Peri-implant Marginal Bone Resorption Research Articles

Clinical efficacy of simple taper retentive implants in immediate posterior dental implantation for 5-7 years.

This study aimed to evaluate the long-term clinical efficacy of simple taper retentive implants in the posterior dental area after immediate implantation for 5-7 years. Selected from January 2015 to December 2017 in the Fourth Affiliated Hospital of Nanchang University dental clinic line tooth area immediately after the implant prosthesis, a total of 38 patients, 53 implants, were deep into (bone under 2 mm or higher) and the upper structure was repaired. In addition, after the completion of tracking observation of 60-90 months, the implant surrounding bone health was recorded and analyzed. After 5-7 years of follow-up, 1 of the 53 implants failed to fall out, and the implant retention rate was 98.1%. The amount of bone resorption in the proximal and distal margins 5-7 years after implant restoration was (0.16±0.94) mm and (-0.01±1.29) mm, respectively, and the difference in bone height between the proximal and distal margins of the implant and the immediate post-restoration period was not statistically significant (P>0.05). No statistically significant differences were found in the effects of periodontitis, implant site inflammation, and smoking on peri-implant marginal bone resorption (P>0.05). The single taper-retained implant broadens the indications for immediate implant placement in the posterior region, and its deep sub-osseous placement (≥2 mm below the bone) avoids to a certain extent the disturbance of the implant by external stimuli and the exposure of the cervical abutment of the implant, with the good long-term stability of the marginal bone around the implant.

A prospective, blinded, randomized-controlled study on regressive bone modeling around dental implants with different machined coronal portion

Scientific evidence showed variable degree of marginal bone loss around dental implants both during integration process and during function. Among the different factors that seem to influence this process, a crucial role is up to the crestal module of dental implant. In order to reduce marginal bone loss, different configurations of crestal module have been proposed. The aim of this study was to evaluate the efficacy of half treatment dental implants with a coronal smooth portion of 3.5 mm compared to rough surfaced implants with a smooth coronal portion of 0.5mm, to reduce peri-implant marginal bone resorption. The degree of marginal bone loss was assessed through radiological measures. In addition, soft tissues healing was evaluated through plaque index and gingival index. The results demonstrated a significantly (p= 0.03) lower value of MBL (mean 0.7mm), than HT implants (mean 1.03mm) after 1year functional loading. In conclusion, use of FT implants could be determine better results in order to reduce MBL.

Influence of apico-coronal positioning of tissue-level implants on marginal bone stability during supracrestal tissue height establishment: A multi-center prospective study.

Supracrestal tissue height establishment is a crucial factor influencing peri-implant marginal bone modifications prior to prosthesis delivery. If mucosal thickness is insufficient, peri-implant marginal bone resorption occurs to allow appropriate supracrestal tissue height formation. This study evaluates if marginal bone resorption occurring around tissue-level implants before prosthetic loading could be compensated by adapting apico-coronal positioning to mucosal thickness. Patients requiring placement of one single implant in the posterior mandible were treated with tissue-level implants with a 3-mm high transmucosal machined component and moderately rough implant body. Based upon vertical mucosal thickness measured after buccal flap reflection, implants were placed with the treated part: (group 1) 2 mm below crestal level in presence of thin mucosa (<2.5 mm); (group 2) 1 mm below the crestal level in presence of medium mucosa (2.5-3.5 mm); (group 3) at equicrestal level in presence of thick mucosa (>3.5 mm). Forty-nine implants, placed in 49 patients were included in final analysis (group 1: 18 implants; group 2: 16 implants; group 3: 15 implants). Mean marginal bone resorption after 5months of healing was 0.66 ± 0.49 mm, 0.32 ± 0.41 mm, and 0.22 ± 0.52 mm in groups 1, 2, and 3, respectively. Inter-group analysis highlighted significant differences between the three groups after ANOVA test (p=0.025). However, adaptation of apico-coronal implant positioning in relation to mucosal thickness, allowed to avoid early exposure of the treated surface in 100%, 93.7%, and 53.3% of the implants in groups 1, 2, and 3, respectively. During supracrestal tissue height formation, tissue-level implants inserted adapting apico-coronal positioning in relation to mucosal thickness exhibited greater marginal bone resorption at sites with thin mucosa than at sites with medium or thick mucosa. However, anticipating supracrestal tissue height establishment by adapting apico-coronal implant positioning in relation to mucosal thickness may effectively prevent unwanted exposure of treated implant surface.

Effect of restoration material on marginal bone resorption around modified anatomic zirconia dental implants: A randomised controlled trial

ObjectiveThe primary aim of this study was to determine the effect of implant-supported porcelain-fused-to-metal (PFM) and indirect-composite-resin (ICR) fixed dental prostheses on peri-implant marginal bone resorption (MBR) in custom-made anatomic modified zirconia dental implants. MethodsA prospective randomized controlled clinical trial was conducted. Participants with premolars indicated for dental extractions were recruited into this study to receive a single-unit implant-supported fixed dental prosthesis. Modified anatomic zirconia implants with thorny-retentive surfaces were placed and loaded randomly after 3 months with either PFM or ICR crowns. Participants were recalled after 12 and 18 months for radiographic evaluation of peri-implant MBR. Implants survival was also reported. Results18 out of 20 zirconia implants were included in all study phases. 18-month survival rate was 90%. After 12 months of implant placement, the mean MBR values were 0.53 (±0.21) mm and 0.60 (±0.14) mm in the ICR group compared to 0.67 (±0.16) mm and 0.61 (±0.27) mm in the PFM group. In the 18-month follow-up, the mean MBR values were 0.61 (±0.27) and 0.67 (±0.16) mm in the ICR group compared to 0.77 (±0.29) and 0.77 (±0.27) mm in the PFM group. No significant differences were found in MBR mean values between study groups at 12- and 18-month follow-up points. ConclusionThis study showed that PFM and ICR crowns were viable zirconia-implant-supported restorations with no preference regarding MBR after 18 months. Nevertheless, long-term evaluations are warranted.

