Short implants placed one-stage in maxillae and mandibles: a retrospective clinical study with 1 to 9 years of follow-up.

BACKGROUND: The use of short implants (7-8.5 mm) has historically been associated with lower survival rates than for longer implants. However, recent clinical studies indicate that short implants may support most prosthetic restorations quite adequately, but still clinical documentation is sparse. PURPOSE: The purpose of this study was to report on the placement of short Brånemark implants, testing the hypothesis that short implants in atrophied jaws might give similar long-term implant survival rates as longer implants used in larger bone volumes. MATERIALS AND METHODS: This retrospective clinical study included 237 consecutively treated patients with 408 short Brånemark implants supporting 151 fixed prostheses. One hundred thirty-one of the implants were 7-mm long, and 277 were 8.5-mm long. Final abutments were delivered at the time of surgery, and final prostheses were delivered 4 to 6 months later. RESULTS: One hundred and twenty six of the 7-mm implants (96%) have passed the 1-year follow-up; 110 (84%), the 2-year follow-up; and 88 (67%), the 5-year follow-up. Five implants failed in four patients before the 6-month follow-up, giving a cumulative survival rate of 96.2% at 5 years. The average bone resorption was 1 mm (SD=0.6 mm) after the first year and 1.8 mm (SD=0.8 mm) after the fifth year of function. Two hundred sixty nine of the 8.5-mm implants (97%) have passed the 1-year follow-up; 220 (79%), the 2-year follow-up; and 142 (51%), the 5-year follow-up. Eight implants failed in seven patients before the 6-month follow-up, giving a cumulative survival rate of 97.1% at 5 years. The average bone resorption was 1.3 mm (SD=0.8 mm) after the first year and 2.2 mm (SD=0.9 mm) after the fifth year of function. CONCLUSIONS: The cumulative survival rates of 96.2 and 97.1% at 5 years for implants of 7.0- and 8.5-mm length, respectively, indicate that one-stage short Brånemark implants used in both jaws is a viable concept.

Validity and clinical significance of biomechanical testing of implant/bone interface.

PURPOSE: The aim of this paper was to review the clinical literature on the Resonance frequency analysis (RFA) and Periotest techniques in order to assess the validity and prognostic value of each technique to detect implants at risk for failure. MATERIAL AND METHODS: A search was made using the PubMed database to find clinical studies using the RFA and/or Periotest techniques. RESULTS: A limited number of clinical reports were found. No randomized-controlled clinical trials or prospective cohort studies could be found for validity testing of the techniques. Consequently, only a narrative review was prepared to cover general aspects of the techniques, factors influencing measurements and the clinical relevance of the techniques. CONCLUSIONS: Factors such as bone density, upper or lower jaw, abutment length and supracrestal implant length seem to influence both RFA and Periotest measurements. Data suggest that high RFA and low Periotest values indicate successfully integrated implants and that low/decreasing RFA and high/increasing Periotest values may be signs of ongoing disintegration and/or marginal bone loss. However, single readings using any of the techniques are of limited clinical value. The prognostic value of the RFA and Periotest techniques in predicting loss of implant stability has yet to be established in prospective clinical studies.

Immediate function with the zygomatic implant: a graftless solution for the patient with mild to advanced atrophy of the maxilla.

