Zirconia abutments for single-tooth implant restorations: a 10- to 11-year follow-up study.

OBJECTIVES: To evaluate the clinical outcome of custom-made zirconia abutments for implant-supported single-tooth restorations 10-11 years after insertion. MATERIAL AND METHODS: The study comprises a clinical examination of 23 patients with 30 restorations placed 10-11 years ago. Oral surgeons placed the implants. The prosthodontic treatment was provided at a prosthodontic specialist clinic. The restoration was either an all-ceramic crown for cementation or a screw-retained one-piece restoration with the veneering porcelain baked directly to the zirconia abutment. Besides the clinical and radiographic examination at the 10- to 11-year follow-up, the patients' records were scrutinized regarding clinical and radiographic data from insertion of the restoration up to the last visit at the clinic. RESULTS: The zirconia abutments performed well. Both technical and biological complications were rare; most patients were in general extremely satisfied with the restorations. No all-ceramic crowns fractured during the observation period. One implant was lost after 5½ years in service. There were no significant differences for changes in any of the soft tissue registrations or the peri-implant marginal bone level between the conventional two-piece abutment-crown restoration and the one-piece restoration. The peri-implant bone level changes from placement to the clinical examination 10-11 years later were small (mean 0.26 mm, SD 0.6 mm). CONCLUSIONS: Zirconia abutments for single-implant crowns demonstrated excellent technical and biological results over 10-11 years of function, and most patients were extremely satisfied with the aesthetics and the function of their single-implant restorations.

Clinical performance of enamel-dentine bonded all-ceramic restorations: retrospective evaluation in a postgraduate clinic.

The aim of this retrospective study was to evaluate the clinical survival and success of five dif- ferent types of adhesive bonded all-ceramic restorations, in a postgraduate clinic. All ceramic enamel-dentin adhesive bonded restorations, either partial (n=94) or full coverage (n=145), were assessed by clinical examination using a modified Californian Dental Association (CDA) system for quality evaluation of dental care and a questionnaire assessing patient satis- faction (VAS) of 29 subjects with 239 restorations. The same 3-step adhesive bonding system in combination with dual-cured resin composite cement was used for all restorations Rubber dam was used for moisture control.The ceramics were evaluated with respect to patient satisfaction, esthetics, technical and biological complications. The reasons for treatment were mineralisation disorders (n=82), trauma (n=40), esthetic (n=57) and pathological tooth wear (n=60). Observation period for the restorations was up to 71 month (mean 33). All restorations were in place at the examinations (l00% survival rate). Number offractures and infractions were 28 and 20 respectively giving a 69% success rate. No significant difference was observed between full coverage and partial coverage restorations. Most of the fractures were small chippings of the veneering porcelain. From a biological point of view subgingival location of the restoration margin showed a significant correlation with bleeding on probing.The esthetic outcome seemed to depend on the ability of the selected veneering material to mask a severe tooth discoloration.The patients reported a high degree of satisfaction with both the esthetics and the function of their restorations. In conclusion all-ceramic enamel-dentin-bonded restorations demonstrated good short-term survival rate.The success rate was found to be lower. Both technical and biological complica- tions were present but mainly without any need of correction.The patients were in general very satisfied with the result of their dental treatment both esthetically and functionally.

Effect of chemical and mechanical debridement techniques on bacterial re-growth on rough titanium surfaces: an in vitro study.

OBJECTIVE: The aim of this in vitro study was to compare the effect of combined chemical and mechanical debridement of titanium (Ti) surfaces inoculated with Staphylococcus epidermidis, compared with the effect of chemical debridement alone. MATERIAL AND METHODS: Different Ti surfaces were characterized with respect to roughness and subsequently inoculated with S. epidermidis. NaCl (0.9 vol.%), EDTA (12 vol.%), H2O2 (3 vol.%) or H2O2 + TiO2 nanoparticles served as chemical debridement agents, while TiBrush was used as the mechanical debridement tool. Safranin staining assessed biomass still attached to surfaces after debridement. Biofilm viability was assessed after re-incubation of the debrided samples. SEM analysis was performed before and after the cleaning process. RESULTS: Surface average roughness (Sa ) of the samples was measured at 2.22 ± 0.19 µm for group A, 0.19 ± 0.02 µm for group B, and 1.99 ± 0.10 µm for group C. When chemical debridement agents were used alone, H2O2-containing products were most efficient in reducing the biomass load. The surface roughness did not affect the outcome of chemical debridement. However, when combining chemical and mechanical debridement, a further reduction of biofilm load and viability was observed with best effect on the smoothest surface. CONCLUSIONS: Combining H2O2-containing chemical agents with mechanical debridement (TiBrush) provided best reduction in biofilm mass and re-growth, when studied in vitro.

