Abstract Purpose The basic aim of the present study was to analyze the results of implant failures in two different implant populations, and how these results may vary depending on how the data are compiled and analyzed. Materials and Methods Two groups of consecutively treated patients were included who had been provided with either one single implant in a partially edentulous upper jaw (1881 patients) or four to eight implants in an edentulous upper jaw (2031 patients/12 454 implants). The risk of implant failure in the two groups separately and in combination was statistically compared by using uni‐ and multivariable analyses. Results The two groups showed significant differences in inclusion, surgical treatment protocols, and the risk of implant failures ( P < .05). Overall, 25‐year patient‐level cumulative survival rates (CSRs) were 75.8% and 96.3% for edentulous and single implant treatment, respectively. “Dental condition” was the variable associated with the greatest risk of implant failure (HR 6.00; edentulous). Only one variable was significantly associated with the risk of implant failure in all tested groups (“time after surgery”; a decreased risk was observed over time), and more variables were statistically associated with implant failures in the edentulous group than in the single implant group. Conclusions Edentulous patients present a significantly and substantially higher risk of implant failures than patients provided with a single implant. When patients with different clinical conditions are pooled into the same group, patients with the most common condition in the total group have greatest impact on the result of the total group. Based on the present observations, risk patterns for a certain oral condition are not necessarily comparable with the implant treatment received by other patients, and the external validity may be limited in small, homogeneous groups of patients.
ABSTRACT Background: The available jawbone volume is regarded as one of the most important factors when assessing the prognosis of oral implants in the rehabilitation of the edentulous maxilla. Purpose: The aim of the current investigation was to retrospectively evaluate and compare the outcome of implants placed in edentulous maxillae with either wide or narrow jaw shapes. The marginal bone loss and implant cumulative survival rates (CSRs) were calculated and analyzed with special reference to smoking habits. Materials and Methods: The study included 75 individuals with edentulous maxillae, of which 33 patients exhibited wide (group A) and 42 patients exhibited narrow jaw shapes (group B). A total of 506 turned Brånemark System® (Nobel Biocare AB, Göteborg, Sweden) implants were inserted (226 in group A and 279 in group B) and followed clinically up to 7 years. Smoking habits were recorded. Radiographs were obtained at connection of prostheses, and at the 1‐ and 5‐year follow‐up visit. The marginal bone loss was calculated for the groups and analyzed using t ‐test. Results: Twenty‐eight implants were lost during the study period, revealing implant CSRs at 7 years of 94.6% (11/226) and 93.6% (17/279) for wide and narrow crests, respectively. No difference in marginal bone loss was seen between the two groups, although a trend toward more bone loss was recorded for patients with wide crests. Smoking habits were more common in group A (45%) than in group B (31%). During the first year of function, smokers lost significantly more marginal bone than nonsmokers ( p = .0447), albeit this difference did not prevail ( p > .05) at the end of the study period. Conclusions: The implant CSRs at 7 years were equally good for the two groups of patients with various jaw shapes. Initially, smokers showed significantly more marginal bone loss than nonsmokers.
Abstract Background Few large‐scale follow‐up studies are reported on routine implant treatment. Purpose To report retrospective data on peri‐implantitis and overall implant failures at one private referral clinic (effectiveness study). Materials and Methods A total of 1017 patients were consecutively provided with 3082 implants with an anodized surface during 1592 operations between 2000 and 2011. All patients with any of four events of problems were identified; “peri‐implantitis,” “surgery related to peri‐implantitis,” “overall implant failure,” and “late implant failures.” A logistic multivariate analysis was performed to identify possible factors with association to the four events. Results “Lower jaw surgery” (HR = 3.03) and “immediate gingival grafting” at implant surgery (HR = 3.34) were factors with the highest risk associated to the two peri‐implantitis events, respectively. Risk of peri‐implantitis increased by year of inclusion from year 2000 (HR = 1.28). “Overall implant failures” were associated to “smoking” (HR = 2.11), “surgical technique” (highest for direct placement; HR = 1.67), and “type of implant” (NobelActive CC; HR = 2.48). NobelActive CC was more used in upper jaws, using immediate or one‐stage surgery with bone and mucosa grafting procedures than other implants ( P < .05). Implants lost after first year only showed an association to “lower jaw” (HR = 2.63) and “early inflammation” (HR = 17.95). Conclusion Peri‐implantitis seem to be associated to surgical protocols more often in the posterior lower jaw in routine practice. The problems seem to increase during the inclusion period, possibly related to increased use of direct implant placement technique and grafting protocols. Early inflammatory problems have in the previous report on the present patient group been associated to the mid‐aged patient. Overall/late implant failures were shown to be associated to earlier inflammatory problems, smoking habits, surgical technique, and treatment in the posterior lower jaw.
Abstract Background Peri‐implant bone level values have been used as the clinical standard of reference to describe the status of a dental implant. Reduction of marginal bone levels in association with bleeding on probing have been claimed to be a sign of pathology and an indication of treatment needs. Purpose To assess the available evidence that peri‐implant bone loss is caused by infection. Materials and methods This article is a narrative review on the interpretation of marginal bone level changes around dental implants as a consequence of infection. Results and conclusions There is evidence that plaque accumulation induces an inflammatory reaction in the peri‐implant soft tissues and that resumption of plaque control measures results in the reduction of the inflammation. Since plaque is always present in the oral cavity, a cause‐effect relationship between plaque accumulation and peri‐implantitis, defined as inflammation of the peri‐implant soft tissues associated with marginal bone loss has been difficult to validate and has not been proven so far. There is no evidence of the mechanisms involved in the tissue reactions resulting in the conversion from a state of an inevitable inflammation contained in the soft tissues to a state of inflammation involving the loss of peri‐implant marginal bone. There is today no consensus whether implants should be expected to be surrounded by tissues which are completely free from inflammation, or that an “immune‐driven”, chronic, subclinical inflammation should be expected at the foreign body implant. The infectious origin theory appears to be mainly supported by ligature‐induced experimental peri‐implantitis investigations in animal models that suffer of several methodological problems, and therefore, provide misleading information with regards to human clinical applications in large, routine populations.