PURPOSE: In many edentulous maxillae, posterior alveolar atrophy calls for bone grafting. Patient treatment acceptance is increased by eliminating grafting using tilted implants, especially the zygomatic implant in combination with immediate function. The purpose of this study was to evaluate a protocol for immediate function (within 2 hours) of 2 zygomatic and 4 standard implants (Nobel Biocare) supporting a fixed prosthesis in the completely edentulous maxilla. MATERIALS AND METHODS: This clinical study included 14 patients with 83 immediately loaded implants (28 bilateral zygomatic and 55 premaxillary implants) supporting a complete maxillary denture converted to a fixed provisional prosthesis immediately following the surgical procedure. After 6 months of use, a new fixed metal-supported prosthesis was fabricated. RESULTS: Fourteen patients treated with immediate loading of zygomatic implants were followed for at least 12 months. All patients reported minimization of postoperative pain and security during speech, animation, and mastication. No failures occurred during the follow-up period. DISCUSSION: The patients in the study could have been candidates for sinus grafting. With the present concept these patients benefited from a less invasive procedure (1 surgical procedure and no grafting) and immediate rehabilitation (prosthesis attached directly after surgery). CONCLUSION: The high survival rate, increase in patients' immediate functional ability, and reduction of morbidity following the surgical procedure render this procedure a viable treatment option for the completely edentulous maxilla.

Early loading of interforaminal implants immediately installed after extraction of teeth presenting endodontic and periodontal lesions.

BACKGROUND: Infection in tooth extraction sites has traditionally been considered an indication to postpone implant insertion until the infection has been resolved. PURPOSE: The aim of this study was to evaluate the survival rate of early-loaded implants placed immediately after extraction of teeth with endodontic and periodontal lesions in the mandible. MATERIALS AND METHODS: Twenty patients in need of mandibular implant treatment and with teeth showing signs of infection in the interforaminal area were included in the study. The patients received four to six implants (Brånemark System, Nobel Biocare AB, Göteborg, Sweden) in or close to the fresh extraction sockets and received a provisional prosthesis within 3 days. Final prostheses were delivered after 3 to 12 months. The surgical protocol paid special attention to the preservation of high implant stability and control of the inflammatory response. The patients were followed up for 15 to 44 months. RESULTS: No implants were lost, resulting in a 100% survival rate. A mean marginal bone loss of 0.7 mm (SD 1.2 mm) was registered during the observation period. No signs of infection around the implants were detected at any follow-up visit. CONCLUSION: A high survival rate can be achieved for immediately placed and early-loaded implants in the mandible despite the presence of infection at the extracted teeth.

All-on-4 immediate-function concept with Brånemark System implants for completely edentulous maxillae: a 1-year retrospective clinical study.

BACKGROUND: Immediate implant function has become an accepted treatment modality for fixed restorations in totally edentulous mandibles, whereas experience from immediate function in the edentulous maxilla is limited. PURPOSE: The purpose of this study was to evaluate a protocol for immediate function (within 3 hours) of four implants (All-on-4, Nobel Biocare AB, Göteborg, Sweden) supporting a fixed prosthesis in the completely edentulous maxilla. MATERIALS AND METHODS: This retrospective clinical study included 32 patients with 128 immediately loaded implants (Brånemark System TiUnite, Nobel Biocare AB) supporting fixed complete-arch maxillary all-acrylic prostheses. A specially designed surgical guide was used to facilitate implant positioning and tilting of the posterior implants to achieve good bone anchorage and large interimplant distance for good prosthetic support. Follow-up examinations were performed at 6 and 12 months. Radiographic assessment of the marginal bone level was performed after 1 year in function. RESULTS: Three immediately loaded implants were lost in three patients, giving a 1-year cumulative survival rate of 97.6%. The marginal bone level was, on average, 0.9 mm (SD 1.0 mm) from the implant/abutment junction after 1 year. CONCLUSION: The high cumulative implant survival rate indicates that the immediate function concept for completely edentulous maxillae may be a viable concept.

Immediate/early function of Brånemark System TiUnite implants in fresh extraction sockets in maxillae and posterior mandibles: an 18-month prospective clinical study.

