A systematic review of single crowns on endodontically treated teeth

OBJECTIVES: To test the hypothesis that the placement of a crown is associated with improved (long term) survival of root canal treated teeth, using a systematic review process of clinical studies. DATA SOURCES: Papers referring to single crowns on endodontically treated teeth were located by a MEDLINE search and hand searching. One thousand six hundred and nine references were found, and they were subjected to a systematic review procedure. STUDY SELECTION: A three-step inclusion-exclusion procedure was applied to identify papers that represented; good scientific practice (GSP), reported results of all patients, restorations on root canal treated teeth (RCT) for more than 2 years and had sufficient data to generate life table analyses. The outcomes were 'survival of RCT restored with crowns' and 'survival of RCT with direct restorations'. Ten studies survived. These data showed an overall mean GSP of 0.605 with a 10-year survival of 81% for crowned RCT and a 10-year survival of 63% for RCT with direct restorations (resin composites, amalgam, cements). CONCLUSION: RCTs restored with crowns show an acceptable long-term survival of 10 years, while direct restorations have a satisfactory survival only for a short period.     

Single-tooth replacement with the Frialit-2 system: a retrospective clinical analysis of 146 implants

PURPOSE: This study was intended to provide a report of experience and results with Frialit-2 implants used for single-tooth replacement. MATERIALS AND METHODS: Over a 7-year period (1994-2000), 146 single-tooth implants (84 maxilla, 62 mandible) were placed in 112 patients (67 females, 45 males; 31.2 +/- 16.4 years). The sites included maxillary anterior teeth (n = 38) as well as the mandibular premolars and molars (n = 57). Ninety-three crowns were cemented and 53 crowns were screw mounted (22 with vertical, 31 with horizontal screws) on standard abutments. The follow-up time varied between 3 and 80 months (35.8 +/- 16.5 months). RESULTS: Two implants (1.4%) were lost, 1 during early loading and the other after 6 years. The most frequent prosthetic complication was isolated crown loosening of cemented crowns requiring recementation of 9 crowns (9.9%). Crowns with vertical screws showed no crown and/or screw loosening. Four crowns (2.8%) were replaced because of ceramic fracture. DISCUSSION: Peri-implant soft tissue condition, bone resorption, and Periotest values indicated satisfactory results. The cumulative implant survival rate during the follow-up period was 97.3%, and that of the crowns 96.4% (total cumulative survival rate 93.7%). CONCLUSIONS: With the low number of abutment screw loosenings (3.5%), the deep internal hexagonal retention compared favorably to external retention methods. The predominant use of long implants (98.4% > or = 13 mm) allowed a favorable implant/crown ratio with the potential for problem-free, long-term results.     

A retrospective evaluation of 1,387 single-tooth implants: a 6-year follow-up

BACKGROUND: The aim of this study was to evaluate the overall survival rate and factors that affect the clinical outcome of 1,387 consecutively placed implant-supported single restorations up to 6 years. METHODS: During 6 years (1999 to 2005), 1,387 implants were placed in 1,215 subjects (1,073 males and 142 females) who required single-tooth replacements. The average time from implant placement was 2.7 +/- 3.27 years. Implants were mostly placed in the maxillary premolar area (39.5%) followed by the anterior maxillary area (28.7%). Implant survival and location, need for bone augmentation, and implant dimensions were recorded and analyzed. RESULTS: Failed implants totaled 96, resulting in an overall survival rate of 93.1%. The vast majority of failures (94.8%) occurred during the first year following implant placement. Bone augmentation was performed in 9.7% of the implants with a 92.5% survival rate, similar to the survival rate of non-augmented areas (93.1%; P = 0.79). The average implant length was 13.3 mm, ranging from 8 to 16 mm. Longer implants (> or =11 mm) showed similar survival rates as implants <11 mm (93.2% versus 90.2%, respectively; P = 0.4). Implant width ranged between 3.25 to 5 mm (mean 3.9), with no effect on implant survival (P = 0.43). There was a significant difference in implant survival according to the anatomic zone of implant placement (P = 0.0075). The maxillary premolar area showed the highest survival rate (96.2%). CONCLUSION: Implant-supported single-tooth replacement is a predictable procedure with good survival rates up to 6 years.     

Multicenter retrospective analysis of the ITI implant system used for single-tooth replacements: results of loading for 2 or more years.

