Marginal Bone Level Alterations Research Articles

One-Piece Mini Dental Implant-Retained Mandibular Overdentures: 10-Year Clinical and Radiological Outcomes of a Non-Comparative Longitudinal Observational Study.

This study presents the first 10-year follow-up investigation of the implant survival and peri-implant outcomes of one-piece mini dental implants (MDIs) retaining mandibular implant overdentures (IODs), including marginal bone level alterations (ΔMBLs), clinical peri-implant parameters, and complications. Twenty participants with horizontally atrophied mandibles received complete dentures and four MDIs (diameter 1.8 mm) at baseline. The dentures were converted into IODs with O-ring attachments. The 10-year follow-up comprised a radiological assessment of ΔMBLs, peri-implant parameters, as well as biological and technical complications. Results from a 10-year follow-up of 14 participants showed a 100% implant survival rate for all 56 implants. The mean ΔMBL after 10 years was -1.12 ± 0.80 mm, with 49 implants classified as successful (ΔMBL < 2 mm) and 7 implants with satisfactory survival (ΔMBL 2-4 mm). Time after implant placement significantly influenced ΔMBL, with stable MBLs after 5 years. The prosthetic survival rate after 10 years was 93%. ΔMBLs were not influenced by implant position or gender but were significantly smaller in subjects older than 65 years. Conclusively, one-piece MDIs with O-ring attachments offer a reliable treatment option for horizontally atrophied mandibles after 10 years, with high implant and prosthetic survival rates, potentially benefiting from advanced age regarding peri-implant bone stability.

Synergistic effect of nicotine on different implant platform design in implant-assisted mandibular overdenture, 1- Year clinical and radiographic study

Background In implant therapy, peri-implant bone loss has been noticed mainly in the first year after prosthesis insertion. This bone loss can sometimes jeopardize the outcome of the treatment. Different implant platform designs are widely used in implant dentistry; however, its influence on the health of the surrounding soft tissues and marginal bone level alterations in implant-assisted overdentures particularly in smoker patients, remains inconclusive. The purpose of this study will be to evaluate the effect of nicotine on different implant platform designs in complete mandibular implant-assisted overdenture patient. Materials and methods Ten male smoker patients were selected for this study. Split mouth study design will be used in this study where, Group I represented the right side of the patients’ mandibular interforamenal region restored with platform-switched implant and Group II represented the left side of the patients’ mandibular interforamenal region restored with nonplatform swithched implants. The patients received complete mandibular assisted overdenture with O-ring attachment. Clinical and Radiographic evaluations were carried out for every patient at regular recall visits at the time of insertion, 6, and 12 months. At the end of the study, all implants of both groups were successfully osseointegrated. The data of this study were collected, tabulated, and statistically analyzed by IBM-SPSS statistics software (Independent T-test Samples). Result There were insignificant differences between both groups regarding plaque index (PI), bleeding index (BI), pocket depth (PD) and stability of the implants. Radiographically, there were significant differences in the mandibular bone density at the bone implant interface and marginal bone loss between both groups. Group I implant represented less marginal bone loss and higher bone density than Group II implants. Conclusion In smoker patient Platform-Switched dental implant is the implant of choice to control marginal bone loss around implants.

Comparative evaluation of hard and soft tissue parameters by using short implants and standard long implants with sinus lift for prosthetic rehabilitation of posterior maxilla.

The objective is to compare and evaluate the hard and soft tissue parameters by using short and standard long implants with sinus lifting in the posterior maxilla. Eleven patients with complaints of missing upper back teeth were enrolled in the study for implant-supported rehabilitation and were categorized into two groups: Group long (GL): longer implant (>8 mm) placement, preceded by Sinus Augmentation. Group short (GS): short implant (≤8 mm) placement, without sinus augmentation. The primary outcome measured was cumulative survival rate (CSR) in the compromised partial edentulous posterior maxilla. Secondary outcomes measured were implant stability (IS), marginal bone level alterations (MBL), pocket probing depth (PPD), crown-to-implant ratio, and any complications. The difference in CSR between the groups was not statistically significant (P = 0.317). High stability was achieved immediately after the placement of the implants, in both groups (GS: 64 ± 4.07, GL: 65.58 ± 9.75); this difference in the mean ISQ (IS quotients) values was not found to be statistically significant at implant placement (P = 0.7). The mean MBL reported in the study at the end of 12 months of prosthesis function was - 0.762 ± 0.48 mm and - 0.7 ± 0.34 mm for GS and GL, respectively. The mean PPD measurements in GS and GL groups were 1.917 ± 0.68 mm and 1.833 ± 0.38 mm, respectively, and it was not statistically significant (P = 0.8). Within the limitations of the present study, the obtained results indicate that short implants provided a similar clinical and radiographic performance compared to long implants placed in combination with a sinus augmentation procedure (lateral window) up to 12 months after prosthetic loading.

