Marginal Bone Maintenance Research Articles

Marginal Bone Maintenance and Different Prosthetic Emergence Angles: A 3-Year Retrospective Study.

The aim of the present retrospective study was to assess marginal bone changes around implants restored with different prosthetic emergence profile angles. Patients were treated with implants supporting fixed dentures and were followed for 3 years. Marginal bone levels (MBL) measured at the prosthesis installation (t0) and at the 3-year follow-up visit (t1) were considered. The MBL change from t0 to t1 was investigated. Two groups were considered: Group 1 for restorations with an angle between implant axis and prosthetic emergence profile >30°, and Group 2 for those with an angle ≤30°, respectively. Moreover, peri-implant soft tissue parameters, such as the modified bleeding index (MBI) and plaque index (PI) were assessed. Seventy-four patients were included in the analysis and a total of 312 implants were examined. The mean EA in groups 1 and 2 was 45 ± 4 and 22 ± 7 degrees, respectively. The mean marginal bone level change (MBL change) of 0.06 ± 0.09 mm and 0.06 ± 0.10 mm were, respectively, in groups 1 and 2. The difference in the MBL change between the two groups was not statistically significant (p = 0.969). The MBL change does not seem to be influenced by the emergence angle for implants with a stable internal conical connection and platform-switching of the abutment diameter.

Marginal Bone and Keratinized Mucosa Alterations Around Sloped Implants Placed in Healed Sloped Crests: A Long-Term Cohort Study.

To improve the adaptation to bone level discrepancies of sloped alveolar crests, an implant with a sloped implant-abutment interface has been developed. In a previously reported international multicenter study, 65 sloped implants replaced single teeth with a buccolingual bone level discrepancy at least 3 months after tooth loss. The present study reports the long-term outcomes of one study center and also evaluates marginal bone and keratinized mucosa alterations around sloped implants in healed, sloped crests in a long-term follow-up. Implant survival, marginal bone levels, and buccal bone dimensions in relation to the implant shoulder level (assessed by periapical radiographs and CBCT), width of keratinized mucosa, and probing depths were observed. Two patients did not present for follow-up examinations. No implants were lost. The remaining 13 implants were followed for a mean period of 123 months. Mean marginal bone levels were maintained slightly coronal to implant shoulder level at the interproximal (0.13 mm) and the buccal aspects (0.57 mm). The width of keratinized mucosa improved significantly from delivery (1.85 mm) to the 1-year follow-up (3.39 mm) and was thereafter unchanged. Placing implants with a sloped shoulder in a healed crest with lingual-buccal bone level discrepancy resulted in circumferential marginal bone maintenance and improved width of the keratinized mucosa.

Survival Rates of Splinted and Nonsplinted Prostheses Supported by Short Dental Implants (≤8.5 mm): A Systematic Review and Meta-Analysis.

To evaluate and compare the implant survival rates, marginal bone loss, and mechanical complications of prostheses supported by splinted and nonsplinted short implants (≤8.5 mm). Electronic database (MEDLINE, CENTRAL, Web of Science, and EMBASE) and manual searches up to May 2021 were conducted to identify studies comparing splinted and nonsplinted short implants (≤8.5 mm). The primary outcome was implant survival rate. Secondary outcomes were marginal bone loss and mechanical complications. The quality of included studies and risk-of-bias were assessed according to the Newcastle-Ottawa Scale. A random-effects model was used to analyze the data. Twelve studies fulfilled the inclusion criteria and featured 1506 short implants (596 nonsplinted and 910 splinted) with a follow-up time ranging from 1 to 16 years. Quantitative analysis found no statistically significant differences between splinted and nonsplinted short implants (≤8.5 mm) for survival rate (RR= 0.98; 95% CI 0.96, 1.01; p = 0.26)) and marginal bone loss (SMD = -0.08; 95% CI- 0.23, 0.07; p = 0.28). Veneer chipping, abutment screw breakage, screw loosening, and loss of retention were reported in the selected studies as common complications. However, no statistically significant difference was found between splinted and nonsplinted short implants (RR = 0.56; 95% CI 0.20, 1.54; p = 0.26). Within the limitations of the present meta-analysis, it might be concluded that splinted short implants (≤8.5 mm) do not present superior performance in survival rate, marginal bone maintenance and prevention of mechanical complications compared with single-unit prostheses.

Periimplant bone changes in different abutment heights and insertion timing in posterior mandibular areas: Three-year results from a randomized prospective clinical trial.

