In the no contact and resilient contact groups, magnetic assemblies separated at reduced bending strain in all loading conditions. The contact height of the magnetic attachment influenced the stability and the amount of bending strain on the implant.

In vitro retention loss of attachment-retained removable partial denture

AIM

To investigate the importance of attachment types on the retention loss of extracoronal attachment-retained removable partial dentures depending on the usage period.

MATERIALS AND METHODS

In order to observe the retention loss of 5 different attachments (OT Strategy, OT Strategy-metal protected, Vario-stud-snap and Vario-soft 3 and ERA-RV) over time, attachment-retained partial dentures representing Kennedy II mod. I case were placed in a custom-made, retention test machine. For each minute, eight separating and joining movements were performed and retention values (Newton) of the attachments were recorded by computer. The retention tests implemented in 540,1080 and 2160 cycles. The data were evaluated statistically according to the two-way ANOVA and Tukey parametrical tests.

RESULTS

The slide type attachment providing the best retention force was observed to be the most worn out by this process (p < 0.01) while the ball type attachments, which typically have the lesser retention force, showed less retention loss (p < 0.01).

CONCLUSION

It can be concluded that the retention attributes of the attachment-retained dentures were affected by the specific type of precision attachment as well as the usage period.

CLINICAL SIGNIFICANCE

Precision attachments with ball-type plastic matrices may be recommended for the clinical use due to their retention stability over time.