This report involves the retrospective evaluation of ITI implants placed by a group of 12 clinicians located throughout the United States. Of the original 174 single implants placed in 129 patients reported previously, 157 were examined in 110 patients after 2 or more years (average 40.1 months). Twenty-two implants remained in the anterior and 135 implants (86%) remained in the posterior areas of the mouth, with 81 being restored with an octabutment screw-retained crown and 76 restored with a conical-abutment cemented crown (in function 2 years or longer). Occlusal screw loosening was observed in 22.2% of implants over both periods, with only 1 tooth loosening in both study periods (6 months to 2 years and > or = 2 years). Loosening of a solid conical abutment occurred in 1 additional patient, for cumulative conical abutment loosening of 5.3%. Significant radiographic bone loss was observed around 4 implants, with implant fracture noted with 3 additional implants (all mandibular first molars with hollow-screw or hollow-cylinder implant design). The survival rate at > or = 2 years was 95.5%. The data suggest that ITI implants can be a satisfactory choice for posterior single-tooth restorations.     

Long-term survival and success of oral implants in the treatment of full and partial arches: a 7-year prospective study with the ITI dental implant system

PURPOSE: This study evaluated the long-term survival and success of different implant-supported prostheses supported by ITI implants. MATERIALS AND METHODS: Two hundred fifty consecutive patients were rehabilitated using implant-supported prostheses. Seven hundred fifty-nine implants were loaded. Single-tooth prostheses (n = 106), cantilever fixed partial prostheses (n = 42), fixed partial prostheses (n = 137), fixed complete prostheses (n = 5), implant/tooth-supported prostheses (n = 13), and overdentures (n = 37) were used. The mean follow-up period was 3.85 years. Life table analyses were performed. Implant survival rates were calculated by means of standard life table principles. Statistical analysis was performed to compare the implant survival and success by implant placement site for each type of prosthesis. RESULTS: The cumulative implant survival rates were calculated for implants supporting single-tooth prostheses (95.6%), cantilever fixed partial prostheses (94.4%), fixed partial prostheses (96.1%), fixed complete prostheses (100%), implant/tooth-connected prostheses (90.6%), and overdentures (95.7%). Similar survival and success rates were documented for implants placed in maxillae and mandibles. Implant size did not influence survival. DISCUSSION: Seven-year survival rates were similar for implants supporting single-tooth prostheses, cantilever fixed partial prostheses, fixed partial prostheses, and implant/tooth-supported prostheses. Medium-long term implant survival and success were not influenced by the site (maxilla or mandible). Implant and prosthetic survival rates for overdentures supported by 2 implants were comparable to those for overdentures supported by 3 or more implants. CONCLUSION: Prostheses supported by ITI implants represent a reliable medium-term treatment. (More than 50 references.)     

A multicenter 12-month evaluation of single-tooth implants restored 3 weeks after 1-stage surgery

The time-intensive, multi-step process of dental implant therapy limits patient acceptance. This 3-year prospective multicenter study sought to determine the safety of an expedited therapy that consisted of loading unsplinted maxillary anterior single-tooth implants 3 weeks after 1-stage surgical placement, and determination of the peri-implant cortical bone and mucosal responses to the expedited procedure. Fifty-two patients missing 1 or 2 maxilliary anterior teeth were enrolled in a study approved by the Institutional Committee on Human Subjects Research and based on strict inclusion and exclusion criteria. Astra Tech ST implants placed in a 1-stage procedure were restored 3 weeks later with ST abutments and a provisional crown (baseline); 7 to 9 weeks later, a porcelain-fused-to-metal or all-ceramic crown was cemented. Radiographic and clinical examinations were made at baseline and at 6 and 12 months. Implant survival was recorded. Cortical bone responses and peri-implant mucosal responses were evaluated. Fifty-eight implants were placed. During the 3-week period after implant placement, 4 patients were dismissed because of smoking cigarettes (a protocol deviation), and 1 patient was excluded because of deviation in loading time. Of the remaining 53 implants, 2 failed before definitive crown cementation. The resultant 96.2% survival rate was independent of implant length, tooth position, and bone quality/quantity. The mean change in marginal bone level was 0.4 mm at 12 months. The number of surfaces with plaque decreased from 3.4% at baseline to 0.5% at 12 months. The surfaces with inflammation also decreased. A mean gain in papilla length of 0.61 mm occurred, and a gain in buccal gingiva (x = 0.34 mm) was observed. A high success rate with positive tissue responses was achieved for maxillary anterior unsplinted single-tooth implants placed in a 1-stage surgery and restored at 3 weeks. This 2-component system is suited to a single-stage, rapid loading protocol for esthetic single-tooth replacement.     