BACKGROUND: The advantages of placing implants in fresh extraction sockets and putting them in immediate/early function are many. A predicable protocol opens the possibility of performing a single surgical procedure, giving the patient a temporary prosthesis immediately, and minimizing the shrinkage of hard tissue and soft tissue recession. PURPOSE: The aim of the present study was to develop a strict protocol for and to evaluate the feasibility of immediate/ early function on implants placed in fresh extraction sockets located in maxillae and posterior mandibles, including defects around the implants treated according to a regenerative procedure. MATERIALS AND METHODS: Nineteen patients were treated after tooth extraction according to an immediate function protocol and were observed for 18 months. Fifty Mk IV TiUnite (Nobel Biocare AB, Göteborg, Sweden) implants were installed in partially edentulous areas in maxillae (n = 17) and posterior mandibles (n = 5). Implants were installed directly into the alveoli, and the temporary prostheses were connected immediately after surgery (n = 11) or within 7 days, that is, an "early function" procedure (n = 11). Thirteen implants did not require any type of regenerative procedure, whereas the remaining 37 implants had filling with autogenous bone, 4 of which also had a resorbable membrane. Standardized intraoral radiographs were taken for evaluation of marginal bone level, and 38 of the implants were systematically checked by resonance frequency analysis. RESULTS: All patients were followed for 18 months, and none of the 50 implants failed. However, one implant showed signs of failure after 6 weeks, but once the occlusal load was removed, the implant regained its stability completely, no longer demonstrated symptoms, and could be used successfully for prosthetic rehabilitation. The mean value of the implant stability quotient was 60 at baseline (range 45-75) and 63 after 6 months (range 46-75). The marginal bone resorption was 0.9 mm (SD 1.1 mm; n = 48) 18 months after implant insertion (1 year after final prosthesis). CONCLUSION: The immediate placement of implants into fresh extraction sockets combined with immediate/early function procedures seems to be a safe and reliable procedure when using a strict protocol.

Immediate functional loading of Brånemark System implants with enhanced initial stability: a prospective 1- to 2-year clinical and radiographic study.

BACKGROUND: The interest in the benefits of immediate loading of titanium implants has recently involved fixed prostheses for partially edentulous areas. The advantages of this approach well justify the need for extending the procedure to all regions of the mouth. Current available clinical literature on this subject is incomplete. PURPOSE: The purpose of this study is to investigate the clinical outcome of the immediate loading of Brånemark System implants (Nobel Biocare AB, Gothenburg, Sweden) inserted with enhanced initial stability principally in posterior sites (78%). MATERIALS AND METHODS: The present study was conducted in 26 consecutively treated patients. A total of 50 Brånemark System machined surface implants were placed supporting 30 fixed temporary partial dentures in light occlusion. All implants were followed up for a minimum of 1 year of function. Minimum requirements for immediate loading were proposed. Bone quality and quantity were classified according to Lekholm and Zarb's criteria. Stability of the marginal bone level, both mesial and distal, was measured on the basis of radiographic analysis. Implant survival rate was calculated according to Kaplan-Meier analysis. The peak insertion torque employed during fixture placement was between 40 and 72 Ncm, except in the case of one implant that was lost. RESULTS: Overall survival rate was 98%. An unpaired t-test revealed bone remodeling conforming to biologic width establishment (p <.005). CONCLUSIONS: Within the limit of this study, immediate loading appears to be a viable procedure in posterior sites and for a growing number of clinical indications. Enhanced implant stability and light occlusion seem to be security factors. In spite of unfavorable conditions such as the presence of quality 4 bone and a lack of splinting, all implants with enhanced primary stability survived.

"All-on-Four" immediate-function concept with Brånemark System implants for completely edentulous mandibles: a retrospective clinical study.

