The use of a dental implant as an abutment in three unit implant-tooth supported fixed partial denture: a case report and 32 month follow-up

The combined use of dental implants and teeth as abutments in fixed partial dentures may offer advantages to both patients and practitioners in certain clinical situations. An implant-tooth retained prosthesis may reduce surgical intervention and cost to the patient. It may also mean that anatomical restrictions to the provision of an implant-retained fixed prosthesis may be overcome. In this case report, the steps in provision of a three unit implant-to-tooth fixed partial denture are described and the treatment planning and prognosis of a restoration of this type are discussed.     

A 5‐year prospective clinical study of Astra Tech dental implants supporting fixed bridges or overdentures in the edentulous mandible

In a 5‐year prospective clinical study, 1.55 endosseous implants were installed in the mandible anterior to the mental foramina in 33 edentulous patients (13 males and 20 females). Usually 6 implants were installed for fixed prostheses (FP). 13 patients with 77 implants, and 4 implants for overdentures (OD) with a Dolder bar, 20 patients with 78 implants. At the time of abutment connection 1 implant in 2 patients was found to be loose and removed. However, in both these patients overdentures were successfully placed on the remaining 3 implants. Narrow‐beam radiography was used for radiological evaluation. The mean (SD) total marginal bone loss in 5 years was 0.48 (0.38) mm (0.36 (0.22) mm in the FP group and 0.56 (0.45) mm in the OD group). Very few complications were reported during the 5 years, most of them being related to the superstructures. The overall cumulative implant survival rate was 98.7%(100% in the FP group and 97.4% in the OD group). The survival rate of the superstructures was 100%. The present study has demonstrated that Astra Tech implants offer reliable and predictable medium‐term support for fixed prostheses and overdentures in the edentulous mandible.     

Patient's opinion and treatment outcome of fixed rehabilitation on Brinemark implants. A 3‐year follow‐up study in private dental practices.

In this study, patient opinion on oral rehabilitation by means of Brånemark implants was investigated. All patients were referred to a periodontal clinic for implant installation and treated by one and the same operator. Prosthetic restorations were performed by dentists, who had no previous experience with prostheses on implants, but had completed a postgraduate training course. Patient opinion was obtained through questionnaires, pertaining to satisfaction and oral function. A comparison was made between pre‐implant situation, short‐term (<4 months) and long‐term functioning )3 years( with the implant‐restorative rehabilitation. In total, 61 patients participated in the study; 23 received a full lower arch bridge and 18 a full upper arch bridge, while 20 patients got partial bridges. Of 298 installed implants, 7 failed at abutment connection (2.3%) and 1 during the 3‐year follow‐up interval (0.3%). The study results indicated that a great majority of patients were very satisfied with the treatment. Comfort with eating, aesthetics, phonetics and overall satisfaction improved significantly and nearly all patients said that they would undergo the treatment again or recommend it to others. Patients experienced their implants as "natural" teeth. The conclusion is that rehabilitation ad modum Brånemark, even in the hands of non‐specialized dentists, can be of high quality, improving oral function and satisfying the needs and demands of patients.     

Bridges supported by free‐standing implants versus bridges supported by tooth and implant. A five‐year prospective study.

The clinical question at issue, whether it is possible to combine implants and natural teeth via fixed bridges, is of current interest. The treatment of the subjects of this prospective study was performed between June 1984 and December 1986. This article presents the 5‐year results of the study. The consecutive patient material comprised 23 patients with Applegate Kennedy Class I residual dentition in the mandible and a complete maxillary denture. All 23 patients were provided with implants ad modum Bråemark in each mandibular quadrant. One side was randomized to rehabilitation with fixed bridge between the distal tooth of the residual dentition and an implant; the other side received a free‐standang bridge on2 implants. The fixture survival rate was 88%. No difference was found between the two sides. Bridge stability was 89% for the implant bridges and 91% for the combination bridges. The change in marginal bone level at the implants was small during the 5‐year follow up period (on average 0.1–0.3 mm) and with no difference between the two sides. In conclusion, it was not possible to demonstrate any higher risk of implant or prosthetic failure for tooth‐implant fixed bridges compared with implant‐supported bridges.     