Chemical debridement of contaminated titanium surfaces: an in vitro study.

OBJECTIVE: To compare the efficacy of different chemical solutions when used for chemical debridement of biofilm contaminated titanium surfaces in an in-vitro experimental study. MATERIALS AND METHODS: Commercially pure titanium discs with a diameter of 6.2 mm and height of 2 mm, mirror-polished with a measured surface amplitude value SA = 0.037 µm ± 0.009 were used as test-surfaces. A biofilm was simulated with multi-layers of Staphylococcus epidermidis ATCC359844 covering the entire titanium surface. The chemical agents tested were: 3% H2O2, 0.2% Chlorhexidine, 24% EDTA-gel, 3% H2O2 mixed with 1.6 g/L TiO2 and sterile saline solution. The decontamination effect was evaluated by optical density analysis using spectrophotometry and with scanning electron microscopy (SEM) images of the remaining biofilm. RESULTS: The suspensions of 3% H2O2 and 1.6 g/L TiO2 or 3% H2O2 alone were the most effective in removing S. epidermidis biofilms (p < 0.05), whereas 0.2% chlorhexidine or 24% EDTA gel had no significant effects. SEM images of the remaining biofilms supported the quantitative results indicating the higher efficacy of 3% H2O2 and 1.6 g/L TiO2 or 3% H2O2 alone. It also revealed that EDTA, despite a non-significant effect on reducing the amount of established biofilms, was able to alter the biofilm architecture, as demonstrated by increased interspaced regions. CONCLUSIONS: In this in vitro study the decontamination potential of a suspension of 3% H2O2 and 1.6 g/L TiO2 or 3% H2O2 alone were encouraging. Whether such procedures would have a similar effect in vivo remains to be determined.

A replica technique for studying the effect of fluoride solutions on enamel erosion.

UNLABELLED: The aim of this in vitro study was to develop a replica technique aimed at reproducing an enamel surface exposed to erosive challenge. The replica technique was then used to compare the effect of treating enamel with different fluoride (F) solutions using an in vitro erosion model. Human molar teeth were split in two (total n=34 specimens), and half of each specimen was isolated with impression material. Part I: 10 specimens were exposed to either 0.18% or 1.8% citric acid, the impression material was removed and replicas were prepared. All specimens and replica models were analysed by profilometry and SEM. Part II: 24 specimens were treated with native 0.1 mol/L F-solutions (HF, SnF2, NaF and TiF4), the impression material was removed, and the specimens were then exposed to 1.8% citric acid. Replicas were prepared and analysed by profilometry and SEM. The median height difference between the F-treated areas and the non-treated areas for each F-solution was measured. SEM micrographs were analysed qualitatively blind bytwo of the authors. RESULTS: Part I--Replicas showed good topographical reproduction of the tooth specimens. Part II--HF had a significantly greater erosion-inhibiting effect than the other fluoride solutions at 0.1 mol/L F as shown by profilometry. SEM revealed a clearly defined border between F-treated and non-treated surfaces only for specimens treated with HF- and TiF solutions. In conclusion, the present replica technique was able to differentiate between the effect of treating enamel with different fluorides against dental erosion in vitro. The technique should be tested further for possible use in situ and in vivo.

Zirconia abutments for single-tooth implant restorations: a retrospective and clinical follow-up study.