Thirty routine patients, provided with fixed prostheses supported by osseointegrated Brånemark implants in edentulous lower jaws, were arranged into three different groups with regard to design of the metal framework. Ten patients received cast gold alloy frames and the other two groups were provided with two different designs of welded titanium frames. The fit of the completed prostheses was measured in three dimensions (3-D) in relation to the master cast, by means of a photogrammetric technique, prior to insertion. Mean 3-D distortion of the centre point of the gold cylinder was 42 (s.d. 8) microns for the cast framework. The corresponding mean distortion for the two designs of titanium frameworks was 43 (s.d. 16) and 36 (s.d. 10) microns, respectively. Least distortion was observed in vertical direction for all three designs. None of the different designs of metal frames showed a significantly better fit (P > 0.05), but the cast and oldest titanium framework design presented a much wider range of distortion. This indicated a higher risk of sectioning and resoldering during the fabrication of the prostheses as compared to the more consistently fabricated prostheses, with a new titanium framework design.
ABSTRACT Background: Comparative long‐term knowledge of different framework materials in the edentulous implant patient is not available for 15 years of follow‐up. Purpose: To report and compare a 15‐year retrospective data on implant‐supported prostheses in the edentulous mandible provided with laser‐welded titanium frameworks (test) and gold alloy frameworks (control). Materials and Methods: Altogether, 155 patients were consecutively treated with abutment‐level prostheses with two early generations of fixed laser‐welded titanium frameworks (titanium group). Fifty‐three selected patients with gold alloy castings formed the control group. Clinical and radiographic 15‐year data were collected and compared for the groups. Results: All patients who were followed up for 15 years ( n = 72) still had a fixed prosthesis in the mandible at the termination of the study. The 15‐year original prosthesis cumulative survival rate (CSR) was 89.2 and 100% for titanium and control frameworks ( p = .057), respectively (overall CSR 91.7%). The overall 15‐year implant CSR was 98.7%. The average 15‐year bone loss was 0.59 mm (SD 0.56) and 0.98 mm (SD 0.64) for the test and control groups ( p = .027), respectively. Few (1.3%) implants had >3.1‐mm accumulated bone loss after 15 years. The most common complications for titanium frameworks were resin or veneer fractures and soft tissue inflammation. Fractures of the titanium metal frame were observed in 15.5% of the patients. More patients had framework fractures in the earliest titanium group (Ti‐1 group) compared to the gold alloy group ( p = .034). Loose and fractured implant screw components were few (2.4%). Conclusion: Predictable overall long‐term results could be maintained with the present treatment modality. Fractures of the metal frames and remade prostheses were more common in the test group, and the gold alloy frameworks had a tendency to work better when compared with welded titanium frameworks during 15 years. However, on the average, more bone loss was observed for implants supporting gold alloy frameworks.
Objetivo: El objetivo de este estudio fue documentar la supervivencia clinica a largo plazo de los implantes unitarios colocados con superficies mecanizadas y moderadamente rugosas en la practica clinica habitual. Materiales y metodos: Se incluyeron todos los pacientes que fueron tratados consecutivamente en un centro especializado con implantes bajo coronas unitarias desde 1982 hasta 2013. En todos estos pacientes se recogieron los datos de los fracasos de implantes, asi como de la ultima exploracion realizada en la clinica, y despues se calcularon las tasas de supervivencia acumulada (TSA) de los pacientes tratados en el maxilar superior o inferior con superficies mecanizadas o moderadamente rugosas, respectivamente. Resultados: En total, 2.417 pacientes (2.665 intervenciones) fueron tratados con 3.211 implantes unitarios durante el periodo de inclusion (31 anos). En total 573 de estos pacientes (615 intervenciones, 754 implantes) tuvieron un seguimiento de hasta al menos 10 anos. Las proporciones globales de pacientes con un seguimiento de 5 a 25 anos fueron descendiendo del 68,2% al 37% de los pacientes tratados. Se constato un mayor cumplimiento del seguimeinto en los pacientes tratados durante el primer periodo de inclusion. La TSA de los pacientes al cabo de 15 y 10 anos tras las colocacion de los implantes en el maxilar superior fue del 95,8% en las superficies mecanizadas y del 98,5% para las superficies moderamente rugosas. La TSA correspondiente en los pacientes al cabo de 10 y 25 anos tras colocacion en el maxilar inferior fue del 95,1% y el 97,2%, respectivamente. No se refirieron fracasos de implantes tras 10 anos de seguimiento. Conclusion: a largo plazo cabe esperar que se pierda un numero significativo de pacientes en el seguimiento en la practica clinica habitual. El tratamiento con implantes unitarios es un procedimiento terapeutico globalmente predecible a largo plazo con una tasa de fracaso baja en los implantes con una superficie moderadamente rugosa colocados en el maxilar superior. Esta diferencia parece ya establecerse en la primera fase de la osteointegracion.