BACKGROUND: Immediate-function Brånemark System implants (Nobel Biocare AB, Gothenburg, Sweden) have become an accepted alternative for fixed restorations in edentulous mandibles, based on documented high success rates. Continuous development is ongoing to find simple protocols for their use. PURPOSE: The purpose of this study was to develop and document a simple, safe, and effective surgical and prosthetic protocol for immediate function (within 2 hours) of four Brånemark System implants supporting fixed prostheses in completely edentulous mandibles: the "All-on-Four" concept. MATERIALS AND METHODS: This retrospective clinical study included 44 patients with 176 immediately loaded implants, placed in the anterior region, supporting fixed complete-arch mandibular prostheses in acrylic. In addition to the immediately loaded implants, 24 of the 44 patients had 62 rescue implants not incorporated in the provisional prostheses but incorporated in final prostheses later on. RESULTS: Five immediately loaded implants were lost in five patients before the 6-month follow-up, giving cumulative survival rates of 96.7 and 98.2% for development and routine groups, respectively. The prostheses' survival was 100%, and the average bone resorption was low. CONCLUSIONS: The high cumulative implant and prostheses survival rates indicate that the "All-on-Four" immediate-function concept with Brånemark System implants used in completely edentulous mandibles is a viable concept.

Immediate/early loading of dental implants: a report from the Sociedad Española de Implantes World Congress consensus meeting in Barcelona, Spain, 2002.

BACKGROUND: Immediate/early loading protocols are becoming frequently used in implant dentistry, but the prerequisites for achieving good results and the limitations of such protocols are not fully known. Moreover, the terminology used in immediate/early loading is still confusing. PURPOSE: The purpose of this article is to present the outcome of a consensus meeting on immediate/early loading. MATERIALS AND METHODS: A consensus meeting was organized during the Sociedad Española de Implantes World Congress in Barcelona on May 23, 2002, with the objective to present and discuss the experiences from immediate/early loading protocols in dental implant treatment. The purpose was also to discuss definitions of the terminology used in immediate/early loading. The consensus meeting agenda included presentations from invited experts, followed by a consensus discussion. RESULTS: A consensus statement was agreed on. CONCLUSIONS: Multiple independent investigators have demonstrated that immediate/early loading of implants is possible in many clinical situations; however, additional documentation is required.

The Marius implant bridge: surgical and prosthetic rehabilitation for the completely edentulous upper jaw with moderate to severe resorption: a 5-year retrospective clinical study.

BACKGROUND: Patients seeking replacement of their upper denture with an implant-supported restoration are most interested in a fixed restoration. Accompanying the loss of supporting alveolar structure due to resorption is the necessity for lip support, often provided by a denture flange. Attempts to provide a fixed restoration can result in compromises to oral hygiene based on designs with ridge laps. An alternative has been an overdenture prosthesis, which provides lip support but has extensions on to the palate and considerations of patient acceptance. The Marius bridge was developed as a fixed bridge alternative offering lip support that is removable by the patient for hygiene purposes, with no palatal extension beyond normal crown-alveolar contours. PURPOSE: Implant-supported restorative treatment of completely edentulous upper jaws, as an alternative to a complete denture, is frequently an elective preference, and it requires significant patient acceptance beyond the functional improvement of chewing. Patients with moderate to severe bone resorption and thin ridges present additional challenges for adequate bone volume and soft-tissue contours. The purpose of this investigation was to develop a surgical and prosthetic implant treatment protocol for completely edentulous maxillae in which optimal lip support and phonetics is achieved in combination with substantial implant anchorage without bone grafting. MATERIALS AND METHODS: The Marius bridge is a complete-arch, double-structure prosthesis for maxillae that is removable by the patient for oral hygiene. The first 45 consecutive patients treated by one person (YF) in one center with this concept are reported, with 245 implants followed for up to 5 years after prostheses connection. RESULTS: The cumulative fixture survival rate for this 5-year retrospective clinical study was 97%. Five fixtures failed before loading, in five different patients, and two fixtures in the same patient failed at the 3-year follow-up visit. None of the bridges failed, giving a prostheses survival rate of 100%. The complications were few and mainly prosthetic: nine incidences of attachment component complications, one mesobar fracture, and three reports of gingivitis. All complications were solved or repaired immediately, with minimal or no interruption of prostheses use. CONCLUSIONS: Satisfactory medium-term results of survival and patient satisfaction show that the Marius bridge can be recommended for implant dentistry. The technique may reduce the need for grafting, because it allows for longer implants to be placed with improved bone anchorage and prostheses support. key words: clinical follow-up, complete arch, double structure, esthetics, maxilla, phonetics, tilted implants

Early function of splinted implants in maxillas and posterior mandibles using Brånemark system machined-surface implants: an 18-month prospective clinical multicenter study.

