Cristiano Tomasi

Bone dimensional variations at implants placed in fresh extraction sockets: a multilevel multivariate analysis

AIM To use multilevel, multivariate models to analyze factors that may affect bone alterations during healing after an implant immediately placed into an extraction socket. MATERIAL AND METHODS Data included in the current analysis were obtained from a clinical trial in which a series of measurements were performed to characterize the extraction site immediately after implant installation and at re-entry 4 months later. A regression multilevel, multivariate model was built to analyze factors affecting the following variables: (i) the distance between the implant surface and the outer bony crest (S-OC), (ii) the horizontal residual gap (S-IC), (iii) the vertical residual gap (R-D) and (iv) the vertical position of the bone crest opposite the implant (R-C). RESULTS It was demonstrated that (i) the S-OC change was significantly affected by the thickness of the bone crest; (ii) the size of the residual gap was dependent of the size of the initial gap and the thickness of the bone crest; and (iii) the reduction of the buccal vertical gap was dependent on the age of the subject. Moreover, the position of the implant opposite the alveolar crest of the buccal ridge and its bucco-lingual implant position influenced the amount of buccal crest resorption. CONCLUSIONS Clinicians must consider the thickness of the buccal bony wall in the extraction site and the vertical as well as the horizontal positioning of the implant in the socket, because these factors will influence hard tissue changes during healing.

Effectiveness of Implant Therapy Analyzed in a Swedish Population: Prevalence of Peri-implantitis

Peri-implantitis is an inflammatory disease affecting soft and hard tissues surrounding dental implants. As the global number of individuals that undergo restorative therapy through dental implants increases, peri-implantitis is considered as a major and growing problem in dentistry. A randomly selected sample of 588 patients who all had received implant-supported therapy 9 y earlier was clinically and radiographically examined. Prevalence of peri-implantitis was assessed and risk indicators were identified by multilevel regression analysis. Forty-five percent of all patients presented with peri-implantitis (bleeding on probing/suppuration and bone loss >0.5 mm). Moderate/severe peri-implantitis (bleeding on probing/suppuration and bone loss >2 mm) was diagnosed in 14.5%. Patients with periodontitis and with ≥4 implants, as well as implants of certain brands and prosthetic therapy delivered by general practitioners, exhibited higher odds ratios for moderate/severe peri-implantitis. Similarly, higher odds ratios were identified for implants installed in the mandible and with crown restoration margins positioned ≤1.5 mm from the crestal bone at baseline. It is suggested that peri-implantitis is a common condition and that several patient- and implant-related factors influence the risk for moderate/severe peri-implantitis (ClinicalTrials.gov NCT01825772).

Primary prevention of peri-implantitis: managing peri-implant mucositis

AIMS Over the past decades, the placement of dental implants has become a routine procedure in the oral rehabilitation of fully and partially edentulous patients. However, the number of patients/implants affected by peri-implant diseases is increasing. As there are--in contrast to periodontitis--at present no established and predictable concepts for the treatment of peri-implantitis, primary prevention is of key importance. The management of peri-implant mucositis is considered as a preventive measure for the onset of peri-implantitis. Therefore, the remit of this working group was to assess the prevalence of peri-implant diseases, as well as risks for peri-implant mucositis and to evaluate measures for the management of peri-implant mucositis. METHODS Discussions were informed by four systematic reviews on the current epidemiology of peri-implant diseases, on potential risks contributing to the development of peri-implant mucositis, and on the effect of patient and of professionally administered measures to manage peri-implant mucositis. This consensus report is based on the outcomes of these systematic reviews and on the expert opinion of the participants. RESULTS Key findings included: (i) meta-analysis estimated a weighted mean prevalence for peri-implant mucositis of 43% (CI: 32-54%) and for peri-implantitis of 22% (CI: 14-30%); (ii) bleeding on probing is considered as key clinical measure to distinguish between peri-implant health and disease; (iii) lack of regular supportive therapy in patients with peri-implant mucositis was associated with increased risk for onset of peri-implantitis; (iv) whereas plaque accumulation has been established as aetiological factor, smoking was identified as modifiable patient-related and excess cement as local risk indicator for the development of peri-implant mucositis; (v) patient-administered mechanical plaque control (with manual or powered toothbrushes) has been shown to be an effective preventive measure; (vi) professional intervention comprising oral hygiene instructions and mechanical debridement revealed a reduction in clinical signs of inflammation; (vii) adjunctive measures (antiseptics, local and systemic antibiotics, air-abrasive devices) were not found to improve the efficacy of professionally administered plaque removal in reducing clinical signs of inflammation. CONCLUSIONS Consensus was reached on recommendations for patients with dental implants and oral health care professionals with regard to the efficacy of measures to manage peri-implant mucositis. It was particularly emphasized that implant placement and prosthetic reconstructions need to allow proper personal cleaning, diagnosis by probing and professional plaque removal.

