Frequency of apical periodontitis in root-filled teeth restored with post and core: A 5-year retrospective study.

BACKGROUND: In conjunction with post placement in root-filled teeth with periapical healthy conditions, root canal retreatment may be performed to improve the seal of the root canal. Whether root canal retreatment for technical reasons (retreatments in teeth without apical periodontitis (AP)) results in lower frequency of AP is unknown. OBJECTIVE: To examine whether there is a difference in frequency of AP between roots with root canals retreated for technical reasons, and roots with root canals not retreated before post placement, with a minimum follow-up of 5 years. Also, to examine changes in root filling quality following root canal retreatment for technical reasons. METHODS: This retrospective study included radiographs of 441 root-filled roots without periapical radiolucencies at baseline, scheduled for post and core treatment. Follow-up data for a minimum of 5 years were available for 305 roots (loss to follow-up 30.8%), 46 of which were retreated for technical reasons. Two calibrated observers assessed root filling sealing quality and length, respectively, and periapical status according to the Periapical Index. The main outcome of the study, AP, was used as the dependent variable and all analyses were performed at root level. RESULTS: The overall frequency of AP at follow-up was 13.8%. The difference in frequency of AP between retreated (4.3%) and nonretreated (15.4%) root canals was not statistically significant, p = .061. Analyses including only roots with preoperatively inadequate root filling quality showed a statistically significant difference (p = .017) between the two treatment groups (2.4% vs. 22.9%). CONCLUSIONS: Root canal retreatment for technical reasons before post and core placement significantly reduces the frequency of AP in roots with inadequate root filling quality.

Chewing side preference and laterality in patients treated with unilateral posterior implant-supported fixed partial prostheses.

BACKGROUND: It is not clear to what extent chewing is improved by unilateral oral rehabilitation with implant-supported fixed partial prostheses (ISFPPs). OBJECTIVES: This study aimed to investigate whether patients treated with unilateral ISFPPs in the maxilla use their prostheses during mastication to the same extent as they used their contralateral natural teeth. A further aim was to investigate whether there is a correlation between preferred chewing side and laterality. METHODS: Chewing side preference was assessed in 15 participants treated with unilateral ISFPPs in the maxilla. The first, second, third, fifth and tenth chewing cycles were assessed, and the test was repeated 10 times. All participants also answered a questionnaire about their chewing side preference. RESULTS: Most of the participants presented bilateral chewing, but two (13%) chewed only on the ISFPP. There was no statistically significant association between the objectively assessed chewing side and dental status (natural teeth or ISFPPs) during any of the recorded chewing cycles (p > .1). There were statistically significant correlations between both the subjectively reported usually preferred chewing side and the subjective chewing side preference during the test and the objectively assessed chewing side for the first three chewing cycles (p < .01). No correlation was found between handedness and the objectively assessed chewing side. CONCLUSION: In the present study, most participants chewed bilaterally, and chewing was performed both on the ISFPP and on the natural teeth. No correlation was found between the preferred chewing side, objectively or subjectively determined and laterality.

Planned and unplanned follow-up visits after mandibular third molar surgery in the Public Dental Service in Örebro.

OBJECTIVE: This study examined the frequency of unplanned follow-up visits to the Public Dental Service in Örebro due to postoperative discomfort/complications after mandibular third molar surgery and associated factors. MATERIALS AND METHODS: Data were retrieved from the dental records of 465 patients who underwent mandibular third molar surgery in 2017. The collected data covered patient age and gender, health status, diagnosis, surgeon, and planned and unplanned follow-up visits. RESULTS: Twenty-eight percent of patients had unplanned visits after mandibular third molar surgery, while 68% of patients without a planned follow-up visit had an unscheduled visit. None of the patients with a planned visit had an unplanned visit. Female patients and patients who had bone removed during surgery had significantly more unplanned follow-up visits due to post-extraction discomfort (p=.047 and .01, respectively). Patients diagnosed with caries made fewer unplanned follow-up visits (p<.012). CONCLUSIONS: The frequency of unplanned follow-up visits after third molar surgery was relatively high, though no patient with a planned follow-up visit made an unplanned visit. Scheduling follow-up visits could significantly reduce the number of unplanned follow-up visits.