Systematic review of 10 years of systematic reviews in prosthodontics

PURPOSE: The objective was to make an inventory of systematic reviews in the field of prosthodontics and to assess the strength of evidence yielded by these studies. MATERIALS AND METHODS: The literature was searched using MEDLINE (keywords "dental" in subset combined with "meta-analysis" in publication type, and "dental" in subset combined with "systematic review"). Reviews related to prosthodontics were selected by hand. Analogies between the reviewing processes were assessed, and the quality was described. RESULTS: There were 138 articles qualifying as either systematic reviews or meta-analyses. Of these, 13 reported pooled data on prosthodontic subjects. Two pairs of reviews were identified as dealing with comparable items; the others described all different subjects. In one pair, the studies reviewed the survival of conventional fixed partial dentures (FPD); the other pair was on single-tooth implants. The pooled results within each pair were almost equal. For the FPD reviews, 65% of the unity of studies was included in both reviews. For the single-tooth implants, 29% of the potentially useful studies were included in both reviews. The data pooling processes showed the same pattern. One large study included in both reviews explained a large part of the similarity of the combined survivals of FPDs. For the single-tooth implant reviews, the largest common study explained 20% of the similarity. CONCLUSION: Although there were methodologic differences between the paired reviews, they produced similar results. The outcomes of the evaluated reviews may be used as prognostic data; however, they cannot be used for direct comparison of treatments.     

Preliminary 3-dimensional surface texture measurement and early loading results with a microtextured implant surface

PURPOSE: This investigation was conducted to obtain preliminary roughness data on a microtextured implant surface and to determine its ability to sustain a 1-stage surgical procedure and early full occlusal loading of single-tooth restorations in humans. MATERIALS AND METHODS: Three-dimensional (3D) vertical scanning interferometry was conducted on samples of the test surface (MTX) and 2 control surfaces (Osseotite and sandblasted/acid-etched [SLA]). Test implants were also placed in vivo, restored with fully occluding single-tooth restorations (n = 27) after 2 months of nonsubmerged healing, and clinically monitored for 48 months of follow-up. RESULTS: Microtexture was relatively uniform on the test surface and more random and irregular on the control surfaces. MTX and Osseotite were similar in some roughness parameters, but the MTX surface had a greater number of micropits that were spaced closer together (Stylus Y lambda q) and with higher slope values (Stylus Y delta q). Cumulative life table results were 100% for all MTX implants placed in maxillary and mandibular jaw locations, and no discernible marginal bone changes were observed. Overall implant success was 100% after 4 years of clinical functioning. DISCUSSION: The findings of this study appear promising but should be considered preliminary, because of the limitations in the number of locations measured on each product sample and the small number of implants clinically studied. CONCLUSION: Within the scope of the present study, MTX implants exhibited a uniform micropitted surface, as well as 100% survival and 100% clinical success after nonsubmerged placement, early loading with single-tooth restorations at 2 months, and 48 months of clinical functioning. (More than 50 references.)     

Incidence of endodontic implantitis and implant endodontitis occurring with single-tooth implants: a retrospective study

The purposes of this study were to determine success and survival rates for implants and teeth adjacent to implants and the incidence of endodontic implantitis (E-I) (endodontic involvement in adjacent teeth causing implant failure) and implant endodontitis (I-E) (implant placement causing endodontic failure). The data were from 233 single-tooth implants placed in 116 subjects by postgraduate periodontal students with recall radiographs taken >or=9 months after implant placement. Three groups were analyzed: group A, implants with no adjacent teeth (n = 90); group B, implants with nonendodontically treated adjacent teeth (n = 123); and group C, implants with endodontically treated adjacent teeth (n = 20). The success and survival rates for implants were both 92.2% in group A, 98.4% and 99.2% for group B, and 85% and 95% for group C, respectively. For adjacent teeth, they were both 99.4% in group B compared with 75% and 90% in group C. However, after case review, none of the implants or adjacent teeth in group B were considered to have E-I or I-E, and one (5%) of the implants in group C had E-I and two (10%) of the adjacent teeth may have had I-E. The results of the present study agree with previous research, which suggests that endodontically treated teeth adjacent to single-tooth implants are usually successful and should be maintained.     