Soft Loading Protocol of Short Strategic Implants in Posterior Mandibles Supporting Removable Bilateral Free-End Prostheses: 1-year Results of a Prospective Cohort Study.

To evaluate 1-year survival and success rates of 6-mm short implants placed in mandibular molar sites with two different abutments (dome/ball) retaining existing removable partial dentures (RPDs). In 19 patients, 38 implants of 6-mm length were placed bilaterally. After 4 months, each participant received the dome abutment, which 2 months later was exchanged with the ball abutment. Clinical data were recorded at abutment connection (4 months postsurgery) and at 6 and 12 months postsurgery, including probing depth, bleeding on probing, presence of plaque, and standardized radiographs. Implant success was assessed using the following criteria: presence of pain, mobility, radiographic bone loss, probing depth, and the presence of exudate. For descriptive analyses, mean and SD values were calculated. Paired sample t tests and linear regressions with a significance level of α < .05 were applied to analyze the evolution of peri-implant parameters and the influence of implant placement depth. The overall mean marginal bone level alteration (DMBL) was 1.05 ± 0.69 mm. A statistically significant marginal bone loss over time was observed at the mesial and distal aspects of all implants (P < .05). The implant survival rate was 100%. No implants showed pain, exudate, mobility, or probing depth > 7 mm. Three implants were classified as having satisfactory survival due to a DMBL > 2 mm (resulting success rate: 92.1%). No influence of implant placement depth was found. These short-term results suggest that short implants can be used in mandibular molar sites for additional posterior support of free-end RPDs. However, in individual cases, DMBL > 2 mm may occur.

An open, randomised, multi-centre study, comparing straight and tapered apex implants design, in partially and totally edentulous maxillae

The design of the commercially available implant OsseoSpeed® (control) was changed to a tapered apex with a smaller apical diameter; OsseoSpeed® TX (test). Objective The present study evaluated the clinical outcome of marginal bone level as primary outcome, and cumulative implant survival rate, primary stability and condition of the peri-implant mucosa as secondary outcomes, one year after loading. Material and methods 92 subjects (150 implants, ten centres), with partially or totally edentate maxillae were randomized to receive either test or control implants. One to six implants were placed in each subject using a one-stage surgical procedure. Subjects received a permanent prosthesis 10–12 weeks after implant placement and were followed for one year Results 47 subjects in the test group received 82 implants and 45 subjects in the control group received 68 implants. Marginal bone level alterations from loading to 1-year follow-up was −0.02 × 0.41 mm (mean × SD) and −0.03 × 0.38 mm (mean × SD) for the test and the control group, respectively, indicating no difference between the groups. Non-inferiority was declared as confidence interval for the difference between control and test implants was no worse than 0.5 mm. The CSR was 98.8% in the test group and 100% in the control group, with no statistically significant difference between the groups. Conclusions Change of the apical design of a commercially available implant showed no significant effect on marginal bone level and CSR compared to the control implant. Missing data and many investigators may have influenced on the result. Trial registration number: NCT 01324778.

A multicenter cohort study on the association of the one-abutment one-time concept with marginal bone loss around bone level implants.