Fit of 3Y-TZP complete-arch implant-supported fixed dental prostheses before and after porcelain veneering.

STATEMENT OF PROBLEM: To minimize technical complications, implant-supported fixed dental prostheses must fit well. The fit of complete-arch veneered zirconia frameworks has not been fully evaluated. PURPOSE: The purpose of this in vitro study was to evaluate the fit of screw-retained zirconia implant-supported complete-arch maxillary frameworks for fixed dental prostheses before and after porcelain veneering. MATERIAL AND METHODS: Ten stone casts simulating an edentulous maxilla and provided with 6 abutment analogs were produced. For each stone cast, 1 zirconia framework was fabricated by computer-aided design and computer-aided manufacturing. The fit was analyzed by using a coordinate measuring machine in 3 dimensions (x, y, and z axes) using best fit by virtual matching of center point coordinates before and after porcelain veneering. Also, the horizontal distances between implant position pairs P1-P6, P2-P5, and P3-P4 were measured. Furthermore, an optical microscope was used to evaluate vertical fit at the terminal abutments after porcelain veneering. RESULTS: Before the porcelain veneering procedure, the frameworks had a mean horizontal misfit of 27.7 µm in the x-axis and 12.0 µm in the y-axis. In the vertical dimension (z-axis), the mean misfit was 2.4 µm and the mean 3D misfit value was 32.3 µm before veneering. Porcelain veneering increased the mean misfit by 0.2 µm in the horizontal plane (x and y axes), 0.4 µm in the vertical plane, and 0.4 µm in 3D; the difference before and after veneering was not statistically significant (P>.05). The mean ±standard deviation vertical misfit at the terminal abutments was 9.2 ±2.9 µm, optically recorded after porcelain veneering. The measured horizontal distances between implant position pairs P1-P6, P2-P5, and P3-P4 increased to 0.9 µm, 2.0 µm, and 1.9 µm, respectively, after porcelain veneering. The difference for the implant position pair P2-P5 was statistically significant (P<.05). CONCLUSIONS: Screw-retained zirconia implant-supported complete-arch maxillary frameworks for fixed dental prostheses have a fit well within the range of 30 µm in the horizontal plane and 10 µm in the vertical plane. The porcelain veneering procedure did not affect the fit of the frameworks.

Additively Manufactured Titanium and Cobalt-Chromium Implant Frameworks: Fit and Effect of Ceramic Veneering.

PURPOSE: The purpose of this study was to evaluate the fit of additively manufactured cobalt-chromium and titanium and CNC-milled titanium frameworks before and after ceramic veneering. MATERIALS AND METHODS: Ten stone casts simulating an edentulous maxilla provided with six abutment analogs were produced. For each stone cast, one additively manufactured cobalt-chromium framework (AM CoCr) and one titanium framework (AM Ti) were fabricated. The fit was analyzed with a coordinate measuring machine in three dimensions (x, y, and z axes) using best-fit virtual matching of center point coordinates, before and after ceramic veneering. CNC-milled titanium frameworks (CNC Ti) and earlier results from CNC-milled cobalt-chromium frameworks (CNC CoCr) were used for comparison. RESULTS: All frameworks presented minor misfit before and after veneering in the horizontal plane (x- and y-axes) between 2.9 and 13.5 µm and in the vertical plane (z-axis) between 1.6 and 5.4 µm. Ceramic veneering affected the fit of all groups of frameworks. Both AM Ti and AM CoCr presented significantly smaller distortion in the vertical plane compared with the CNC-milled frameworks. CONCLUSION: Implant-supported frameworks can be produced in either Ti or CoCr using either CNC milling or additive manufacturing with a fit well within the range of 20 µm in the horizontal plane and 10 µm in the vertical plane. The fit of frameworks of both materials and production techniques are affected by the ceramic veneering procedure to a small extent.

A retrospective multicenter study comparing metal-ceramic and composite single crowns performed in public general dentistry: 5-year results.