OBJECTIVE: To evaluate the clinical outcome of custom-made zirconia abutments for implant-supported single-tooth restorations up to 5 years after insertion. MATERIAL AND METHODS: The study comprises two parts: (Part 1) retrospective evaluation of records of 130 patients treated with 185 single-tooth implant restorations using zirconia abutments; (Part 2) clinical examination of 25 patients with 40 restorations placed >3 years ago. Oral surgeons placed the implants. The prosthodontic treatment was provided at a prosthodontic specialist clinic. The restoration was either an all-ceramic crown for cementation or a screw-retained one-piece restoration with the veneering porcelain baked directly to the zirconia abutment. Registration of all patients' records comprised clinical and radiographic data from insertion of the restoration up to the last visit at the clinic. RESULTS: Parts 1 and 2: The zirconia abutments performed well over the follow-up period. The rates of both technical and biological complications were low, and the patients were in general extremely satisfied with the restorations. No all-ceramic crowns fractured during the observation period. Two abutments (1%) fractured, one at insertion, the other after 2 months. Part 2: There were no significant differences for changes in any of the soft tissue registrations or the peri-implant marginal bone level between the conventional two-piece abutment-crown restoration and the one-piece restoration. The peri-implant bone level changes from placement to the clinical examination 3-5 years later were small (mean 0.29 mm, SD 0.87 mm). CONCLUSION: Zirconia abutments for single-implant crowns seem to demonstrate good short-term technical and biological results.

Prosthodontic treatment of patients with disabilities at dental specialist clinics in the County of Västra Götaland.

In 1998 the Swedish Parliament decided about increased financing of dental support and service given to persons with disabilities who were dependent on nursing personnel or others in their activities of daily life including oral hygiene procedures. One part of the legislation called "Necessary dental care, group 3" (NDC3) includes persons with intellectual disabilities and disabilities due to brain damage, autism and autism-like disorders, and persons with lasting mental and physical disabilities not related to normal ageing. The objectives where to investigate persons affected by this legislation; how many and what patients covered by NDC3 in Västra Götaland County received prosthodontic therapy from 2001 through 2004, at hospital dental clinics or dental specialist clinics. Patients treated with prosthodontic restorations covered financially by the county council under the terms of NDC3 were identified through the county council's registers. The application forms for NDC3 were retrieved and information about patient characteristics and type of treatments were compiled. It was shown that 57 patients covered by NDC3 in Västra Götaland County received prosthodontic therapy at dental specialist clinics and 50 were treated at the hospital dental clinics for extensive prosthodontic treatment needs. The mean age for the patients rehabilitated with removable dentures was higher (56.2 years) compared with patients treated with single tooth implants (39.7 years). About 30 patients, representing 1 to 2% of the NDC3 population in Västra Götaland County were rehabilitated with more advanced prosthodontic restorations in hospital dental clinics or dental specialist clinics each year. In conclusion and with respect to the probably large need for prosthodontic therapy among persons with disabilities, the use of NDC3 has not been properly utilized.

Infraposition of anterior maxillary implant-supported single-tooth restorations in adolescent and adult patients-A prospective follow-up study up to 6 years.

BACKGROUND: In the maxillary incisor area infraposition of implant restorations can be an esthetic problem. PURPOSE: The aim was to analyze the prevalence of infraposition of single-tooth implant restorations in the anterior maxilla in adolescent and adult patients. MATERIAL AND METHODS: The study comprised of 31 patients, 18 women and 13 men, with 39 restorations and with a mean and median age of 23.8 and 18.8 years, range 17.8 to 52.8 years, at the time of implant crown connection. The mean and median time in function for the restorations was 4.5 and 4.3 years respectively with a range of 3.3 to 6.6 years. RESULTS: Twenty restorations 51%, showed no signs of infraposition. A slight infraposition (<0.5 mm) was seen in 36% of the restorations. Only in one patient, the observed infraposition of the implant crown was more than 1 mm. We found no significant difference of the observed level of vertical infraposition, Score A (0 mm) and Score B (<0.5 mm), in subjects where the restoration was placed before the age of 20 years compared to the older patients. There were no significant differences in changes of the vertical infraposition when comparing different parameters such as age, gender, jaw relation (Angle-classes I-III), overbite/overjet, occlusal contact on the implant crown, bone augmentation before or at implant installation or if orthodontic treatment of the neighboring teeth had been made before or after the implant installation. CONCLUSIONS: In the present study, there was a significant yet low correlation between the observed vertical infraposition of the single-tooth implant restoration and the subject's evaluation of the esthetics of the restoration (VAS). Fifty-one percent of the implant-supported crowns, showed no signs of vertical infraposition. A slight infraposition (< 0.5 mm) was however seen in 36% of the restorations. Only one crown showed a vertical infraposition of more than 1 mm.