To compare the influence of the abutment height and its insertion timing on the marginal bone change (MBC) variation of implants placed at posterior mandibular partial edentulous areas in a medium follow-up period. This randomized clinical trial (RCT) comprised a sample of patients with posterior mandibular edentulous areas, treated with at least two implants and distributed into three groups: implants connected to a 2mm height abutment during the surgical stage (Group A); implants connected to a 1mm height abutment during the surgical stage (Group B); and implants connected to a 2mm height abutment after 2months (Group C). Clinical and radiographic measurements were performed during a 36-month period (T4). The MBC was set as the main variable in study. Statistical significance was set at 0.05. A total of 29 subjects and 59 implants were enrolled in this study. A mean MBC of 0.35±0.46mm, 0.60±0.81mm, and 0.71±0.90mm was computed for groups A, B and C, respectively, at T4. Significant differences were found between groups A and C in terms of MBC variation after 3years of treatment (p=.048). Multiple linear regression analysis showed a significant influence of the first-year MBC and the abutment insertion timing has independent predictor variables for the MBC assessed at T4. The installation of 2-mm prosthetic abutments, at the time of implant placement, in areas with limited keratinized mucosa presents as a favorable treatment option in terms of periimplant marginal bone maintenance.

Marginal bone maintenance around implants placed in subcrestal level: a 2 to 9 years retrospective study

Marginal bone maintenance around implants placed in subcrestal level: a 2 to 9 years retrospective study

Immediate fixed rehabilitation supported by pterygoid implants for participants with severe maxillary atrophy: 1-Year postloading results from a prospective cohort study

Statement of problemFew investigations concerning the use of pterygoid implants have reported reproducible and consistent data, making survival data controversial. PurposeThe purpose of this clinical study was to investigate the 1-year survival and success rates of pterygoid implants and prostheses in participants affected by severe atrophy of the posterior maxilla requiring a complete-arch immediate fixed prosthesis. Material and methodsFifteen participants, either completely edentulous or with failing dentition in the maxillary arch and with severe atrophy of the posterior maxilla, were enrolled in the study. All participants underwent prosthodontic rehabilitation after implant placement in both the anterior maxilla areas and the pterygoid regions. The survival data of the implants were evaluated at the time of abutment connection by means of a mobility test for each implant. After placement of the prostheses, survival was assessed by means of marginal bone maintenance as assessed by panoramic radiographs and the absence of pain or symptoms of infection. The t test was used for evaluating the difference in age between men and women (α=.05). Correlations between categorical variables (Fisher exact test) were used to evaluate the possible association between the number of implants and both the age and presence of comorbidities (α=.05). ResultsDuring the 1-year follow-up, high prosthesis stability and no implant loss were observed for all participants. In addition, participants did not report any pain or paresthesia. No peri-implant radiolucency was detected in the panoramic radiographs. Survival and success rates in the follow-up period were 100%. ConclusionsThe present study supports the conclusion that pterygoid implants have a high success rate with minimal or no complications.

One‐year clinical study evaluating the fast loading protocol – Immediate provisionalization and delivery of definitive prosthesis within 8 weeks

Background One requirement for the predictability of implant treatment with immediate loading protocols is high primary stability. Resonance frequency analysis (RFA) and insertion torque (IT) has been proposed to assess this stability with a quantitative method. Aim/Hypothesis To investigate the clinical outcome, marginal bone maintenance and implant survival for implant treatment using the fast loading protocol which include immediate provisionalization and early delivery of the definitive prosthesis. Material and Methods Of 25 patients were treated with 48 Neoss ProActive Tapered implants placed in both maxilla and mandible in healed bone as well as in fresh extraction sockets. Minimum primary stability, (IT > 35 ncm and RFA > 60), for all single implants was established before subjected to immediate (within 48 hours), non-functional, load using screw-retained temporary restorations (single or maximum 2 splinted implants with 2–3 teeth units). Definitive prostheses were delivered within 6–8 weeks from implant placement, based on RFA measurements during early healing phase. IT, RFA, intraoral radiographs, and impressions of implant positions were registered at implant placement. During clinical follow-up RFA was measured at 2, 4, 6 weeks and 6 months from implant placement. Marginal bone level measurements were performed from intraoral radiographs taken at implant placement, 6-, and 12-month follow-up visits. Results 48 implants were subjected to the fast loading protocol. IT was over 40 Ncm for 46 implants. Two implants with IT < 35 Ncm were both splinted to another implant with IT > 50 Ncm, tightening the retention screw with low forces. No implants were lost during the observation period, giving an implant survival rate of 100%. Mean RFA measurements remained stable without any decrease during the initial healing phase, 78.3 ± 4.0 in the mesiodistal direction and 77.6 ± 4.4 in the buccolingual direction at placement and 81.3 ± 3.7 and 80.8 ± 3.6 respectively at 6 months. Radiographic readings showed that at placement the implant platform was at bone level (+0.13 mm). Mean marginal bone remodeling was −0.47 ± 0.38 mm from implant placement to 1 year, −0.49 ± 0.38 mm from implant placement to 6 months, and only 0.01 ± 0.28 mm between 6 to 12 months follow-up. No significant differences could be found for marginal bone remodeling between implants placed in healed bone and those placed in fresh extraction sockets. Conclusion and Clinical Implications Achieving good primary stability (IT of 40 Ncm) with maintained implant stability during initial healing phase can guarantee predictable clinical outcome for patients subjected to a fast loading protocol. Fast loading showed no significant differences in marginal bone loss in the first year of follow-up as compared to other studies investigating the same implant type but followed different surgical and prosthetic protocols.