A prospective 5-year study of fixed partial prostheses supported by implants with machined and TiO2-blasted surface

Purpose The aim of the present study was to evaluate whether there was a difference between machined and TiO₂‐blasted implants regarding survival rate and marginal bone loss during a 5‐year observation period. Materials and Methods A total of 133 implants (Astra Tech Dental Implants; Astra Tech AB, Mölndal, Sweden) were placed in 50 patients at 6 centers in 4 Scandinavian countries. Forty‐eight implants were installed in the maxilla and 85 implants in the mandible. A randomization and a stratification were done, so that each fixed partial prosthesis was supported by at least 1 machined and 1 TiO₂‐blasted implant. The implant‐supported fixed partial prostheses (ISFPP) were fabricated within 2 months after postoperative healing. A total of 52 ISFPP (17 maxillary, 35 mandibular) were inserted. The patients were clinically examined once a year for 5 years. At the annual follow‐up, biological as well as technical complications were recorded. Results Of the 133 implants placed, 3 were reported as failed after 5 years of follow‐up, resulting in an overall cumulative survival rate of 97.6%. The cumulative implant survival rates were 100% for the TiO₂‐blasted implants and 95.1% for the machined implants. No significant difference in survival was, however, found between the machined and TiO₂‐blasted implants after 5 years. The mean marginal bone loss in the maxilla was 0.21 ± 0.83 mm (SD) for the machined implants and 0.51 ± 1.11 mm (SD) for the TiO₂‐blasted implants during the 5‐year observation period. In the mandible, the mean marginal loss was 0.22 ± 1.13 mm for the machined implants and 0.52 ± 1.07 mm for the TiO₂‐blasted implants from baseline to the 5‐year examination. No significant difference in marginal bone loss between the 2 surface groups was found during the 5‐year observation period. Conclusions The present study shows good 5‐year results with small ISFPP in the mandible, as well as in the maxilla. No significant differences were found in failure rate and marginal bone loss around implants with a machined rather than a TiO₂‐blasted surface.     

Speech in connection with maxillary fixed prostheses on osseointegrated implants: a three‐year follow‐up study

In 21 individuals, edentulous in the upper jaw, the speech function was evaluated. In an earlier study, registrations were made when the patients wore complete dentures in the upper jaw and 3-6 months after they had been treated with fixed prostheses on osseointegrated implants in the maxilla. These patients were re-examined after 3 years, as reported in this follow-up study. An expert group as well as a non-expert group participated in a perceptual analysis. Acoustic, audiological and cast analyses were performed. In addition, a questionnaire was filled in. The results indicated that, after initial phonetic problems, 94% of the individuals considered themselves free from speech problems at the 3-year follow-up. The patients' experience of the change of the s-sound corresponded well with the judgement of both the expert and the non-expert groups. Difficulties with pronouncing the s-sound were associated with decreased bite force, the number of occluding contacts, the frontal width of the fixed prosthesis and tenderness at palpation of the masticatory muscles. These oral functional factors will contribute to the s-sound production.     

A clinical and radiographic evaluation of fixed partial dentures (FPDs) prepared by dental school students: a retrospective study

In recent years, there has been an increasing interest in fixed partial dentures (FPD) quality, expected lifetime and possible reasons for failure. This study probed the FPD success rate and the relationship among various factors and their effect on FPD failure. Patients treated by dental students under supervision and installed FPDs were examined clinically and radiographically. A total of 247 FPDs were evaluated after a mean service period of 6.3 years (ranging from 1 to 25 years) after cementation. Caries was found to be the most frequent cause of failure and non-vital abutments decreased survival rates.     

A prospective 15‐year follow‐up study of mandibular fixed prostheses supported by osseointegrated implants. Clinical results and marginal bone loss.