To investigate the association of the one-abutment one-time concept with marginal bone loss (MBL) around bone-level implants in relation to other factors. Records from patients treated by four experienced implant surgeons between January 2016 and July 2019 were scrutinized. Subjects treated with two bone-level implant types with varying machined collar (subgroups: 0.5 and 0.8mm) were considered, receiving a healing abutment (HA cohort) or a permanent abutment at the time of surgery (OT cohort). The primary outcome was MBL registered at 3months and the longest follow-up. A clustered two-part regression model for semicontinuous data was used. Data pertaining to 160 patients (92 females, mean age 54) and 344 implants (125 in HA cohort, 219 in OT cohort) were available for evaluation. Mean MBL amounted to 0.52mm (SD 0.68) after a mean follow-up of 20 (SD 9.2) months, with 33.8% of the implants showing complete bone preservation and 5.0% demonstrating >2mm MBL. OT was not related to the presence of MBL using MBL as dependent binary variable (0: no MBL; 1: MBL irrespective of its magnitude). However, OT significantly reduced the magnitude of MBL with 0.300mm when compared to HA (p=.023) in the cases where MBL was detected. Subgroup (p=.212), smoking (p=.789), history of periodontitis (p=.839), type of edentulism (p=.054), implant surgeon (p=.079), patient compliance (p=.617), and follow-up (p=.443) failed to show a significant association with MBL in the regression model. Ninety-eight % of the implants survived. Within the limitations of a cohort study, the one-abutment one-time concept was associated with a decrease in MBL at implant sites with bone loss. Therefore, the placement of a permanent abutment at the time of surgery seems relevant to limit marginal bone-level alterations.

Clinical outcomes and bone-level alterations around one-piece mini dental implants retaining mandibular overdentures: 5-year follow-up of a prospective cohort study.

To report on the clinical outcomes of one-piece mini dental implants (MDIs) retaining mandibular implant overdentures (IODs), including marginal bone-level alterations (ΔMBLs), clinical peri-implant parameters, and technical- and biological complications during a 5-year follow-up. The null hypothesis was that ΔMBLs would be equal in subjects older than 65years relative to younger subjects. Four 1.8-mm diameter one-piece MDIs with ball attachments were placed in the interforaminal region of 20 edentulous subjects. The existing complete dentures were converted to IODs. Standardized radiographs of each implant were taken at implant placement (baseline) and during the five-year follow-up. ΔMBLs and potential influencing factors were evaluated, and peri-implant parameters, and biological and technical complications were recorded. The implant and prosthetic survival rates were both 100%. IODs fractured in seven participants. The overall mean ΔMBL after 5years was -1.18mm (standard deviation: 0.79mm). ΔMBLs per month were most pronounced within the first 3months after implant placement. ΔMBLs were not influenced by the implant location, the presence of keratinized mucosa, or gender. However, ΔMBLs were significantly smaller in subjects older than 65years (p=.007). One-piece MDIs retaining mandibular IODs with O-ring attachments are a predictable treatment option, providing stable peri-implant bone and soft tissue conditions over a mid-term follow-up. Incorporating a metal reinforcement can prevent denture fracturing when converting a complete denture into an IOD. The presence of keratinized mucosa does not necessarily lead to decreased bone-level changes. Advanced age might be beneficial in terms of peri-implant bone stability.

Radiographic evaluation of marginal bone level alteration around narrow implants placed in narrow alveolar ridge using guided flapless surgery

Radiographic evaluation of marginal bone level alteration around narrow implants placed in narrow alveolar ridge using guided flapless surgery

Implant health and factors affecting peri-implant marginal bone alteration for implants placed in staged maxillary sinus augmentation: A 5-year prospective study.