BACKGROUND: There are limited clinical data available for immediately or early loaded implants placed in posterior mandibles and maxillas. This is probably because bone density often is low in these areas, making it difficult to establish good initial implant stability. By eliminating countersinking and using slightly tapered implants (Brånemark System , Mk IV, Nobel Biocare AB, Gothenburg, Sweden), however, high initial implant stability might be achieved in these regions. PURPOSE: The aim of this study was to investigate the possibility of early application of implant function in oral locations where the bone density is often low, namely the maxilla and posterior mandible. MATERIALS AND METHODS: Thirty-one patients were included consecutively in the study, and 36 edentulous areas in maxillas and posterior mandibles were treated. All patients were nonsmokers in good general health. Bruxism and uncontrolled periodontal disease were exclusion criteria. One hundred twenty-four machined-surface implants were placed using an insertion torque of at least 40 Ncm. Temporary prostheses with narrow occlusal platforms, flat cusps, and light occlusal contacts were generally placed within 1 week and not exceeding 20 days from implant placement. RESULTS: Of the 124 implants installed, 4 failed, 1 in each of four patients, giving an overall survival rate of 96.8% after 18 months. Two implants failed in maxillas and two in mandibles. One implant in a maxilla and one in a mandible were lost in an early stage, and the other two were lost a few months after placement. The prostheses' survival was 100%. CONCLUSIONS: This study shows that early implant function rehabilitation in maxillas and posterior mandibles is viable using the present clinical protocol. The results are comparable with those of conventional two-stage protocols.

Immediate occlusal loading of single lower molars using Brånemark System Wide-Platform TiUnite implants: an interim report of a prospective open-ended clinical multicenter study.

BACKGROUND: First and second molars in the lower jaw are the most commonly missing teeth. As in other jaw regions with tooth loss, implant therapy is an attractive concept. Owing to the wide dimension of the molar teeth, wide implants seem to be a natural choice. However, wide implants in posterior mandibular regions sometimes present a problem. As an oxidized surface seems to facilitate implant integration and to result in a stronger fixation to bone, it was hypothesized that this surface would improve the performance of wide implants in posterior mandibles. As high initial stability most often is achieved in this region, it was hypothesized that the load per se is not a problem. PURPOSE: The purpose of the present study is to evaluate immediate loading of Brånemark System TiUnite Wide-Platform implants (Nobel Biocare AB, Gothenburg, Sweden) supporting single molar crowns in the lower jaw. MATERIALS AND METHODS: The study includes 44 patients treated in three separate private dental offices between March 2001 and June 2002. A total of 50 implants were placed, and all implants have passed the 6-month follow-up; 24 have been followed up for 1 year. All implants were provided with provisional crowns in centric occlusion at the time of surgery. RESULTS: No implant has been lost. Marginal bone levels were found in accordance with normal biologic width requirements. Resonance frequency analysis showed high and consistent implant stability. No biomechanical problems were found associated with the use of wide implants, and the potential physiologic problem in dense mandibular bone was eliminated. CONCLUSION: Although limited by being a short-term study, the result encourages immediate loading of single Brånemark System TiUnite Wide-Platform implants placed in the molar regions in the lower jaw.

Immediate and early function of Brånemark System implants placed in the esthetic zone: a 1-year prospective clinical multicenter study.