Objective The aim of this study was to evaluate and compare the 5-year survival and complication rate of metal-ceramic (MC) and composite single crowns performed within Public Dental Service, general dentistry, in three Swedish counties and with patients' gender, tooth position, root canal treatment and the presence of a post-and-core taken into account. Methods Data were collected from dental records of 600 patients who had received either an MC (n = 300) or a composite (n = 300) crown on a premolar or molar tooth in the year 2005 and where 5 years of follow-up data were available. Status at treatment completion and at follow-up was recorded, together with any history of intervention during the follow-up period. Results The 5-year survival rate for MC crowns was higher than for composite crowns (93% versus 70%; p < 0.001). This difference was stable, irrespective of the county, patients' gender or tooth position. No gender difference in survival rate was seen for MC crowns, while the survival of composite crowns was significantly higher among women than among men (75% versus 65%; p < 0.05). For MC crowns, there was a tendency toward a lower survival rate for endodontically treated teeth without a post-and-core (83%) as compared to those provided with a post-and-core (93%) and to vital teeth (94%). Surviving composite crowns had recordings of significantly more complications than MC crowns (p < 0.001). Conclusion On premolars and molars, MC crowns have a better medium-term prognosis and fewer complications than composite crowns.

Implant-Supported Single Crowns Replacing Congenitally Missing Maxillary Lateral Incisors: A 5-Year Follow-Up.

BACKGROUND: Knowledge of the long-term survival of single implants in cases of congenitally missing lateral incisors in the maxilla is limited. PURPOSE: This retrospective study aimed to evaluate the 5-year survival of implants and implant-supported crowns (ISCs) and to assess the functional and aesthetic outcomes from the professional and patient perspectives. MATERIALS AND METHODS: From a total of 46 patients with congenitally missing upper lateral incisors, 36 patients treated with 54 Brånemark® (Nobel Biocare AB, Göteborg, Sweden) implants and ISCs participated in the study. A clinical examination, California Dental Association (CDA) evaluation, and patient questionnaire were used to rate and compare the objective and subjective evaluations of the ISCs. RESULTS: The survival of implants and ISCs was 100%. The CDA ratings were satisfactory for all ISCs, with 70% being rated excellent. The patient rating was also high for the overall satisfaction item, with 21 being completely satisfied and 14 fairly satisfied. However, 12 patients wished for the replacement of their ISCs. Logistic regression analysis indicated that a less optimal embrasure fill was the most discriminating factor though not statistically significant (p = .082). CONCLUSIONS: One-third of the patients wished for the replacement of their ISCs. Soft tissue adaptation seems to be an important factor for overall satisfaction.

Fit of cobalt-chromium implant frameworks before and after ceramic veneering in comparison with CNC-milled titanium frameworks.

Computer-aided design/computer-aided manufacturing fabrication of implant-supported frameworks is a standard procedure, and the use of ceramic-veneered cobalt-chromium alloys is increasing. However, no data are available concerning the precision of fit of these frameworks and the impact on the fit of the veneering procedure. The aim of this study was to evaluate the fit of computer numeric-controlled-milled cobalt-chromium and titanium implant frameworks for edentulous maxillas, provided with six implants. An additional aim was to evaluate the effect of ceramic veneering on the fit of the cobalt-chromium frameworks. Ten stone casts simulating an edentulous maxilla provided with six dental implants and abutments were produced. One computer numeric-controlled-milled cobalt-chromium framework and one titanium framework were fabricated for each stone cast. Each stone cast and corresponding titanium and cobalt-chromium framework was measured with a coordinate measuring machine in the three-dimensional (X axis, Y axis, and Z axis) directions. Both milled titanium and cobalt-chromium frameworks presented a good fit in the vertical plane (Z axis), 5.3 µm for titanium frameworks and 4.6 µm for the cobalt-chromium frameworks. The titanium frameworks showed a statistically significant smaller mean degree of misfit in the horizontal plane, X (5.0 µm) and Y (2.8 µm) axes as compared with the cobalt-chromium frameworks presenting a mean deviation of 13.5 µm in X axis and 6.3 µm in Y axis (P < 0.001). After ceramic veneering of the cobalt-chromium frameworks, the horizontal distortion significantly decreased from 13.5 to 9.7 µm in X axis (P = 0.007) and from 6.3 to 4.4 µm in Y axis (P = 0.017). The fit of both titanium and cobalt-chromium frameworks was very good. There were small but significant differences in fit between the titanium and cobalt-chromium frameworks, but the difference is of no clinical significance. The ceramic veneering resulted in a minor but significant improvement of the fit for the cobalt-chromium frameworks.