In this prospective study 47 edentulous patients were treated with mandibular fixed prostheses supported by osseointegrated Brånemark implants and followed for 12 to 15 years. Three 1%) of the 273 inserted implants were lost, two before and one six years after placement of the fixed prosthesis. The cumulative success rate CSR) of the implants was 98.9% both after 10 and 15 years. None of the fixed prostheses was lost and at the last follow‐up, all patients had stable fixed prostheses in function (CSR 100%). The marginal bone loss around the implants was small, on average 0.5mm during the first post surgical year and thereafter about 0.05mm annually. More bone was lost around the anterior implants than around the most posterior ones. Smoking and poor oral hygiene had significant influence on bone loss, while occlusal loading factors such as maximal bite force, tooth clenching and length of cantilevers were of minor importance. It is concluded that the long‐term results of the mandibular implant treatment were extremely successful, regarding both the fixed prostheses and implant stability. Bone resorption around the implants, albeit limited, was influenced by several factors, smoking and oral hygiene appeared to be most important.     

Identification of risk factors for fracture of veneering materials and screw loosening of implant‐supported fixed partial dentures in partially edentulous cases

This retrospective study identified the risk factors for fracture of veneering materials and screw loosening of implant‐supported fixed partial dentures in partially edentulous cases. The study group included a total of 182 patients who were installed 219 suprastructures at the Fixed Prosthodontic Clinic of Okayama University Dental Hospital between February 1990 and March 2005 and were subdivided in two subgroups: 120 patients (149 facing suprastructures) were included in the subgroup to investigate the risk factors of fracture of veneering materials, and 81 patients (92 suprastructures) were included in the subgroup to identify the risk factors of abutment screw loosening. Each patient was followed up from the day of suprastructure installation until March, 2005. A Cox proportional hazards regression model was used to identify the risk factors related to technical complications, and eight factors were regarded as candidate risk factors. Screw retention was the significant risk factor for fracture of veneering materials, whereas connection of suprastructures with natural tooth was the significant risk factor for screw loosening. It was suggested that screw retention was a significant risk factor for the fracture of veneering materials, and connection of suprastructures with natural tooth was a significant risk factor for screw loosening. Future studies, involving dynamic factors (e.g. bruxism) as predictors as well, are more helpful to discuss the risk factor of fracture of veneering materials and screw loosening.     

Correlations between radiographic, clinical and mobility parameters after loading of oral implants with fixed partial dentures. A 2‐year longitudinal study.

The aim of the present study was to correlate the changes in the peri‐implant tissues occurring after functional loading of non‐submerged titanium implants and assessed by radiographic, clinical and mobility measurements. 11 patients with distal extension situations received 18 implants of the ITI® Dental Implant System. After a healing period of 3months, the suprastructures were fabricated and seated 5months post‐surgically. For the assessment of peri‐implant bone changes, standardized vertical bitewing radiographs with reproducible exposure geometry were evaluated using computer assisted densitometric image analyses (CADIA) and bone height measurements. Since the radiographic evaluations were performed at mesial and distal sites only, the clinical parameters from these implant aspects were included in the analysis. Clinical periodontal parameters modified for the use around implants were obtained, damping characteristics were expressed as Periotest® readings and standardized radiographs were obtained at 1, 3, 6, 12 and 24 months after loading. In addition, radiographs were also taken at the start of functional loading. The data obtained from this small sample of implants demonstrated a wide range of different tissue alterations when using radiographic. clinical and mobility assessments. The parameter of probing attachment level (PAL) in combination with radiographic parameters obtained at 1, 3 and 6 months after loading were good predictors for the peri‐implant tissue status at 2 years. This was shown by means of multiple stepwise regression analyses. Mobility measurements did not reveal valuable predictive information with the statistical models applied. Assessments of probing attachment levels using periodontal probes rendered information on peri‐implant tissue alterations, which were closely correlated to the radiographically measurable peri‐implant bone changes.     