BACKGROUND: Immediate/early implant function means great benefits for patients and therapists because treatment time and cost can be substantially reduced. This concept has become an accepted alternative for complete arch fixed restorations in the mandible, and clinical documentation is emerging for other indications. PURPOSE: The purpose of this prospective clinical multicenter study was to evaluate the outcome of implants placed in incisor, canine, and premolar regions in maxillas or mandibles. Implants were loaded with provisional crowns and bridges on the same day or within a few days and were followed up for 1 year during function. MATERIALS AND METHODS: Four centers treated 76 patients each in need of an implant-retained prosthesis in the anterior and premolar regions in the maxilla or mandible. A total of 116 titanium implants with machined surfaces (Brånemark System , Nobel Biocare AB, Gothenburg, Sweden) were placed: 74 in maxillas and 42 in mandibles. Eighty-seven prostheses were made, of which 63 were single crowns and 24 were bridges (supported by 53 splinted implants). Twenty-two implants in 14 patients were placed in fresh extraction sites. The goal with the preparation and insertion technique was to achieve good primary implant stability and a minimum implant insertion torque of 30 Ncm before the implant was completely seated. The occlusion was adjusted to eliminate direct contact with the provisional prostheses. After 6 months, the patients received their permanent prostheses. Sixty-seven patients were followed for 1 year. RESULTS: Five implants were lost in five patients, three in the maxilla and two in the mandible. Four of the lost implants were single-tooth replacements and one was splinted. The cumulative survival rate (CSR) was 95.7% for all implants after 1 year and 93.7% and 98.1% for single-tooth and splinted implants, respectively. There were no implant losses in the extraction sites. CONCLUSIONS: The CSR of 96% at 1 year indicates that immediate function of Brånemark System implants placed in incisor to premolar regions in both jaws is a viable concept. More failures occurred with single-tooth replacements (6.3%) than with splinted implants (1.9%).

Early function of splinted implants in maxillas and posterior mandibles, using Brånemark System Tiunite implants: an 18-month prospective clinical multicenter study.

BACKGROUND: Immediate or early loading of implants placed in maxillas and posterior mandibles has been a concern as bone density is often low in these areas, making it difficult to establish good initial implant stability. By adapting implant design and insertion protocols, however, high initial implant stability may be achieved in these regions. Further, a modified implant surface texture has been proved to help in maintaining stability during the initial healing period. PURPOSE: The aim of the present study was to investigate the clinical performance of oxidized titanium implants (TiUnite, Nobel Biocare AB, Gothenburg, Sweden) when used for early function in the maxilla and in the posterior mandible, locations where the bone density often is low. A further aim was to evaluate the marginal bone level at oxidized implants and compare it with that of machined-surface implants used in a previous study. MATERIALS AND METHODS: Thirty-one patients were consecutively included in the study, and 37 edentulous areas in maxillas and posterior mandibles were treated. Bruxism and uncontrolled periodontal disease were exclusion criteria. Temporary prostheses were generally placed within 9 days but not after 16 days from implant placement. A previous study applying the same study design and clinical protocol but using machined-surface implants was used for comparisons. RESULTS: Of the 111 implants installed, 1 failed, giving an overall survival rate of 99.1% after 18 months. The prosthesis survival was 100%. The marginal bone resorption was 0.8 mm (standard deviation [SD], 1.0), as opposed to 1.6 mm (SD, 1.3) in the previous study with machined-surface implants, but was not statistically significantly different (p = .10). CONCLUSION: The present clinical protocol (aiming at high primary stability) and the use of oxidized titanium implants for early functional loading in the maxilla and the posterior mandible resulted in a high implant survival rate and a favorable marginal bone level during a follow-up of 18 months. The difference in marginal bone resorption between the oxidized implants in the present study and the machined implants from a previous investigation with the same study design was not statistically significant.

In vivo registration of force development with ceramic and acrylic resin occlusal materials on implant-supported prostheses.