A Systematic Review of the Clinical Performance of Tooth‐Retained and Implant‐Retained Double Crown Prostheses with a Follow‐Up of ≥3 Years

Purpose: The objective of this review was to systematically screen the literature for data related to the survival and complication rates observed with dental or implant double crown abutments and removable prostheses under functional loading for at least 3 years. Materials and Methods: A systematic review of the dental literature from January 1966 to December 2009 was performed in electronic databases (PubMed and Embase) as well as by an extensive hand search to investigate the clinical outcomes of double crown reconstructions. Results: From the total of 2412 titles retrieved from the search, 65 were selected for full‐text review. Subsequently, 17 papers were included for data extraction. An estimation of the cumulative survival and complication rates was not feasible due to the lack of detailed information. Tooth survival rates for telescopic abutment teeth ranged from 82.5% to 96.5% after an observation period of 3.4 to 6 years, and for tooth‐supported double crown retained dentures from 66.7% to 98.6% after an observation period of 6 to 10 years. The survival rates of implants were between 97.9% and 100% and for telescopic‐retained removable dental prostheses with two mandibular implants, 100% after 3.0 and 10.4 years. The major biological complications affecting the tooth abutments were gingival inflammation, periodontal disease, and caries. The most frequent technical complications were loss of cementation and loss of facings. Conclusions: The main findings of this review are: (I) double crown tooth abutments and dentures demonstrated a wide range of survival rates. (II) Implant‐supported mandibular overdentures demonstrated a favorable long‐term prognosis. (III) A greater need for prosthetic maintenance is required for both tooth‐supported and implant‐supported reconstructions. (IV) Future areas of research would involve designing appropriate longitudinal studies for comparisons of survival and complication rates of different reconstruction designs.     

Implant-supported single-tooth restorations: a 5-year prospective study

BACKGROUND: Comparatively few studies are available reporting at least 5 years of follow-up data of implant-supported single-tooth replacements. OBJECTIVE: To evaluate prospectively the 5-year outcome of implant-supported single-tooth prosthetic restorations. MATERIAL AND METHODS: Forty subjects (mean age 41 years), 23 males and 17 females, who required single-tooth prosthetic replacement for a missing tooth were recruited. A total of 45 self-tapping implants (Astra Tech ST-implants)--40 in the maxilla and five in the mandible--were installed in a two-stage procedure. Abutment connection was performed 3-6 months after implant installation. Clinical and radiographic examinations were performed at the completion of the prosthetic treatment and once a year during a 5-year follow-up period. The analysis of peri-implant bone level alteration was performed on subject and implant levels and by the use of analysis of variance and binary logistic regression. RESULTS: Three patients were lost during the 5 years of follow-up. One implant was lost after 2.5 years in function and another four implants could not be accounted for at the 5-year follow-up examination. The overall failure rate at 5 years was 2.6% (subject level) and 2.3% (implant level). The mean loss of marginal bone at the implants during the first year in function was 0.06 mm (SD 0.67) on the subject level and 0.02 mm (0.65) on the implant level. During the subsequent 4 years the annual change in peri-implant bone level amounted to -0.02 mm (0.22) on both subject and implant levels. Thus, the mean total bone level change over the 5-year interval was -0.14 mm (1.04) on subject level and -0.11 mm (1.00) on the implant level of analysis (p>0.05). The frequency of implants with a 5-year bone loss of > or =1 mm was 13%. Approximately 50% of the implants demonstrated no bone loss. CONCLUSION: The present clinical trial on single-tooth replacements with the Astra Tech implant system demonstrated that the bone loss during the first year of function as well as annually thereafter was small.     