Marginal and internal fit of cobalt-chromium fixed dental prostheses generated from digital and conventional impressions.

Objectives. Digital impressions are increasingly used and have the potential to avoid the problem of inaccurate impressions. Only a few studies to verify the accuracy of digital impressions have been performed. The purpose of this study was to compare the marginal and internal fit of 3-unit tooth supported fixed dental prostheses (FDPs) fabricated from digital and conventional impressions. Methods. Ten FDPs were produced from digital impressions using the iTero system and 10 FDPs were produced using vinyl polysiloxane (VPS) impression material. A triple-scan protocol and CAD software were used for measuring and calculating discrepancies of the FDPs at 3 standard areas: mean internal discrepancy, absolute marginal gap, and cervical area discrepancy. The Mann-Whitney U test was used for analyzing the results. Results. For conventional and digital impressions, respectively, FDPs had an absolute marginal gap of 147 µ m and 142 µ m, cervical area discrepancy of 69 µ m and 44 µ m, and mean internal discrepancy of 117 µ m and 93 µ m. The differences were statistically significant in the cervical and internal areas (P < 0.001). Significance. The results indicated that the digital impression technique is more exact and can generate 3-unit FDPs with a significantly closer fit compared to the VPS technique.

The accuracy of an implant impression technique using digitally coded healing abutments.

BACKGROUND: A healing abutment (Encode) provided with digitally coded information on length and diameter on the top was launched in 2007. So far, no study has evaluated working cast fabrication using impressions of the coded abutments and analogue placement using a robot technique. PURPOSE: To compare the accuracy of implant analogue placement in working casts using a robot technique and an impression of Encode healing abutments, with the traditional technique. MATERIALS AND METHODS: One acrylic master model was fabricated, provided with two groups of three implant analogues. Encode healing abutments were mounted on the test side and conventional pickup impression copings were inserted on the control side. Fifteen impressions were made with a vinylpolysiloxane material. Implant analogues were placed by a robot on the test side. The center point of each implant analogue fitting surface was measured with a laser measuring machine in the x-, y-, and z-axis, as were also the angular direction of the center axis and the position of the antirotational hex. Two-way analysis of variance was performed using SPSS 17.0; the statistical significance was set at p < .05. RESULTS: Mean center point deviation for the test and control side was 37.4 µm versus 18.5 µm (p = .001) in the x-axis, 47.3 µm versus 13.9 µm (p < .001) in the y-axis, and 35.0 µm versus 15.1 µm (p < .013) in the z-axis. Mean angle error was 0.41 degrees for the test and 0.14 degrees for the control side (p < .001). Mean rotation of the hexagon was 2.88 degrees for the test side and 1.82 degrees for controls (p < .001). CONCLUSIONS: Both conventional and robot technique presented low levels of displacement of the implant analogues in all casts. The test technique was less precise, but the difference in accuracy was small, and both techniques are precise enough for single crowns and short-span, implant-supported fixed partial prostheses.

A 5-year prospective clinical study of submerged and nonsubmerged Paragon system implants in the edentulous mandible.

PURPOSE: The aim of this investigation was to evaluate the clinical outcome of two different surgical protocols in the edentulous mandible: submerged and nonsubmerged. Further, the Paragon dental implant with a titanium plasma-sprayed surface was evaluated. MATERIALS AND METHODS: Twenty-nine consecutively treated patients with 168 implants supporting fixed prostheses were included. All but 3 patients were provided 6 implants, placed via nonsubmerged healing on one side and submerged healing on the other. Data were collected from patient records and radiographs. Twenty-four patients participated in the 5-year clinical follow-up examination. RESULTS: After 5 years, all patients still had their mandibular fixed prostheses in function. Cumulative survival rates were 100% for prostheses and 99.4% for implants. However, 3 implants fractured in 1 patient. One submerged implant was lost before loading but no further implants were lost during follow-up. The radiographic bone loss was small for all implants with a mean of 0.14 mm (standard deviation [SD]: 0.37) at 1 year and 0.42 mm (SD: 0.48) at 5 years for nonsubmerged implants and 0.17 mm (SD: 0.32) at 1 year and 0.51 mm (SD: 0.33) at 5 years for submerged implants. Nineteen implants (including the 3 that fractured) presented annual bone loss exceeding 0.2 mm after the first year, yielding a cumulative success rate of 86.2% after 5 years. CONCLUSION: Single-stage surgery was shown to have the same predictability as two-stage surgery in the anterior edentulous mandible. Paragon implants with a titanium plasma-sprayed surface showed a fracture rate of 2.2% and a success rate of 86.2% after 5 years.