Single molar replacement immediately loaded with final crown through Straumann BLX and chairside digital workflow – One tooth one time technique

Background Immediate implant loading is a valid treatment and usually with an immediate provisionalization without occlusal contact. Implant's modifications of topography and roughness, thread design and dimensions influence the functional bone-to-implant area. The Straumann® BLX is a fully tapered bone level implant that provides optimum primary stability, osseointegration with enhanced bone-to-implant contact and marginal bone maintenance properties, turning it a good choice for immediate loading. Aim/Hypothesis This study brings a case series treated with a technique described as One Tooth One Time (1T1T), consisting in the replacement of missing posterior teeth using the new Straumann® BLX Implant system and digital workflow for the rehabilitation of the cases with an immediate definitive prosthesis. Material and Methods This series of cases gathered, from a private clinic in Lisbon, Portugal, eight patients were selected and sought routine treatment for the replacement of a missing molar with a dental implant. The study only collected cases of patients who presented an absent first molar tooth that could be rehabilitated with a dental implant. The immediate prosthesis would be placed in functional occlusion to the opposing dentition with the same principles of a final restoration placed on a single osseointegrated implant. The same surgeon performed all the surgical procedures in October 2018 and the same prosthodontic practice for the final prosthesis. The width of the osteotomy was defined following clinical evaluation of bone density since the drilling sequence in this type of implant depends on the quality of bone. The rehabilitation design was made based on the STL file from the digital scan with the scan body screwed into the implants and the final crown digitally produced was planned virtually. Results This case series of single molars reveals a new approach, the 1T1T technique, with the use of Straumann® BLX implants, that allows increased primary stability and enhanced bone-to-implant contact, to immediately place a definitive crown. The first requirement is that the implant achieve primary stability, and then a crown can be manufactured with a digital workflow, so it is critical to select an implant design that will ensure primary stability. Digital planning and processing make the dental implant treatment option much less burdensome and easier to deliver for the dental implant team and patient, thus improving global acceptability and utilization. The Straumann® BLX is a fully-tapered implant introduced to optimize primary stability, even in low density or compromised bone situations, to simplify the rehabilitation workflow and have predictable outcomes, turning it a good choice for immediate extraction, immediate placement and loading cases. Conclusion and Clinical Implications This digital implant dentistry protocol could lead to more predictable results and a more efficient workflow, which will help control costs and save time for the patient and the dental team. The 1T1T technique performed on the cases collected, presenting a missing first molar treated with implants and restored with the definitive crown. This technique which has been demonstrated predictable in 2016 using a different implant appears to be applicable in daily practice with Straumann BLX system.

Platform switching technique and crestal bone loss around the dental implants: A systematic review

Background:The overall success of dental implants depends on the crestal bone support around the implants. During the initial years of dental implant placement, the bone loss around the implants determines the success rate of treatment. Platform switching (PLS) concept preserves the crestal bone loss, and this approach should be applied clinically for the overall success of dental implants.Purpose:The purpose of this study is to discuss the literature dealing with the concept of PLS concept and preservation of marginal bone, the mechanism by which it contributes to maintenance of marginal bone, its clinical applications, advantages, and disadvantages, to assess its survival rates.Materials and Methods:PubMed and Google Scholar search was done to find out the studies involving PLS concept from 2005 to 2017. Data were analyzed using SPSS statistical software.Results:Literature search revealed studies involving concepts of PLS, comparison of platform-switched and nonplatform-switched implants, case reports on PLS, and studies with histological and finite element analyses regarding PLS.Conclusion:PLS helps preserve crestal bone around the implants, and this concept should be followed when clinical situations in implant placement permit.