Dental status and oral function in an adult group of subjects with thalidomide embryopathy - a clinical and questionnaire study.

OBJECTIVE: The purpose of the study was to present the results of an oral examination of individuals with thalidomide embryopathy in relation to dental conditions and functional aspects of the masticatory system, with a special focus on tooth wear. MATERIAL AND METHODS: All 108 subjects with thalidomide embryopathy living in Sweden were invited to participate in a comprehensive investigation, and approximately one-third, 31 subjects (13 F and 18 M, aged 45-49 years), took part. The methods included a questionnaire and clinical and radiographic examinations. RESULTS: Most of the subjects had regular dental care, which they in general considered sufficient. All except one always brushed their teeth themselves. One subject had limited mouth opening (25 mm). There were no great deviations from normal anatomy and function of the masticatory system. Caries and periodontal conditions were also normal. Regurgitation was reported by 42% of the subjects. Tooth wear was more extensive than in comparable age groups. About a third of the subjects had Class III or edge-to-edge occlusion. CONCLUSIONS: In general, subjects with thalidomide embryopathy had no great deviations in dental conditions from people of the same age in the general population except for an increased rate of tooth wear and a higher prevalence of prenormal jaw relations. Tooth wear was related less to use of the teeth as tools and more to dental erosion associated, among other things, with a high rate of regurgitation.

One-piece internal zirconia abutments for single-tooth restorations on narrow and regular diameter implants: A 5-year prospective follow-up study.

BACKGROUND: Studies have reported an increased risk for fractures of zirconia abutments compared with titanium abutments. PURPOSE: The aim of this study was to evaluate single-tooth implant restorations with one-piece yttria-stabilized internal zirconia abutments on narrow and regular diameter implants up to 6 years after insertion. MATERIAL AND METHODS: This study comprises 52 consecutively treated patients, with a median age of 19 years. In total, 59 narrow (3.3 mm) and 10 regular (4.1 mm) diameter implants were installed. Sixty-five all-ceramic crowns were cemented on implant-supported one-piece internal zirconia abutments and 4 restorations were screw-retained. RESULTS: Thirty-five patients with 48 implant restorations participated in the final examination and another 14 patients with 16 implant restorations were possible to reach and could be interviewed. The implant survival was 100% but the survival rate for the implant-supported ceramic restorations was lower, 87.5%. Three crowns (4.7%) were remade for different reasons. Five restorations (7.8%) were remade due to fracture of the internal one-piece zirconia abutment. Four of these fractures occurred in 3.3 mm implant abutments. CONCLUSIONS: Narrow diameter implants offer an opportunity to restore small single-tooth edentulous gaps. For esthetical reasons the choice of an abutment in zirconia can be favorable, but at least with the used implant system, there seems to be an increased risk for fracture. Most patients were very satisfied with the esthetics and function of their implant restorations.

Clinical evaluation of CAD/CAM metal-ceramic posterior crowns fabricated from intraoral digital impressions.

PURPOSE: The aim of this in vivo study was to evaluate the accuracy of metal-ceramic crowns fabricated using computer-aided design/computer-assisted manufacturing (CAD/CAM) in conjunction with intraoral digital impressions. MATERIALS AND METHODS: Fifty patients in a general practice participated in the study. Patients were provided with crowns fabricated from digital impressions taken with an intraoral chairside scanner. Prior to crown insertion, the marginal integrity, esthetics, and occlusal and articulation contacts were evaluated using California Dental Association (CDA) criteria. The precementation space of the crowns was evaluated with the replica technique. RESULTS: No adjustments were needed for any of the interproximal contact points. Adjustments of occlusion and articulation contacts were needed in 20% of the restorations. Clinical evaluation of the marginal integrity showed satisfactory results according to the CDA criteria. The 50 silicone replicas showed a median precementation space of 46 µm at the marginal measurement location, 94 µm at the midaxial location, and 185 µm at the centro-occlusal location. CONCLUSIONS: The precementation spaces of the crowns were within the acceptable range for CAD/CAM restorations.