The precision of fit of milled titanium implant frameworks (I-Bridge) in the edentulous jaw.

BACKGROUND: New computer numeric controlled (CNC)-milled frameworks for implant-supported prostheses have been introduced. However, no data are available on the precision of fit of these new frameworks. PURPOSE: The purpose of this study is to evaluate the precision of fit of a new CNC-milled framework technique (I-Bridge, Biomain AB, Helsingborg, Sweden) using Brånemark System (Nobel Biocare AB, Göteborg, Sweden) and NobelReplace (Nobel Biocare AB) system implants. MATERIALS AND METHODS: Ten test frameworks were fabricated for one master model for each implant system. Five additional frameworks were fabricated for five different models simulating clinical cases as controls (Brånemark System). The distortion of implant center point positions was measured in x-, y-, and z-axes and in three dimensions by using a contact-type coordinate measuring machine and a computer program developed specifically for this purpose. Mann-Whitney U-test was used to compare differences of distortion within and between the groups. RESULTS: The maximal distortion in arch width (x-axis) and curvature (y-axis) was within 71 and 55 microm for all frameworks, respectively. The mean distortion in absolute figures in x-, y-, z-axes and three dimensions was for "clinical control" frameworks 23, 26, 4, and 34 microm as compared with less than 12, 12, 2, and 17 microm for Brånemark and NobelReplace frameworks, respectively. Control frameworks showed significantly (p < .05) greater mean and range of distortions in x- and y-axes and in three dimensions compared with test frameworks. CONCLUSION: All measured frameworks presented signs of misfit, indicating that no framework had a "passive fit." Frameworks produced in a more routine clinical environment seem to present greater levels of distortion as compared with frameworks produced in a strict test situation. However, all measured frameworks presented levels of precision of fit within limits considered to be clinically acceptable in earlier studies of frameworks placed on abutments.

A retrospective analysis of early and delayed loading of full-arch mandibular prostheses using three different implant systems: clinical results with up to 5 years of loading.

BACKGROUND: Early loading of implant-supported prostheses in the edentulous mandible is widely accepted, but do the clinical results replicate those of delayed loading? PURPOSE: The aim of this study was to evaluate clinical outcome and patient satisfaction with early or delayed loading in patients treated with fixed prostheses, using three different implant systems. MATERIALS AND METHODS: One hundred and nine consecutively treated patients received 490 implants supporting fixed prostheses; 82 patients with Brånemark System implants (Nobel Biocare AB, Göteborg, Sweden), 16 with Astra Tech implants (Astra Tech AB Dental Implant system, Mölndal, Sweden), and 11 with ITI MonoType implants (ITI Dental Implant System, Institute Straumann AG, Waldenburg, Switzerland). Prostheses were placed within 2 to 3 weeks in 55 patients; 54 patients underwent a two-stage procedure. Data were collected from patient records and radiographs; 83 patients attended a clinical examination and received a questionnaire. RESULTS: All patients had fixed prostheses at follow-up with a mean observation time of 3.5 years. Cumulative survival rates (CSRs) were 92.5% of prostheses and 94.4% of implants for early loading, and 98.0 and 97.9% for delayed loading. The mean radiographic bone loss after the first year was small, and at 5 years less than 0.2 mm for both groups. With early loading, significantly more prostheses (p < .05) needed adjustment or replacement. CONCLUSION: Statistically significantly more prostheses needed adjustment or replacement in the early group. The present study suggested lower CSRs for prostheses and implants in the early loading group after 5 years; the difference was not statistically significant. Larger study samples are needed to verify statistically small differences between treatment techniques.