The single-tooth implant: a viable alternative for single-tooth replacement

BACKGROUND: The use of dental implants for single-tooth replacement cases introduces a challenge to the performance of these restorations. Clinical data suggest that single-tooth implant restorations do not benefit from lateral support from the surrounding dentition as do bridged implants, and that these restorations are subjected to greater masticatory forces. Therefore, single-tooth implants are exposed to an increased risk of failure. This prospective clinical trial was designed to evaluate the cumulative success rate of dual acid-etched single-tooth replacement implants in two clinical centers. METHODS: The study protocol included 59 patients between 19 and 73 years. Implants were evaluated for mobility, infection, and crestal bone loss from 30.9 to 60 months. RESULTS: Seventy-one (71) implants were placed in 59 patients, 20 male and 39 female. Forty-seven (47) were placed in the maxilla and 24 in the mandible. The percentages of anterior and posterior implants were 45.1% and 54.9%, respectively. A total of 13 (18.4%) implants were placed in soft, poor quality (Type IV) bone. Beginning 1 month post-implant placement, cases were followed for 30.9 to 60 months with a mean follow-up of 45.9 months. One implant failed (peri-implant infection) yielding an overall success rate of 98.6%. CONCLUSIONS: This success rate for single-tooth replacement dual acid-etched implants compares favorably with bridged implants and with success rates of other single-tooth implant studies. Dual acid-etched implants performed well even under conditions of poor quality bone, where concomitant bone augmentation was performed, and when used for immediate replacement of extracted teeth.     

Immediate loading of single-tooth implants: immediate versus non-immediate implantation. A clinical report

The hypothesis of the present study was that immediate loading of implant-supported restorations replacing single missing teeth could be a successful procedure. The present study compared the clinical success of immediately loaded single-tooth implants placed in fresh extraction sites to that of immediately loaded single-tooth implants placed in healed sites. From the years 1997 to 1998, 26 patients, ranging in age from 18 to 70 years, presented for the placement of 28 immediately loaded implants intended to support single-tooth ceramometal restorations. Nineteen implants were placed into fresh extraction sites, and 9 implants were placed into healed sites. Temporary prefabricated acrylic resin crowns were prepared and adjusted. At the time of traditional second-stage surgery (3 to 6 months after implantation), the implants were restored with single-tooth ceramometal prostheses. The survival rates were 82.4% and 100% for immediate and non-immediate implants, respectively. Follow-up ranged from 6 to 24 months from the day of implant placement, with a mean of 13 months for the immediate implants and 16.4 months for the non-immediate implants. Radiographic marginal bone loss after 3 to 6 months did not extend beyond the abutment-implant junction. Within the limits of the present investigation, immediate loading of single-tooth implants placed in healed sites is a possible treatment alternative. Immediate loading of single-tooth implants placed in fresh extraction sites carried a risk of failure approximating 20% in this patient population.     

Maxillary sinus lift for single implant-supported restorations: a clinical study

PURPOSE: The aim of this study was to evaluate single-tooth implant-supported restorations placed in conjunction with several methods of maxillary sinus augmentation. MATERIALS AND METHODS: A retrospective review was conducted of all consecutively treated patients who received single-implant tooth rehabilitation in combination with sinus augmentation. Implant survival rate and peri-implant conditions, such as marginal bone resorption (mm), pocket depth (mm), Plaque and Bleeding Indices, and Periotest values, were compared for the different augmentation procedures. RESULTS: Fifty-one patients were treated with 54 screw-type single implant-supported restorations in the posterior maxilla in combination with isolated sinus floor augmentation. Depending on the residual ridge height and the intended augmentation height, sinus lift elevation was performed either in a 1-stage lateral approach (25 patients, 28 implants), in a 2-stage lateral approach (12 patients, 12 implants), or with the osteotome technique (14 patients, 14 implants). The predominant use of long implants provided for a favorable implant-crown ratio (> 1.0) and produced an overall clinical survival rate of 100% over the observation period (44.5 +/- 22.7 months), with no differences between the augmentation procedures and implant types used. The most frequent site for single-tooth replacement in combination with sinus floor augmentation was the first molar region (61%). Implants with wider diameters (94% 2 4.3 mm) were used in this region. The most frequent intraoperative complication was tearing of the sinus membrane (58%) as a result of the restricted access for the lateral 1- or 2-stage approach, and the most frequent prosthetic complication was crown loosening. CONCLUSION: On the basis of this retrospective review, the following was observed: (1) Successful function and excellent peri-implant parameters may be anticipated for single implant-supported restorations placed in conjunction with sinus elevation procedures. (2) Clinical and radiographic examinations demonstrated similar conditions for single-tooth restorations despite the use of different surgical approaches to sinus augmentation. (More than 50 references).     