Treatment with implant-supported fixed dental prostheses in patients with congenital and acquired neurologic disabilities: a prospective study.

PURPOSE: To study the medium- to long-term outcome of implant treatment in patients with neurologic disabilities. MATERIALS AND METHODS: Twenty-seven patients with different disabilities and in need of prosthodontic treatment were treated with various implant-supported prostheses. Altogether, 88 threaded titanium implants were placed. General anesthesia was used in 21 patients and local anesthesia in 6 patients. Patients were recalled every 3 months by a dental hygienist and annually by a prosthodontist. RESULTS: Five of the original 27 patients died during the 5- to 10-year follow-up period (mean, 7.2 years), but the remaining 22 patients with 70 implants could be clinically examined at the final follow-up. Twelve implants (14%) were lost, 3 before loading and 9 after insertion of the implant-supported fixed prostheses. The cumulative survival rate for placed implants was 85.8% after 10 years. Perimucositis was diagnosed in 10 patients and for 14 of the 70 implants. Three of the 15 patients with measurable radiographs and 4 implants were diagnosed with peri-implantitis. Several prosthodontic complications occurred, from minor and easily correctable to severe and requiring retreatment. CONCLUSIONS: Patients with different neurologic disabilities present more problems during implant treatment and maintenance compared with healthy patients. Nevertheless, it was possible to carry out treatment, and outcomes were relatively favorable. The results indicate that implant treatment can be a valid option in oral rehabilitation of patients with neurologic disabilities.

Early experience of implant-supported prostheses in patients with neurologic disabilities.

PURPOSE: The purpose of this prospective study was to provide a preliminary report of implant treatment in patients with neurologic disabilities. MATERIALS AND METHODS: Patients had been referred to the National Orofacial Resource Centre with different disabilities, specifically neurologic disorders causing various orofacial dysfunction problems, and were suitable for prosthodontic treatment with implants. Patients were treated with single implant-supported crowns, fixed partial dentures, or complete implant-supported dentures. Implants used were threaded titanium cylinders placed under general or local anesthesia. All surgical complications in the healing period or at second-stage surgery were noted, as were all prosthodontic complications. RESULTS: Fourteen patients were treated with 35 implants. Three implants were lost before or at second-stage surgery, and two implants were lost after loading. These complications were observed in two patients. Implant failures and other complications were observed in two patients in the mandible because of dehiscence of the mucoperiosteal flap and infection. Some patients had developed finger or oral habits, such as excessive tongue movements, that were probably responsible for these complications. One of the patients with Down syndrome possibly had reduced resistance to infections. No major complications were observed for the other 12 patients treated. CONCLUSION: Strict adherence to a surgical protocol is needed for the management of patients with neurologic disabilities. It is important to inform the patient's caregiver about maintenance of good oral hygiene and the increased risk of complications caused by finger or oral habits.

Implant-supported fixed partial prostheses: a retrospective study.

PURPOSE: The purpose of this retrospective study was to present treatment outcome and patient reactions to rehabilitation with implant-supported fixed partial prostheses. MATERIALS AND METHODS: Eighty-three patients were consecutively treated with implant-supported fixed partial prostheses (Brånemark system) from 1986 to 1995. Seventy-six of these 83 patients were examined (66 maxillary and 31 mandibular prostheses). The mean observation time was 53.9 months. In total, 285 implants were placed. Eleven implants were lost before loading. The first 41 prostheses were removed and the implants examined regarding the criteria for "success" and tightness of the screw joints. Only one implant had lost integration. RESULTS: The survival rate before and after loading was 96%, which included implants placed in augmented bone. All prostheses were stable at the time of examination. In prostheses with cantilevers (98 implants), 12% of the gold screws and 17% of the abutment screws showed a "not acceptable" loosening, compared to none in the prostheses without cantilevers (17 implants). The difference was not statistically significant. The mean marginal bone loss was 0.4 mm for the first year after prosthesis insertion and less than 0.1 mm per year in the following years. The most frequent prosthesis design was one pontic supported by two implants. Prostheses made in gold acrylic and titanium acrylic had more complications and showed a higher need for repair than metal-ceramic restorations. Patients reacted very positively to the esthetic results and comfort with eating, and were overall satisfied with their prostheses. CONCLUSION: Implant-supported fixed partial prostheses seem to have a very good prognosis and are well-accepted by patients.