Influence of different implant geometry in clinical longevity and maintenance of marginal bone: a systematic review

Influence of different implant geometry in clinical longevity and maintenance of marginal bone: a systematic review

Influence of Different Implant Geometry in Clinical Longevity and Maintenance of Marginal Bone: A Systematic Review.

To assess, through a systematic review, the influence of different implant geometries on clinical longevity and maintenance of marginal bone tissue. An electronic search was conducted in MEDLINE, Scopus, and Web of Science databases, limited to studies written in English from 1996 to 2017 using specific search strategies. Only randomized controlled trials (RCTs) that compared dental implants and their geometries were included. Two reviewers independently selected studies, extracted data, and assessed the risk of bias of included studies. From the 4006 references identified by the search, 24 were considered eligible for full-text analysis, after which 10 studies were included in this review. A similar behavior of marginal bone loss between tapered and cylindrical geometries was observed; however, implants that had micro-threads in the neck presented a slight decrease of marginal bone loss compared to implants with straight or smooth neck. Success and survival rates were high, with cylindrical implants presenting higher success and survival rates than tapered ones. Implant geometry seems to have little influence on marginal bone loss (MBL) and survival and success rates after 1year of implant placement; however, the evidence in this systematic review was classified as very low due to limitations such as study design, sample size, and publication bias. Thus, more well-designed RCTs should be conducted to provide evidence regarding the influence of implant geometry on MBL and survival and success rates after 1year of implant placement.

Does crown/implant ratio influence the survival and marginal bone level of short single implants in the mandibular molar? A preliminary investigation consisting of 12 patients.

Crown/implant (C/I) ratio has been proven to not affect the survival of the implants; however, it is also a fact that no evidence exists with regard to the use of single short implants in the mandibular molar. The aim of this study was to determine whether the crown/implant ratios of single implant-supported fixed restorations on implants of 6-8 mm in the mandibular molar have an impact on the implant survival and marginal bone maintenance. Twelve short dental implants (6-8 mm) were installed and restored with single crowns, loaded after 3 months of healing. The restorations were divided according to crown-to-implant ratio into two groups: Group 1: C/I < 2.0 and Group 2: C/I ≧ 2.0. Alveolar bone loss was measured using CBCT scan, taken at the implant placement and after 12 months follow-up from loading. Reduced implant/crown ratio shown no statistic significant differences on implant survival and the alveolar bone level compared with recommended implant/crown ratio. Within the limitation of this study, it can be concluded that reduced C/I ratio could be used as a substitute for recommended C/I ratio in severely mandibular atrophic residual alveolar ridges.

Denture-Related Biomechanical Factors for Fixed Partial Dentures Retained on Short Dental Implants.

Prosthodontically driven biomechanical considerations are essential for longterm successful outcomes in dental implant therapy. Correct protocols seek to preclude potential consequences associated with functional and parafunctional occlusal overload such as screw loosening, component fracture, compromised marginal bone maintenance, and the integrity of the induced osseointegration response. Other concerns also need to be addressed, more especially when other implants are selected, for example: bridge insertion torque (BIT) in cases of immediate loading, cantilever length-anteroposterior spread ratio (CL-AP), overall crown-to-implant ratio (oCIR), total bone-to-implant surface area (tBICA), and the status of the opposing dentition. In spite of promising clinical results, evidence-based clinical protocols demand that such biomechanical limits still need to be determined.

Eight-year clinical and radiologic results of maxillary and mandibular implant-retained bar overdentures carried out on oxidized (TiUnite™) replace select implants placed in regenerated bone: a clinical case.

This article describes the clinical and radiologic long-term results of a healthy, nonsmoker women aged 62 at the time of treatment, with severely resorbed edentulous jaws in which bar and clip supported complete dentures were delivered in both jaws and followed for 8 years after prosthesis delivery. The patient had been edentulous in both arches since she was 50 years old. Treatment included the placement of four mandibular implants with maximum spacing anterior to the mandibular nerve, and four maxillary implants anterior to sinus wall without tilting the posterior implants, because of the insufficient bone quantity necessary to angulate implants. Guided bone regeneration was required in the maxilla, due to a bone atrophy that limited the placement of conventional dental implants. After 4 months, a second-stage surgery was performed, and after 1 month of healing time the patient received definitive restorations. Implant survival rate, patient satisfaction, marginal bone maintenance, and soft tissue conditions at the modified titanium surface of the dental implants were evaluated after 8 years of function. A multifactorial approach, clinician-patient relationship, and vigilant maintenance of oral hygiene were needed in order to ensure an optimal treatment and a long-term successful result. Positive results regarding bone maintenance in the long-term perspective, also on regenerated bone, were observed using implants with implant-retained bar overdentures, when adequate levels of oral hygiene and prosthodontic adjustments are maintained.