Cemented versus screw-retained implant-supported single-tooth crowns: a 4-year prospective clinical study

PURPOSE: The purpose of this controlled prospective clinical study was to compare cemented and screw-retained implant-supported single-tooth crowns followed for 4 years following prosthetic rehabilitation with respect to peri-implant marginal bone levels, peri-implant soft tissue parameters, and prosthetic complications. MATERIALS AND METHODS: Twelve consecutive patients were selected from a patient population attending the Implantology Department at the University of Padova. They all presented with single-tooth bilateral edentulous sites in the canine/premolar/molar region with adequate bone width, similar bone height at the implant sites, and an occlusal scheme that allowed for the establishment of identical occlusal cusp/fossa contacts. Each patient received 2 identical implants (1 in each edentulous site). One was randomly selected to be restored with a cemented implant-supported single-tooth crown, and the other was restored with a screw-retained implant-supported single-tooth crown. Data on peri-implant marginal bone levels and on soft tissue parameters were collected 4 years after implant placement and analyzed to determine whether there was a significant difference with respect to the method of retention (cemented versus screw-retained). RESULTS: All patients completed the study. All 24 implants survived, resulting in a cumulative implant success rate of 100%. Statistical analysis revealed no significant differences between the 2 groups with respect to peri-implant marginal bone levels and soft tissue parameters. DISCUSSION: The data obtained with this study suggested that the choice of cementation versus screw retention for single-tooth implant restorations is likely not based on clinical results but seems to be based primarily on the clinician's preference. CONCLUSIONS: Within the limitations of this study, the results indicate that there was no evidence of different behavior of the peri-implant marginal bone and of the peri-implant soft tissue when cemented or screw-retained single-tooth implant restorations were provided for this patient population.     

A 4-Year Prospective Study to Assess Peri-Implant Hard and Soft Tissues Adjacent to Titanium Versus Gold-Alloy Abutments in Cemented Single Implant Crowns

PURPOSE: The purpose of this prospective clinical study was to compare titanium and gold-alloy abutments when used with cemented, implant-supported single-tooth crowns. For 4 years following prosthodontic rehabilitation, these abutments were evaluated with respect to peri-implant marginal bone levels and peri-implant soft tissue parameters. MATERIALS AND METHODS: During the years 1998 to 2000, 20 patients were selected from a patient population receiving treatment in the Implantology Department at the University of Padova, Italy. They all presented with single-tooth bilateral edentulous sites in the premolar/molar region with adequate bone width, similar bone height on each side, and an occlusal scheme that allowed for the establishment of identical occlusal cusp/fossa contacts on each side. Each subject received two identical implants (one in each edentulous site). One was randomly selected to be restored with a titanium abutment and a cemented implant-supported single-tooth crown, and the other was restored with a gold-alloy abutment and a cemented implant-supported single tooth crown. Data on peri-implant marginal bone levels and soft tissue parameters were collected for 4 years after abutment and crown insertion placement and analyzed to determine whether there was a significant (p< .001) difference with respect to the type of abutments (titanium vs. gold alloy) used. RESULTS: All subjects completed the study. All 40 implants survived, resulting in a cumulative implant success rate of 100%. Statistical analysis revealed no significant differences between the two groups with respect to peri-implant marginal bone levels and soft tissue parameters. CONCLUSIONS: Within the limitations of this study, the results indicate that there was no evidence of different response with the peri-implant marginal bone and soft tissue when titanium or gold-alloy abutments were used in conjunction with the cemented, single-tooth implant restorations provided for this limited patient population. There was no evidence of different behavior of peri-implant marginal bone and of peri-implant soft tissue when titanium abutments or gold-alloy abutments were used for cemented single-tooth implant restorations in this limited patient population.     

Frialit-2种植体在修复前牙缺失中的应用

目的 评价Frialit－2种植体修复前牙缺失的临床疗效。方法 即刻植入组（20例）与常规植入组（34例），共植入66个Frialit－2种植体，均以单冠作义齿修复。结果 经0．5－4年的临床观察，即刻植入组与常规植入组成功率分别为90．0％与96．6％。结论 常规植入组的疗效优于即刻植入组；FRIALIT－2种植体修复前牙缺失可获得良好的功能与美学效果。     

Aesthetic outcome of single-tooth implant restorations following early implant placement and guided bone regeneration: crown and soft tissue dimensions compared with contralateral teeth