Longevity of teeth and implants - a systematic review.

The objective of this systematic review was to describe the incidence of tooth and implant loss reported in long-term studies. Prospective longitudinal studies reporting on teeth or implants survival with a follow-up period of at least 10 years were considered. Papers were excluded if the drop out rate exceeded 30% or if <70% of the initial subject sample was examined at 10 years of follow-up. Seventy publications on teeth were identified as potentially relevant for the focussed question. The analysis of the abstracts yielded 37 studies eligible for full-text analysis. The inclusion criteria were met in 11 of the publications that included in all 3015 subjects. The initial search on implant studies generated 52 publications that possibly could be included. Following the evaluation of the abstracts and full-text analysis nine publications were found to fulfil the inclusion criteria. The nine studies included 476 subjects. The incidence of tooth loss among subjects with a follow-up period of 10-30 years varied from 1.3% to 5% in the majority of studies, while in two epidemiological studies on rural Chinese populations the incidences of tooth loss were 14% and 20%. The percentage of implants reported as lost during the follow-up period varied between 1% and 18%. In clinically well-maintained patients, the loss rate at teeth was lower than that at implant. Bone level changes appeared to be small at teeth as well as at implants in well-maintained patients. Comparisons of the longevity at teeth and dental implants are difficult due to heterogeneity among the studies.

Clinical research of peri‐implant diseases – quality of reporting, case definitions and methods to study incidence, prevalence and risk factors of peri‐implant diseases

AIM To review the quality of reporting and the methodology of clinical research on the incidence, prevalence and risk factors of peri-implant diseases. METHODS A MEDLINE search was conducted for cross-sectional, case-control and prospective longitudinal studies reporting on peri-implant diseases. To evaluate the quality of reporting of the selected studies the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) checklist was utilized. RESULTS The search provided 306 titles and abstracts, out of which 40 were selected for full-text analysis. Finally, 16 studies were included out of which five assessed prevalence and only two the incidence of peri-implant diseases. 13 articles studied risk indicators for peri-implant diseases. None of the scrutinized articles adhered fully to the STROBE criteria. The large majority of articles did not (i) clearly state the applied study design, (ii) describe any effort to address potential sources of bias, (iii) explain how missing data were addressed, (iv) perform any kind of sensitivity analysis, (v) indicate the number of participants with missing data for each variable of interest. CONCLUSION Collectively, the findings of this review indicate a need for improved reporting of epidemiological studies on peri-implant diseases.

Effectiveness of Implant Therapy Analyzed in a Swedish Population Early and Late Implant Loss

Treatment outcomes in implant dentistry have been mainly assessed as implant survival rates in small, selected patient groups of specialist or university clinical settings. This study reports on loss of dental implants assessed in a large and randomly selected patient sample. The results were aimed at representing evaluation of effectiveness of implant dentistry. Using the national data register of the Swedish Social Insurance Agency, 4,716 patients were randomly selected. All had been provided with implant-supported restorative therapy in 2003. Patient files of 2,765 patients (11,311 implants) were collected from more than 800 clinicians. Information on patients, treatment procedures, and outcomes related to the implant-supported restorative therapy was extracted from the files. In total, 596 of the 2,765 subjects, provided with 2,367 implants, attended a clinical examination 9 y after therapy. Implant loss that occurred prior to connection of the supraconstruction was scored as an early implant loss, while later occurring loss was considered late implant loss. Early implant loss occurred in 4.4% of patients (1.4% of implants), while 4.2% of the patients who were examined 9 y after therapy presented with late implant loss (2.0% of implants). Overall, 7.6% of the patients had lost at least 1 implant. Multilevel analysis revealed higher odds ratios for early implant loss among smokers and patients with an initial diagnosis of periodontitis. Implants shorter than 10 mm and representing certain brands also showed higher odds ratios for early implant loss. Implant brand also influenced late implant loss. Implant loss is not an uncommon event, and patient and implant characteristics influence outcomes (ClinicalTrials.gov NCT01825772).

Severity and pattern of peri-implantitis-associated bone loss

OBJECTIVE The purpose of the present study was to describe the severity and pattern of peri-implantitis-associated bone loss. MATERIAL AND METHODS Intra-oral radiographs from 182 subjects were analysed. Bone-level measurements were performed in 419 implants with a history of bone loss. All radiographs obtained in the interval from the 1-year follow-up to the end-point examination (5-23 years) were analysed. The amount of bone loss that occurred from 1 year after prosthesis insertion was assessed and the pattern of bone loss was evaluated. RESULTS The average bone loss after the first year of function was 1.68 mm and 32% of the implants demonstrated bone loss > or =2 mm. The multilevel model revealed that the bone loss showed a non-linear pattern and that the rate of bone loss increased over time. The model also revealed that the pattern of peri-implantitis associated bone loss was similar within the same subject. CONCLUSION It is suggested that peri-implantitis-associated bone loss varies between subjects and is, in most cases, characterized by a non-linear progression, with the rate of loss increasing over time.