Platform Switching: A Review

The long-term success of an implant depends on the stability of bone support for the implant. Most crestal bone loss occurs in the first year of implant placement. Platform switching is an approach which can be clinically applied to preserve the crestal bone. The purpose of this review is to discuss the literature dealing with the platform switching concept to preserve the crestal bone, the mechanism by which it contributes to maintenance of marginal bone, its clinical applications, advantages and disadvantages, in order to assess its survival rates.

Radiographic evaluation of marginal bone maintenance around tissue level implant and bone level implant: a randomised controlled trial. A 1‐year follow‐up

The etiologic factors associated with crestal bone loss have not been comprehensively clarified. Several theories exist as to the reason for the observed changes in crestal bone height following implant restoration. In the 1990s, the wide-diameter implants were commercially introduced. Initially, the implants were restored with standard-diameter abutments because of lack of matching prosthetic components. Long-term radiographic follow-up of these 'platform-switched' restored wide-diameter dental implants has demonstrated a smaller-than-expected vertical change in the crestal bone height around these implants that is typically observed around implants restored conventionally with prosthetic components of matching diameters. The aim of this randomised controlled study was to assess radiographically marginal bone level alterations in implants restored according to the platform-switching concept compared with traditionally restored implants. Fifty-four subjects to participate in this randomised controlled study were selected. Two groups were assigned at random: control group (56 implants were restored with standard matching-diameter abutments) and test group (58 implants were restored with medialised abutments). X-ray explorations were taken for peri-implant bone level at the minute the last cementing of the prosthesis and at 1-year follow-up. NHI Image was used to digitally process and manipulate the radiographic images and perform the measurements. Mean of bone loss with platform-switching implants was -0·01 mm, and the mean of bone loss with standard platform implant was 0·42 mm. Outcomes of this study indicated that the platform-switching design could preserve the crestal bone levels to 1-year follow-up. There was a statistically significant difference in marginal bone loss.

Platform switching: An answer to crestal bone loss

Background: The long-term success of an implant depends on the stability of bone support for the implant. Most crestal bone loss occurs in the first year of implant placement. Platform switching is an approach which can be clinically applied to preserve the crestal bone. Purpose: The purpose of this review is to discuss the literature dealing with the platform switching concept to preserve the crestal bone, the mechanism by which it contributes to maintenance of marginal bone, its clinical applications, advantages and disadvantages, in order to assess its survival rates. Materials and Methods: PubMed and Google Scholar were used to find studies involving platform switching concept from 2005 up to October 2009. Results: Literature search revealed studies involving concepts of platform switching, comparison of platform-switched and non-platform-switched implants, case reports on platform switching and studies with histological and finite element analyses regarding platform switching. Conclusion: Platform switching helps preserve crestal bone around the implants and this concept should be followed when clinical situations in implant placement permit.

Marginal bone levels at single tooth implants with a conical fixture design. The influence of surface macro- and microstructure.

The concept of a conical implant design to accommodate single tooth replacement, has previously been shown to result in excessive bone loss, around the machined titanium conical collar, usually down to the 1st thread. This unusually aggressive loss of bone was shown to occur within a short period of time, post loading, with greater than 3 mm of bone loss occurring within the 1st 6 months to 1 year. The influence of implant design, surface texture and microleakage have all been highlighted as a potential cause. A modification of the surface structure, both at the macroscopic and microscopic level, as well as an altered fixture-abutment interface design has resulted in the maintenance of marginal bone around a single tooth titanium implant with a similar conical design. The radiographic follow-up of 33 implants loaded for up to 4 years, has revealed, by comparison, a most favourable maintenance of marginal bone around the conical collar, with a mean marginal bone loss of 0.32 mm mesially and 0.34 mm distally for the whole group. The cumulative mean marginal bone loss mesially and distally is 0.42 mm and 0.40 mm from 1 to 2 years, 0.54 mm and 0.43 mm from 2 to 3 years, 0.51 mm and 0.24 mm from 3 to 4 years, and 0.62 mm and 0.60 mm for implants past their 4 year recall.