Evaluating the extent of and the factors affecting marginal bone level (MBL) alterations and consecutively implant success and implant health for implants placed in staged maxillary sinus floor (SF) augmentation. A 5-year prospective, cohort study was conducted on 85 patients with 124 maxillary sinus augmentation procedure and 295 implants placed. Peri-implant MBL alterations (reductions) were evaluated radiographically at the first year, third year, and fifth year postloading follow-ups and were considered to patient-related risk factors (age, gender, diabetes mellitus, smoking, rheumatic disorders, and history of periodontal disease [PD]), to clinican/surgically related risk factors (membrane perforations, sinus site, and residual ridge height), to implant/prosthesis-related features (implant length, diameter, location, keratinized gingiva, and restoration gap), and to the plaque score. Additionally, implant and prostheses survival/success rate and peri-implant health (mucositis/peri-implantitis) were assessed. About 267/295 implants (drop-out:n9 pat; 28 implants: 9%) were followed for 5 years (survival/success: 99.3%/96.5%), presenting significant (P < .001) differences of MBL alterations (-1.45 ± 0.38 mm) over time. The univariate analysis demonstrated differences of MBL alterations for smokers versus nonsmokers (P = .005), for patients with versus without history of PD (P = .001), and presence versus absence of plaque (P = .041). In the 5-year multivariate analysis, MBL alteration was influenced by time (P = .001) and was related to risk factors as smoking (P = .001; odds ratio [OR] = 6.563) and history of PD (P = .015; OR = 4.450). Significant ORs for MBL alterations were also found for a restoration gap used for a full-arch dentures (P = .001; OR = 8.275) associated with reduced (≤3 mm) residual ridge height (P = .015; OR = 1.365). The overall 5 year incidence of peri-implant mucositis and peri-implantitis was 25.3% and 3.7% at implant level and 30.3% and 6.6% at patient level, respectively. Apart from the high success rate and healthy status of implant placed in staged SF seen, MBL alteration increased over time and was negatively affected predominately by patient-specific risk factors such as smoking status and previous history of periodontitis.

Clinical Outcome of Implants Placed in Staged Maxillary Sinus Augmentation Using Bovine Bone Mineral Mixed with Autogenous Bone at Three Different Ratios: A 5-Year Prospective Follow-up Study.

To evaluate the 5-year clinical outcomes for implants placed in a staged sinus floor elevation (SFE) procedure and to compare three patient groups with sinus grafts with three different ratios of bovine bone mineral (BBM) and autogenous bone (AB) mixture. A 5-year prospective cohort study was conducted on 81 patients with 119 staged SFEs non-randomly distributed to three groups based on the origin of the AB and the mixture ratio with BBM: group 1 (locally harvested AB [LHB] from osteotomy sites + BBM, ratio: 1:10), 31 patients, 37 SFEs; group 2: (LHB + intraorally harvested peripheral AB [IHPB] from retromolar/chin region + BBM, ratio: 1:4), 22 patients, 29 SFEs; and group 3 (LHB + extraorally harvested peripheral AB [EHPB] from iliac crest/tibia + BBM, ratio 1:1), 28 patients, 53 SFEs. After graft healing (5 to 7 months), 284 dental implants (group 1: 76, group 2: 61, group 3: 147 [overall: 2.3 implants/sinus]) were placed. After an additional healing period (5 to 7 months), all implants placed were functionally loaded and prospectively followed by clinical and radiographic evaluations assessing implant survival/success rate as well as peri-implant marginal bone level (MBL) alteration at 1, 3, and 5 years postloading. A total of 76/81 patients with 267/284 implants were followed for up to 5 years (dropouts: 5 patients/15 implants; implant loss = 2). The 5-year implant survival and implant success rate (group 1: 100%/98.6%; group 2: 98.3%/96.6%; group 3: 99.3%/95.7%) did not differ between the three graft mixture groups. The peri-implant marginal bone alteration (reduction) averaged over all 5 years was 1.40 ± 0.29 mm for group 1, 1.41 ± 0.22 mm for group 2, and 1.46 ± 0.46 mm for group 3 (P = .187). However, over time, a continual and significant MBL reduction (P = .045) was noted for all groups presenting peri-implant MBL changes between 1 year and 5 years of -0.17 mm (group 1), -0.12 mm (group 2), and -0.24 mm (group 3), respectively. According to the clinical results obtained, dental implants inserted in grafted (staged) SFE using a mixture of BBM with a minimal amount of AB harvested from local sites provide for similarly high 5-year implant/augmentation success rates as graft mixtures with AB harvested from peripheral intraoral or extraoral donor sites, confirming no need for additional bone harvesting.