Stability of the screw joints in patients with implant-supported fixed prostheses in edentulous jaws: a 1-year follow-up study.

PURPOSE: The purpose of this follow-up study was to evaluate the stability of the screw joint in edentulous patients 1 year after treatment with implant-supported fixed prostheses (Brånemark system). MATERIALS AND METHODS: A total of 20 patients were included, 10 treated in the maxilla and 10 in the mandible. The fixed prostheses were removed approximately 1 year after insertion, and the stability of the screw joints was evaluated using a rating scale based upon the CDA quality evaluation criteria of dental care. RESULTS: All implant-supported fixed prostheses were recorded as stable before the prosthetic screws (gold screws) were unscrewed. "Unacceptable loosening" was observed in 4% of the prosthetic screws and in 29% of the abutment screws. CONCLUSION: In this study, only a few of the prosthetic screws showed unacceptable loosening after 1 year of function. The clinical relevance of the observed high occurrence of loose abutment screws could be questioned, as all fixed prostheses were initially recorded as stable.

Peri-implant mucosal level in patients treated with implant-supported fixed prostheses: a 1-year follow-up study.

PURPOSE: The purpose of this follow-up study was to quantify the change in the peri-implant mucosal level after treatment of edentulous patients with fixed prostheses on osseointegrated endosseous implants. MATERIALS AND METHODS: Twenty patients were included in the study: 10 were treated in the maxilla, and 10 were treated in the mandible. Both groups had fixed prostheses on osseointegrated Brånemark implants. Peri-implant mucosal level was measured with a calibrated probe after removal of the prostheses at the 1-year follow-up. These measurements were compared to those made on the original master casts. RESULTS: A larger mean retraction (-) was observed in the mandible (-1.6 mm) compared to the maxilla (-0.8 mm), but there was great variation. The individual values varied from -4.5 to +1.0 mm in the mandible and from -6.0 to +6.0 mm in the maxilla. CONCLUSION: Peri-implant soft tissue recession occurs during the first year in edentulous jaws after treatment with implant-supported fixed prostheses and more so in the maxilla than the mandible.

Microbiological findings and host response in patients with peri-implantitis.

The aim of the present study was to characterise microbiota and inflammatory host response around implants and teeth in patients with peri-implantitis. We included 17 partly edentulous patients with a total of 98 implants, of which 45 showed marginal bone loss of more than three fixture threads after the first year of loading. Nineteen subjects with stable marginal tissue conditions served as controls. Oral hygiene, gingival inflammation, and probing pocket depth were evaluated clinically at teeth and implants. Microbiological and crevicular fluid samples were collected from five categories of sites: 1) implants with peri-implantitis (PI), 2) stable implants (SI) in patients with both stable and peri-implantitis implants, 3) control implants (CI) in patients with stable implants alone, 4) teeth in patients (TP) and 5) controls (TC). Crevicular fluid from teeth and implants was analysed for elastase activity, lactoferrin and IL-1 beta concentrations. Elastase activity was higher at PI than at CI in controls. Lactoferrin concentration was higher at PI than at SI in patients with peri-implantitis. Higher levels of both lactoferrin and elastase activity were found at PI than at teeth in patients. The concentrations of IL-1 beta were about the same in the various sites. Microbiological DNA-probe analysis revealed a putative periodontal microflora at teeth and implants in patients and controls. Patients with peri-implantitis harboured high levels of periodontal pathogens, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Bacteroides forsythus and Treponema denticola. These findings indicate a site-specific inflammation rather than a patient-associated specific host response.