On the role of number of fixtures, surgical technique and timing of loading.

AIMS: The aims of this thesis were to analyze reduced number of implants supporting full arch fixed mandibular prostheses and fixed partial dentures (FPDs), non-submerged healing and early loading in the edentulous mandible. A further aim was to evaluate fit of Computer Numerical Controlled (CNC) milled I-Bridge frameworks. MATERIAL & METHODS: Paper I. One hundred and nineteen patients rehabilitated with full arch mandibular prostheses supported by four implants were evaluated after a mean follow-up of 4.4 years. Paper II. A total of 178 patients provided with FPDs supported by two (n=92) or three implants (n=122) of whom 123 were evaluated after a mean follow-up of 9.4 years. Paper III. Early and delayed loading of full arch mandibular prostheses were evaluated in 109 patients, 54 with delayed loading and 55 with early loading, with a mean follow-up of 3.6 years. Paper IV. Submerged and non-submerged implant placement for supporting fixed prostheses in the edentulous mandible were evaluated after five years in 29 patients. Paper V. The precision of fit of CNC-milled I-Bridge frameworks was evaluated using two different implant systems. RESULTS: Paper I. The five-year cumulative survival rate (CSR) for implants was 99.1% and for prostheses 100%. Mean bone loss from baseline to five-year follow-up was 0.5 mm. No indication could be found that the number of supporting implants influenced the prosthetic complications. Paper II. The five-year implant and prosthesis CSR was 97.7% for two-implant supported FPDs and 97.3% for three-implant supported FPDs. Mean bone loss at five years was 0.4 mm. Significantly more prosthetic and abutment screw loosening were seen in two-implant supported FPDs. Paper III. Five-year CSR for implants was 94.4% and 92.5% for prostheses in early loading, and 97.9% and 98.0% in the delayed loading group. More prostheses needed adjustment or replacement in the early group, but patients treated with early loading were more pleased with the treatment procedure. Paper IV. Five-year CSR survival rate was 99.4%. Three implants fractured in one patient. Mean bone loss at five years was 0.7 mm in submerged implants and 0.5 mm in non-submerged implants. Paper V. All frameworks demonstrated clinically acceptable fit with mean distortion values within 23 microm (x-axis), 26 microm (y), 4 microm (z- axis) and 34 microm (3-D) for all frameworks. Control frameworks displayed greater levels of distortion than frameworks produced in a strict test situation. CONCLUSION: A reduction of the number of supporting implants to four implants in full arch mandibular prostheses and two implants in three unit FPDs in partial edentulous jaws resulted in the same clinical outcome as when more implants are used. Non-submerged implant placement in the edentulous mandible was as predictable as submerged, but early loading of implant-supported mandibular prostheses incurred more prosthetic complications. Computer numerical controlled milled frameworks presented levels of precision of fit within limits considered to be clinically acceptable and superior to earlier published results on cast frameworks.

A clinical evaluation of cobalt-chromium metal-ceramic fixed partial dentures and crowns: A three- to seven-year retrospective study.

STATEMENT OF PROBLEM: In severely compromised dentition, loading of long-span and cantilever metal-ceramic fixed partial dentures (FPDs) could result in framework deformation and porcelain fractures. The use of cobalt-chromium (Co-Cr) alloys may be advantageous, but there is little information on the longevity of, and complications with, prostheses made with these alloys. PURPOSE: The aim of this retrospective study was to report the survival and complication rates of Co-Cr metal-ceramic FPDs and crowns followed over a 3- to 7-year period. MATERIAL AND METHODS: The study included 42 patients with a total of 51 FPDs and 12 single crowns assigned to 1 of 3 groups. The 3 groups comprised patients with abutment teeth with a questionable prognosis (n=10), advanced chronic periodontitis (n=19), or abutment teeth with a positive prognosis (n=13). The FPDs had a mean of 9.7 units (range of 3-14). Of the FPDs, 32 were provided with a cantilever on 1 side (n=24) or both sides (n=8). The mean observation time was 51 months (range of 28-82). All patients were examined by 2 independent prosthodontists using the California Dental Association (CDA) assessment system for evaluation. One-way ANOVA with Fisher's LSD post hoc test and the Mann-Whitney U test were used for statistical analyses (alpha=.05). RESULTS: Seventeen (34%) of the FPDs had biological and/or technical complications. Six (12%) FPDs were completely or partially removed during the observation period, 1 framework fractured, and 9 (17.6%) FPDs had ceramic fractures. Fifteen of the 21 fractured FPD units were related to FPDs that were placed in 3 patients with bruxing habits. The CDA rating for marginal integrity was "excellent" for more than 98% of the abutments. No patients reported adverse reactions to the material. CONCLUSIONS: Metal-ceramic FPDs made of cobalt-chromium alloy performed acceptably in the questionable prognosis and advanced chronic periodontitis groups.