Implant‐supported fixed cantilever prosthesis in partially edentulous jaws: a cohort prospective study

BACKGROUND Reconstructive procedures present a higher rate of biological costs due to the necessity of bone harvest and grafts, use of semipermeable barriers etc. On the hand, implant supported cantilever prostheses could allow a simpler rehabilitation procedure. AIMS The aim of the present study was to assess the clinical outcome of patients treated with implant-supported fixed partial dentures (FPD) with cantilever after a mean follow-up time of 8 years. MATERIAL AND METHODS The study included 45 consecutive partially edentulous patients treated between January 1994 and August 2006 with 59 partial cantilever fixed prostheses supported by 116 ITI implants. The primary outcome variable considered was the presence of complications at the subject and bridge level; the secondary outcome variable was marginal bone loss (MBL). The frequency of complications was analyzed according to cantilever location and opposite dentition and tested by Fishers exact test. A multilevel regression model was constructed to analyze the factors influencing MBL with three levels: subject as the highest, and then implant and site. During the follow-up period, 11 implants showed a bone loss exceeding the limit for success, out of which two implants showed an infection of the peri-implant tissue. RESULTS After an average observation of 8.2 years of cantilever prostheses loading, the implant success and survival rates were 90.5% and 100%, respectively. Besides, the prosthetic success and survival rate were 57.7% and 100%, respectively. DISCUSSION None of the predictors included in the multilevel model presented a significant impact on the bone loss between baseline and the follow-up examination. CONCLUSIONS The authors concluded that the prognosis of implant-supported FPDs and marginal bone loss at implants were not influenced by the position or the length of the cantilever, the location of the bridge and type of opposite dentition. Implant-supported fixed cantilever prosthesis can be considered a suitable treatment choice.

Peri-implantitis – onset and pattern of progression

BACKGROUND While information on the prevalence of peri-implantitis is available, data describing onset and progression of the disease are limited. MATERIAL & METHODS A 9-year follow-up examination of 596 randomly selected implant-carrying individuals identified 62 patients with moderate/severe peri-implantitis. Longitudinal assessments of peri-implant marginal bone levels were used to construct a statistical model with bone loss as the dependent variable. A multilevel growth model estimated the pattern of bone loss for each implant/patient. Onset of peri-implantitis was determined by evaluating the cumulative percentage of implants/patients presenting with estimated bone loss at each year following prosthesis delivery. RESULTS The analysis showed a non-linear, accelerating pattern of bone loss at the 105 affected implants. The onset of peri-implantitis occurred early, and 52% and 66% of implants presented with bone loss of >0.5 mm at years 2 and 3 respectively. A total of 70% and 81% of subjects presented with ≥1 implants with bone loss of >0.5 mm at years 2 and 3 respectively. CONCLUSIONS It is suggested that peri-implantitis progresses in a non-linear, accelerating pattern and that, for the majority of cases, the onset occurs within 3 years of function.

Implant‐supported mandibular overdentures: a cross‐sectional study

OBJECTIVE The aim of this cross-sectional study was to determine the clinical outcome and patient satisfaction in subjects treated with mandibular overdentures supported by two implants. MATERIAL AND METHODS One hundred and fifty-nine patients, who received restorative therapy in the edentulous mandible consisting of a bar-retained overdenture supported by two osseointegrated implants in a private clinic in Italy, were recalled for a clinical and radiographic examination. One hundred and forty-one subjects with 280 implants attended the examination. The average follow-up time was 3.9 years. The radiographic examination included assessments of the distance between the implant margin and the most coronal position of bone-to-implant contact at the mesial and distal aspects of each implant. A questionnaire regarding comfort, satisfaction with the treatment, aesthetics, speaking capacity and efficiency in chewing was obtained from each subject. Biological and technical complications were recorded and the number of visits due to complications between the delivery of the prostheses and the re-examination was determined. RESULTS The results from the examination revealed that the number of lost implants was small and the average marginal bone level around the implants was 0.67 mm apical of the implant margin. The most frequently observed complication was hyperplasia of the mucosal tissue under the bar construction. Few patients experienced loosening of retention. The vast majority of patients reported to be satisfied in relation to the restorative therapy from both functional and aesthetic points of view. CONCLUSION Patients with edentulous mandibles may be successfully rehabilitated by means of two implants supporting a bar-retained overdenture.