A Prospective, Controlled, Multicenter Study to Evaluate the Clinical Outcome of Implant Treatment in Women with Osteoporosis/Osteopenia: 5-Year Results

The impact of osteoporosis on implant treatment is still a matter of debate in the scientific community, as it may possibly lead to higher failure rates. As long-term controlled trials are missing, the aim of this study was to verify the long-term outcome of implants placed in patients with systemic osteoporosis. Postmenopausal women in need of implants underwent bone mineral density measurements in hip and spine, using dual X-ray absorptiometry scans. Based on T-scores, they were divided into 2 groups: group O (osteoporosis group) with a T-score ≤−2 or group C (control group) with a T-score of ≥−1. Implants were placed in a 2-stage manner and loaded 4 to 8 wk after abutment surgery. Six months after loading and thereafter yearly, clinical and radiographical parameters were assessed. In total, 148 implants were placed in 48 patients (mean age: 67 y [range, 59−83]). Sixty-three implants were placed in 20 patients (group O) and 85 implants in 28 patients (group C). After 5 y, 117 implants (38 in group O and 79 in the group C) in 37 patients were assessed. Cumulative survival rate on an implant level was 96.5% (group O: 91.5%; group C: 100.0% [P < 0.05]) and 95.7% (group O: 89.2%; group C: 100.0% [P > 0.05]) on a patient level. The overall marginal bone-level alterations, after 5 y of loading, were −0.09 ± 0.78 mm (group O: −0.15 ± 0.50 mm; group C: −0.06 ± 0.89 mm) on an implant level and −0.09 ± 0.54 mm (group O: −0.18 ± 0.43 mm; group C: 0.06 ± 0.58 mm) on a patient level (P > 0.05). Oral implant therapy in osteoporotic patients is a reliable treatment option with comparable osseointegration rates, implant survival, and marginal bone-level alterations after 5 y of functional loading (ClinicalTrials.gov NCT00745121).

Peri-implant tissue healing at implants with different designs and placement protocols: An experimental study in dogs.

To compare the peri-implant tissue response to subcrestal or crestal placement of implants with or without "platform-switched" implant/abutment connections. On each side of the mandible in six Labrador dogs, two "platform-switched" (PS) implants and two implants with matching implant/abutment diameters (PM) were placed in a crestal or a 1.5mm subcrestal position. Sulcus formers/abutments were connected, baseline radiographs obtained and the distance between the abutment-fixture junction (A/F) and the marginal bone level (B) was determined. Five months later, radiographic and clinical examinations were repeated and biopsies were obtained and processed for histological analysis. The radiographic analysis showed that marginal bone level changes occurred during the first observation period (13weeks). PS-implants showed minor marginal bone level alterations during the full observation period (20weeks), regardless of placement depth. For PM-implants, placement had a significant impact on bone level changes; crestal placement resulted in a mean bone loss of 0.4mm and subcrestal placement in a 1.5mm bone loss. The histometric measurements resulted in a distance A/F-B of 0.6 and 0.0mm for PS implants, placed in a crestal or subcrestal position, respectively. The corresponding distance at PM-implants was 1.5mm irrespective of placement protocol. The peri-implant mucosa was thicker at subcrestally placed implants as compared to a crestal placement. Bone remodeling occurred within the early healing phase. During the full 20weeks of observation, PS-implants demonstrated significantly less crestal bone loss compared to PM-implants.

A comparative evaluation of the influence of varying gingival biotypes on marginal bone level alterations around dental implants, an in vivo study

A comparative evaluation of the influence of varying gingival biotypes on marginal bone level alterations around dental implants, an in vivo study

Effect of Ratio of Residual Alveolar Bone to Graft Material in Contact With Fixture Surface on Marginal Bone Loss of Implants in Augmented Maxillary Sinuses: A 1-Year Retrospective Study.