Objectives: The aim of this study was to compare crown and soft tissue dimensions of single-tooth implant restorations following early implant placement and guided bone regeneration (GBR) with contralateral non-restored teeth.
Material and methods: Twenty-seven patients treated by one and the same surgeon and prosthodontist to restore a single-tooth gap with a class I bone defect in the premaxilla by means of an implant-supported restoration were reviewed. Patients were examined at least 6 months following placement of the crown. All implants had been inserted 6–8 weeks following tooth extraction in conjunction with GBR. At evaluation, crown dimensions, soft tissue dimensions, clinical conditions and patients' aesthetic satisfaction were assessed by one clinician who had not been involved in the treatment.
Results: Implant-supported crowns were not significantly longer than contralateral teeth and midfacial soft tissues showed comparable levels after on average 21 months of function. Our data also indicated significant papilla loss especially at the distal aspect of the implants. As the patient's aesthetic appreciation was favourable in 88% of the cases, this appeared to be of trivial importance.
Conclusions: Favourable aesthetics may be achieved for single-tooth implant restorations following early implant placement and GBR. The impact of the latter on papilla levels, however, remains to be determined in longitudinal studies.     

A short-term clinical evaluation of immediately restored maxillary TiOblast single-tooth implants

PURPOSE: The purpose of this study was to evaluate the short-term clinical outcome of single-tooth implants placed in the maxilla and immediately restored using cementless friction-fit temporary crowns. MATERIALS AND METHODS: Twenty-five patients consecutively referred to a private specialist practice for the replacement of failing or missing maxillary teeth were treated by means of immediate temporization of their single-tooth implants. Where teeth were still present, implants were placed immediately following extraction. Provisional crowns were fabricated on a special friction-fit coping by means of autopolymerizing acrylic resin. Definitive crowns were placed a mean of 4.5 months after surgery. Implant survival was recorded along with the level of the marginal bone relative to a fixed reference point 1 year after placement. Any adverse soft tissue changes were also noted. RESULTS: A total of 28 Astra Tech ST dental implants were placed. The overall survival rate at the end of the study was 96.4% for implants which were in function for periods ranging from 15.7 to 27 months. One patient, a smoker, lost 1 implant within 1 month of surgery. Mean marginal bone loss was 0.40 mm (range 0 to 1.53 mm) 1 year after placement of the implants. Many implants (37.5%) had no observed bone loss. No implants or crowns have been lost during the functional loading period. One implant was associated with an unfavorable recession of soft tissues; however, most maintained an esthetic gingival architecture. Eleven of 28 provisional restorations needed treatment; 6 required replacement during the temporization period, and 5 required cementation because of looseness. The ease of removal of the crowns allowed regular access for irrigation with chlorhexidine and thus maintenance of soft tissue health. DISCUSSION: The need to provide provisional restorations for single-tooth gaps often presents challenges. An immediate temporary partial denture or adhesive prosthesis may be unacceptable or impractical. The current study describes a simple method for the immediate temporization of single-tooth implants. The results did not indicate any negative influence on osseointegration or short-term survival once the implants were functionally loaded. CONCLUSION: Immediate temporization of maxillary single-tooth implants can be both safe and predictable, and it appears that the procedure can yield favorable soft tissue esthetics.     

Multicenter retrospective analysis of the solid-screw ITI implant for posterior single-tooth replacements

PURPOSE: This report involves the retrospective analysis of ITI implants placed and/or restored by a group of 7 clinicians located throughout the United States (5 periodontists and 2 prosthodontists). MATERIALS AND METHODS: Six hundred seventy-five posterior single-tooth implants were restored in 471 patients (average time of loading 21.30 months, with a range of 1 to 78 months). Three hundred seventy implants and 71 implants were placed in mandibular and maxillary molar sites, respectively, and 108 and 126 were placed in mandibular and maxillary premolar sites, respectively. RESULTS: A cumulative survival rate of 99.1% was obtained for all sites (6 failures). The survival rates for individual sites were as follows: 98.4% mandibular molars, 100% maxillary molars, 100% mandibular premolars, and 100% maxillary premolars. "At-risk" implants (1 to 2 mm of radiographic bone loss) were noted at 5 sites. DISCUSSION: Minimal restorative problems were found with either screw-retained (n = 71) or cemented restorations on solid abutments (n = 600); 80.3% of screw-retained and 98.2% of cemented restorations were free of complications, respectively. Patient satisfaction scores were high (97.4%) as determined by the Patient Satisfaction Questionnaire. CONCLUSION: The data suggest that solid-screw (4.1 or 4.8 mm wide) ITI implants can be a satisfactory choice for posterior single-tooth restorations.