Fixed partial prostheses supported by 2 or 3 implants: a retrospective study up to 18 years.

PURPOSE: The purpose of this study was to evaluate and compare the long-term performance of fixed partial prostheses supported by 2 or 3 implants. MATERIALS AND METHODS: All patients treated with fixed partial prostheses supported by either 2 or 3 implants during the period 1985 to 1998 were included in this retrospective report. Annual clinical follow-up examinations were performed, with special attention to stability of the prostheses and peri-implant and occlusal conditions. Radiographic examination was performed when the prostheses were delivered (year 0) and subsequently at 1-year, 5-year, and 10-year examinations. RESULTS: A total of 178 patients had received fixed partial prostheses (FPPs) during this period of whom 123 (77 women and 46 men) were available for follow-up (mean age = 65 years, range 32-91). These 123 patients received a total of 146 implant-supported FPPs (63 two-implant- and 83 three-implant-supported) supported by 375 implants. The mean observation periods for the 2- and 3-implant-supported restorations were 9.6 years and 9.4 years (range, 5 to 18 years), respectively. Survival rates for the 2- and 3-implant-supported prostheses were 96.8% and 97.6%, respectively. The implant survival rate after loading was 98.4% for both groups. The mean bone loss at the 5-year follow-up was 0.3 mm for the 2 groups. No significant differences in bone loss (P > .05), implant failure rate (P > .05), or incidence of mechanical complications (P > .05) were found between the 2 prosthesis designs. The complications differed, significantly, with more loose gold and abutment screws in the 2-implant-supported group (P < .05) and more porcelain fractures in the 3-implant-supported group (P < .05). CONCLUSION: The 2-implant-supported partial prostheses exhibited long-term clinical performance comparable to prostheses supported by 3 implants.

20-year follow-up of patients receiving high-cost dental care within the Swedish Dental Insurance System: 1977-1978 to 1998-2000.

The objective was to perform a long-term follow-up study of patients that had received high cost dental care within the Swedish National Dental Insurance System in 1977-1978 with special focus on remaining teeth, periodontal disease progression, change in the prevalence of root-filled teeth and teeth with apical periodontitis as well as the survival of fixed prosthetic reconstructions. All 262 patients who had had their treatment plans sent for approval for high-cost dental care in 4 local health insurance districts and who were sampled for base-line studies in 1977-1978, were offered a free clinical examination including radiographs in 1998. 177 patients (68 % of the original sample) could be reached for telephone interview and 104 of them (40 % of the original sample) were examined clinically and radiographically. Comparisons were made with records and radiographs from 1977-1978. The analyses were performed with the individual patient as the studied unit. The low progression of severe periodontal disease during the 20-23 year follow-up period and the decrease in number of teeth with apical periodontitis among a majority of the patients examined, indicated that the dental care received resulted in a limitation of dental disease on the individual level. Furthermore 63 % of the patients had the fixed prosthetic reconstructions, received after approval 1977-1978, in full extention after 20-23 years. However, more tooth losses were observed among the patients in this study than in similar studies in Swedish general populations over the same decades. Furthermore multiple tooth extractions were significantly more frequent in patients with severe periodontitis at baseline and in patients with less apical periodontitis at follow-up in this study. Thus it seems that tooth extraction not seldom was a treatment choice for teeth with severe periodontitis and apical periodontitis among the patients examined clinically in this study.