PURPOSE: It has been hypothesized that the shock generation on implant-supported prostheses during chewing should generate higher implant loads if the veneering material is porcelain rather than acrylic resin. MATERIALS AND METHODS: The present study uses strain-gauged abutments to measure the force transferred to the implant after a shock has been applied. This was measured in vitro and in vivo in 5 patients. RESULTS: The different occlusal materials did not lead to different forces generated to the implants of the patients. DISCUSSION: From a practical point of view, the choice of occlusal material has no bearing per se on force generation to the implants. CONCLUSIONS: The present study demonstrated that there: (a) is a difference in resilience between acrylic resin and ceramic veneering materials, but (b) this difference is only measurable in in vitro where the force is generated by a shock only and the implant is rigidly anchored.

Immediate functional loading of Brånemark system implants in edentulous mandibles: clinical report of the results of developmental and simplified protocols.

PURPOSE: This report evaluates the 5-year results of 9 of 10 patients in a clinical investigation of immediate functional loading of Brånemark System implants in edentulous mandibles, and of 24 patients treated with a simplified protocol for the same indication. The purpose of the paper is to suggest a simple, reliable, and documented method for immediate implant loading of complete-arch mandibular prostheses. MATERIALS AND METHODS: Ten healthy patients in need of full-arch mandibular implant reconstruction (development group) were treated between December 1993 and December 1994 with 130 Brånemark System standard Implants, placed in fresh extraction and healed sites. Four implants per patient were immediately loaded with acrylic resin fixed prostheses. The prostheses were replaced by metal-framework conversion prostheses approximately 6 weeks later, and definitive metal-reinforced prostheses incorporating all implants were placed after second-stage surgery. An additional 24 patients were treated with a simplified protocol using a total of 144 implants placed between March 1997 and October 2000. In these patients, the acrylic resin prostheses were not disturbed for 3 months, and fewer implants were used with an increasing ratio of implants loaded. Eventually, all Implants were loaded immediately for the last patients treated. RESULTS: The prosthesis survival rate was 100% for the total material. In the developmental group, the implant cumulative survival rate was 80% for the immediately loaded implants after 5 years, while the 2-stage implants reached 96%. Bone level measurements showed no differences between immediate and 2-stage protocols for this group. The implant cumulative survival rate was 97% for the simplified treatment group. DISCUSSION AND CONCLUSION: A predictable and simple concept for loading of immediate implant prostheses in edentulous mandibles was demonstrated. Results from the development of this technique suggest that it may be essential to maintain the initial implant splinting over a healing period of about 3 months and that implant placement between the mental foramina provides optimal support.

Immediate and early function of implants placed in extraction sockets of maxillary infected teeth: a pilot study.

STATEMENT OF PROBLEM: Infection in tooth extraction sites has traditionally been considered an indication to postpone implant placement until the infection has been resolved. PURPOSE: The aim of this study was to evaluate the survival rate of immediate and early-loaded implants placed immediately after extraction of teeth with endodontic and periodontal lesions or root fracture in the maxilla. MATERIAL AND METHODS: Thirty-three patients with teeth judged to be unrestorable because of endodontic or periodontal lesions or root fracture were included in the study. After tooth extraction, 1 to 6 implants (n=76) were placed in each patient using flap or flapless surgery in fresh extraction sockets, and a fixed provisional prosthesis was placed immediately or within 36 hours. Definitive prostheses were inserted after 6 to 12 months. The treatment protocol considered initial implant and prosthesis stability and control of the inflammatory response. Clinical and radiographic analyses were performed to evaluate the treatment outcome. Data were reported using descriptive statistics. RESULTS: After 1 year, 2 implants were lost, resulting in a 97.4% survival rate. A mean (SD) marginal bone loss of -0.91 (1.50) mm was recorded during the observation period. No signs of infection around the implants were detected at any follow-up visit. There was a tendency towards less bone loss with the flapless protocol, -0.74 (1.34) mm, versus flap, -1.02 (1.60) mm, and less bone loss for single, -0.55 (1.52) mm, versus multiple restorations, -0.86 (1.24) mm, with the flapless approach. CONCLUSIONS: A high 1-year survival rate was achieved for immediately placed and immediately/early-loaded implants in the maxilla, despite the presence of infection in the location of the extracted teeth.