The purpose of this retrospective study was to evaluate the influences of height or area ratio of residual alveolar bone to graft material on marginal bone loss around implants in the augmented maxillary sinuses with delayed implant placement. In this study, 42 patients with Astra implants in sinuses that had been augmented with alloplasts and allografts or xenografts (alveolar bone height ≤ 5 mm) were selected. Marginal bone level surrounding 1 implant per sinus was assessed by radiographic imaging at the time of final restoration delivery and 12 months after functional loading. To evaluate the marginal bone level alterations using clinical and radiographic data, Pearson's correlation analysis and Mann-Whitney test were performed. Forty-six implants were included in this study. The residual bone/implant length ratio and the residual bone/implant area ratio were not associated with marginal bone loss at 1 year after functional loading (P > 0.05). And, marginal bone loss did not differ significantly between 2 types of graft materials during the observation period (P > 0.05). The residual bone/implant length ratio and residual bone/implant area ratio were not associated with marginal bone loss around implants placed in augmented sinuses during 1 year of functional loading.

Early loading of splinted implants in the posterior mandible: a prospective multicentre case series.

To evaluate the 12-months clinical and radiological outcomes with the OsseoSpeed(™) TX implant using an early loading protocol in patients with missing teeth in the posterior mandible. Forty-five subjects, with Kennedy class I or II edentulism in the mandible, were enrolled at three centres in China. Two or three implants were placed in one edentulous region using a one-stage procedure. Patients received a screw-retained splinted fixed permanent restoration in one edentulous region 6-8 weeks after surgery. Follow-up took place at 6 and 12 months after loading. Marginal bone level alteration, implant survival and clinical findings were assessed using descriptive statistics. The data were analysed on a patient level, implying that the mean overall implants by patient was used as the statistical unit. The data from the three centres were pooled in the statistical analyses. A total of 107 implants were inserted in 45 patients. Twelve months after loading, the implant survival rate was 100%, with a mean (± std) marginal bone gain of 0.08 ± 0.411 mm and healthy soft tissue status. Early loading of splinted OsseoSpeed(™) TX implants was an effective and safe treatment for partial edentulism of the posterior mandible. CLINICAL TRIAL REGISTRATION NUMBER ON CLINICALTRIALS.GOV: NCT01346683.

Factors affecting peri-implant bone resorption in four Implant supported mandibular full-arch restorations: a 3-year prospective study.

Peri-implant marginal bone-level (MBL) alteration represents one of the parameters included in the criteria for determining implant health. Factors affecting peri-implant MBL alteration for 4-implant-supported fixed mandibular prostheses (4-ISFMP) were assessed. A 3-year prospective, cohort study was conducted on 44 mandibularly edentulous patients treated with 4-ISFMP. Peri-implant MBL alteration was evaluated radiographically at the 12-, 24- and 36-month follow-ups considering to patient-related risk factors [age, gender, diabetes mellitus, smoking, cardiovascular disease (CVD), rheumatic disorders (RD)] and implant/prosthesis-related features (implant location, keratinized gingiva, denture cantilever length, prosthesis supporting zone, opposing dentition) as well as to peri-implant biological parameters (plaque-, bleeding-, calculus index). 148/176 implants (37 patients, drop-out: 15%) were followed for 3 years showing significant (p < 0.001) annual differences of MBL alterations over time. The univariate analysis demonstrated differences of MBL alterations for smokers (p = 0.014), for patients with CVD (p = 0.001) and RD (p = 0.011). In the 3-year multivariate analysis, MBL alteration was influenced by time (p < 0.001) and showed relationship with risk factors as smoking (p < 0.002; OR = 18.965), CVD (p < 0.021; OR = 5.172), RD (p < 0.006; OR = 50.171) and plaque-index (p = 0.034; OR = 3.252). Although peri-implant MBL alteration increased annually, significant odds ratios, were found for patients-related risk factors identifying them potentiating the alterations.

Marginal bone-level alterations of loaded zirconia and titanium dental implants: an experimental study in the dog mandible.