Marginal bone levels at single tooth implants with a conical fixture design. The influence of surface macro‐ and microstructure

The concept of a conical implant design to accommodate single tooth replacement, has previously been shown to result in excessive bone loss, around the machined titanium conical collar, usually down to the 1st thread. This unusually aggressive loss of bone was shown to occur within a short period of time, post loading, with greater than 3 mm of bone loss occurring within the 1st 6 months to 1 year. The influence of implant design, surface texture and microleakage have all been highlighted as a potential cause. A modification of the surface structure, both at the macroscopic and microscopic level, as well as an altered fixture‐abutment interface design has resulted in the maintenance of marginal bone around a single tooth titanium implant with a similar conical design. The radiographic follow‐up of 33 implants loaded for up to 4 years, has revealed, by comparison, a most favourable maintenance of marginal bone around the conical collar, with a mean marginal bone loss of 0.32 mm mesially and 0.34 mm distally for the whole group. The cumulative mean marginal bone loss mesially and distally is 0.42 mm and 0.40 mm from 1 to 2 years, 0.54 mm and 0.43 mm from 2 to 3 years, 0.51 mm and 0.24 mm from 3 to 4 years, and 0.62 mm and 0.60 mm for implants past their 4 year recall.     

Marginal tissue response adjacent to Astra Dental Implants® supporting overdentures in the mandible. A 2‐year follow‐up study.

The aim of this study was to evaluate the marginal tissue response adjacent to implant supported overdentures. Twenty edentulous patients had 2 Astra Dental Implants® placed in the canine region of the lower jaw. New overdentures were retained by individual ball attachments in 11 patients and by a bar attachment in 9 patients. Periodontal registrations were recorded 0 months, 6 months, 12 months and 24 months after the overdentures were inserted. One of the 40 fixtures was lost at the stage of abutment connection. No fixtures were lost during the 2‐ to 4‐year observation period and no fixtures showed any periodontal signs of failure. At the 2‐year examination, no pocket depths adjacent to the implants exceeded 4 mm and no bone loss exceeded 3 mm. The mean annual bone loss was less than 0.2 mm during the first 2 years. The preliminary results from this limited study were promising and showed that two osseointegrated Astra Dental Implants® could successfully retain an overdenture in the lower jaw. However, long‐term observation is needed for a definate evaluation of this treatment concept.     

A histomorphometric evaluation of bone‐to‐implant Eontact on machine‐prepared roughened titanium and dental implants. A pilot study in the dog.

This investigation was performed to assess the bone‐to‐implant surface contact at fixtures of titanium that either had a standard machine prepared or a TiO₂‐blasted surface. Five beagle dogs were used in the experiment. Extractions of the premolars were performed in the maxilla. After 4 months of healing, 5 standard machine‐prepared fixtures and 5 prepared according to the TioBlast technique were inserted. Two months later another 5 "standard" and 5 TiO Blast‐prepared implants were inserted. Four months after the first fixture installation, the animals were killed and ground sections prepared from each implant site. Of the 20 implants installed, 19 were successfully incorporated. The mean bone‐to‐implant surface for "standard" fixtures was about 40% both at the 2 and 4 months observation interval. The corresponding figures for the TiO Blast‐prepared fixtures were similar during the first 2 months of observation, while subsequently the TioBlast‐prepared fixture surface seemed to stimulate to a more close bone‐to‐implant contact (65%) than the "standard" one.     

Some clinical and radiographical features of submerged and non‐submerged titanium implants. A 5‐year follow‐up study.

The present study reports on the results of a follow‐up examination of patient material, 5 years after the installation of the fixed supraconstruction. The patient group comprised 11 individuals. Briefly, a split‐mouth technique of treatment was used. In the right side of the mandible the traditional 2‐step surgical approach for implant installation was used. In the left jaw quadrant a l‐step surgical procedure was used. A clinical and radiographical examination was performed 5 years after the initial connection of the supra‐construction to the implants. At the 5 year follow‐up examination all 61 implants examined at the 1 month follow‐up were still in service and found to be clinically stable irrespective of the surgical procedure used. Furthermore, the results of the present clinical and radiographical follow‐up study demonstrate that the marginal bone level at implants placed anteriorly in the edentulous mandible and supporting fixed supraconstructions is stable between 18 and 60 months irrespective of whether placed according to a l‐step or 2‐step surgical procedure.