Tilting of splinted implants for improved prosthodontic support: a two-dimensional finite element analysis.

STATEMENT OF PROBLEM: Presence of the maxillary sinus or the mental foramen may prevent implant treatment in the posterior maxilla or mandible. Tilting of distal implants supporting fixed restorations may be a valid treatment alternative. PURPOSE: The aim of this study was to evaluate if tilting of splinted implants affects stress distribution in the bone surrounding the implant cervix, and to investigate if the use of tilted implants as distal abutments is biomechanically superior to the use of distal cantilevers. MATERIAL AND METHODS: A 2-dimensional (2-D) model for finite element analysis was developed using two 13-mm implants splinted by a titanium beam, 16 x 3 mm. The implants were embedded in bone blocks, simulating different bone properties. A small crater was created in the marginal bone around the tilted implant to simulate physiologic bone remodeling. The model with a distal cantilever 7 mm long and a distal implant was compared to a model in which the distal implant (13 or 19 mm) was tilted 45 degrees and supported the distal end of the cantilever. A force of 50 N was applied via the beam. RESULTS: The stress at the most coronal bone-to-implant contact was identical irrespective of the angle of tilt, demonstrating that tilting of splinted implants does not result in increased stress. The cantilevered model showed that the use of cantilevers results in higher stress in the marginal bone around implants. This stress is reduced to "normal" levels when the cantilever arm is negated by the distal implant being apically inclined to support the distal end of the cantilever. Use of a longer implant only reduces the stress marginally. CONCLUSIONS: Within the limitations of this 2-D finite element analysis, it appears that distal tilting of implants splinted by fixed restorations does not increase bone stress compared to normally placed, vertical implants. There is a biomechanical advantage in using tilted distal implants rather than distal cantilever units.

Implants placed in immediate function in periodontally compromised sites: a five-year retrospective and one-year prospective study.

STATEMENT OF PROBLEM: Placing implants in periodontally compromised sites is generally considered a risk factor. Good results have been reported when rehabilitating partial or complete edentulous sites in patients with a history of periodontitis. However, there is a need for more documentation of this treatment modality. PURPOSE: The purpose of this study was to report, retrospectively, on the placement of implants in periodontally compromised areas of the maxilla and mandible without a prior healing period and in immediate function. This study also presents a prospective preliminary 1-year report using a standardized clinical protocol, including a regenerative surgical procedure, control of the inflammatory response, a maintenance protocol, and use of an implant with an oxidized surface. MATERIAL AND METHODS: The clinical study encompassed 184 consecutively included patients with 433 implants (165 with a machined surface and 268 with an oxidized surface) placed in immediate function (140 in the maxilla and 293 in the mandible) supporting 218 fixed prostheses. Two groups were defined: the Retrospective group (using an unstandardized surgical technique and a majority of machined surface implants) with a retrospective approach and the Prospective group (using standardized surgical and maintenance protocols and oxidized surface implants) with a prospective approach. The 2 groups were evaluated for implant survival, clinical implant stability, bone resorption, absence of radiolucent areas around implants on the radiographs, and patient-reported function of the implants. Definitive prostheses were placed 6 months after the surgery. The data was analyzed using descriptive statistics. RESULTS: Thirteen implants were lost in 9 patients, providing a cumulative survival rate of 91% at 5 years for the Retrospective group. In the Prospective group, a 100% cumulative survival rate was recorded after 1 year. The average bone resorption (SD) was 1.2 mm (0.9 mm) and 1.1 mm (1.1 mm) after the first year for the Retrospective and Prospective groups, respectively, and 1.7 mm (1.0 mm) for the Retrospective group after the fifth year of function. CONCLUSIONS: The cumulative survival rate of 91% at 5 years for the Retrospective group is low compared to protocols for noncompromised situations, but the use of a standardized protocol together with oxidized surface implants seems to improve the treatment outcome and bring the survival rate to levels comparable to noncompromised situations.