The aim was to test whether or not the marginal bone-level alterations of loaded zirconia implants are similar to the bone-level alterations of a grade 4 titanium one-piece dental implant. In six dogs, all premolars and the first molars were extracted in the mandible. Four months later, three zirconia implants (BPI, VC, ZD) and a control titanium one-piece (STM) implant were randomly placed in each hemimandible and left for transmucosal healing (baseline). Six months later, CAD/CAM crowns were cemented. Sacrifice was scheduled at 6-month postloading. Digital X-rays were taken at implant placement, crowns insertion, and sacrifice. Marginal bone-level alterations were calculated, and intra- and intergroup comparisons performed adjusted by confounding factors. Implants were successfully placed. Until crown insertion, two implants were fractured (one VC, one ZD). At sacrifice, 5 more implants were (partly) fractured (one BPI, four ZD), and one lost osseointegration (VC). No decementation of crowns occurred. All implant systems demonstrated a statistically significant (except VC) loss of marginal bone between baseline and crown insertion ranging from 0.29 mm (VC; P = 0.116) to 0.80 mm (ZD; P = 0.013). The estimated marginal bone loss between baseline and 6 months of loading ranged between 0.19 mm (BPI) and 1.11 mm (VC), being statistically significant for STM and VC only (P < 0.05). The changes in marginal bone levels were statistically significantly different between zirconia implants and control implants (STM vs. BPI P = 0.007; vs. VC P = 0.001; vs. ZD P = 0.011). Zirconia implants were more prone to fracture prior to and after loading with implant-supported crowns compared to titanium implants. Individual differences and variability in the extent of the bone-level changes during the 12-month study period were found between the different implant types and materials.

The Influence of Platform Switching on Clinical, Laboratory, and Image‐Based Measures: A Prospective Clinical Study

This prospective study was conducted to compare the marginal bone level alterations, stability/mobility measurements, and volume of myeloperoxidase (MPO) and nitric oxide (NO) of peri-implant sulcus fluid (PISF) between platform-switched (PS) and standard platform (SP) implants inserted to mandibular premolar/molar regions with a single-stage protocol. Thirty-two (16 PS and 16 SP) implants restorated with fixed prosthesis were included in the study. For both implant systems standard implant dimensions were used. Implant abutment connections and final restorations were made after 3 months of osseointegration. Standard parallel periapical radiographs were used to measure marginal bone loss in over time. Resonance frequency analysis (RFA) and mobility measuring (MM) device were used to determine implant stability/mobility. PISF samples were derived with paper strips and PISF MPO and nitrite level analysis were done spectrophotometrically. Peri-implant parameters were assessed by periodontal indices and all parameters were evaluated at baseline, 1, 3, 6, and 12 months follow-up. No healing problems were recorded for all implants at the end of the study period. At 12 months, mean bone loss measures were 0.84 and 0.76 mm, and mean implant stability quotient (ISQ) values were 74.04 and 76 for PS and SP implants, respectively. Mean MM values were found as -4.82 for PS and -6.26 for SP implants. There were no significant differences between implant types according to PISF volume and laboratory biochemical measures including MPO and NO, and clinical peri- implant indices at any time point. Platform switching seems not to affect the marginal bone level, clinical peri-implant parameters and MPO and NO metabolism around implants inserted to mandibular premolar/molar regions when using a single-stage protocol.

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.

Impact of implant diameter on bone level changes around platform switched implants: preliminary results of 18 months follow‐up a prospective randomized match‐paired controlled trial

This prospective randomized match-paired controlled trial aimed to evaluate the impact of implant platform diameter on marginal bone level around implants restored according to the platform switching (PS) concept. A total of 24 implants were examined in 12 patients. All patients received two adjacent implants inserted at the crestal level: 4.3mm (control group) and 4.8mm (test group) in diameter. Mesio-distal implant position was randomly performed. According to the PS concept, for restoration, a 3.8 and 4.3mm diameter abutment was used, respectively in the control and test groups, resulting, in both groups, with 0.25mm of implant/abutment mismatching. Implant restorations were splinted. Eighteen months after final restoration, periapical standardized digital radiographs were taken to evaluate marginal bone level alterations after loading. The Wilcoxon Signed-Rank Test was selected to identify differences between groups. At the last follow-up, control implants exhibited a mean bone loss value of 1.10mm (SD: 0.47mm); the test group showed a mean value of 1.09mm (SD: 0.08mm). No statistically significant differences were found between test and control groups. Within the limits of this study, the present results suggest that bone resorption is mostly related to biologic (biologic width re-establishment) rather than to biomechanical factors (implant platform diameter). Furthermore long-term studies with a wider sample size are needed to confirm the platform diameter influence on hard tissue response around implants restored according to the PS concept.