Marginal Bone Resorption Around Dental Implants Placed in Alveolar Socket Preserved Sites: A 5 Years Follow-up Study

The present study evaluated the clinical and radiological stability of hard and soft tissues following alveolar socket preservation (ASP) procedure with a follow-up of 5 year from implant insertion. The initial sample consisted of seven patients who underwent single tooth extraction and ASP procedure by means of demineralized bovine bone mineral particles covered with a porcine-derived non-cross-linked collagen matrix (CM). Each patient received a submerged single implant in the healed site. Mesial and distal peri-implant marginal bone resorption (MBR) rates were assessed radiographically at 1 year (T1) and 5 years (T2) after implant placement (baseline value). No dropouts occurred up to 5 years. At T1, the MBR was 0.08 ± 0.16 mm at the mesial aspect and 0.1 ± 0.12 mm at the distal aspect. This difference was not statistically significant (P = 0.867). At T2, the mesial MBR was 0.15 ± 0.17 mm and the distal MBR was 0.11 ± 0.14 mm, with a non-statistically significant difference (P = 0.532). Therefore, no statistically significant differences were detected comparing mesial and distal MBR at any time point. With respect to the intra-group comparisons, no differences were observed comparing the different study periods within each variable. Indeed, the comparison between T0, T1 and T2 was non-statistically significant at both mesial (P = 0.06) and distal (P = 0.06) aspects. After 5 years, the volume of the soft tissues appeared clinically well maintained with a natural aspect around dental implants and adjacent teeth. ASP using demineralized bovine bone mineral in combination with CM proved to be an effective technique to maintain stable dimensional volumes of both hard and soft tissues.

Splinting of Mini Implants Used to Assist Complete Mandibular Overdentures with Two Different Bar Designs: A 3-Year Clinical and Radiographic Study

Purpose : Clinical and radiographic evaluation of early loaded four splinted mini dental implants (MDIs) with two different bar designs for assisting mandibular complete overdenture. Materials and Methods: Twenty completely edentulous patients (10 males and 10 females) with mean age of 52.5 years old were selected for this study.All patients received four mini implants in the mandibular interforaminal area. Patients were assigned into two equal groups according to splinting bar design, where it was milled bar for Group I and round bar joint for Group II. Maxillary complete denture was constructed for each patient against implant assisted mandibular overdenture. Periimplant soft tissue health parameters were monitored and cervical bone height changes were evaluated through standardized periapical radiographs just after loading of mini implants and 6, 12, 24 and 36 months later as represented by (T 0), (T6), (T12), (T24), and (T 36) respectively. Results: Insignificant difference of all peri-implant soft tissue health arameters was observed over time within each group and between the two groups at all observational times. Peri-implant marginal bone resorption was significantly higher in group I in comparison to group II at T 6, T12 and T36. Significant difference was found between T0 and T6 in both groups and also between T24 and T36 in group I. Conclusions: Both milled and round bar splints can provide a satisfactory clinical outcome for early loaded mini implants assisting mandibular complete overdenture. However, splinting with milled bars seems to be associated with a higher rate of peri-implant marginal bone loss.

Prosthetic Complications Affecting Single-Tooth Morse-Taper Connection Implants.

To evaluate the long-term cumulative implant survival rate (CISR%) and cumulative implant-crown success rate (CICSR%) of single-tooth Morse-taper connection implants, with particular attention to documenting the incidence of prosthetic complications. The customized records of all patients who had been treated with single-tooth Morse-taper connection implants in 2 dental centers during the period between January 2002 and December 2012 were revisited. These records included patient-related (gender, age at surgery, smoking, bruxism), implant-related (date of insertion, site/location, and length/diameter of the implant, previous/concomitant bone regeneration), and restoration-related (date of delivery of the provisional and final crown) information. In addition, these records contained information about any implant failure and biologic and/or prosthetic complication that occurred during the follow-up period as well as the radiographic documentation. The follow-up period comprised between 5 and 15 years. The main outcomes were CISR% and CICSR%, with the latter being defined as the condition in which no complication had affected the surviving implant-supported crown during the entire follow-up. Life-table analysis was used for the analysis of CISR% and CICSR%. Peri-implant marginal bone resorption (PIMBR) at 5, 10, and 15 years was a secondary outcome of this study. In total, 578 patients who had received 612 implants were included in this study. The overall CISR% at 15 years was 94.8% (94.2% maxilla, 95.3% mandible). Among the surviving crowns, the overall CICSR% at 15 years was 94.5% (93.1% and 94.9% for anterior and posterior crowns, respectively), and the incidence of prosthetic complications was low (1.5%). The PIMBL amounted to 0.38 ± 0.29 mm, 0.49 ± 0.35 mm, and 0.94 ± 0.58 mm at the 5-, 10-, and 15-year follow-ups, respectively. Morse-taper connection implants represent a reliable treatment procedure for the restoration of single-tooth gaps in the long term, with high CISR% (94.8%) at 15 years, a very low incidence of complications, and a high CICSR% (94.5%).

Evaluation of peri-implant marginal tissues around tissue-level and bone-level implants in patients with a history of chronic periodontitis.

To evaluate clinical and radiographic characteristics in peri-implant marginal tissues in patients with a history of chronic periodontitis, rehabilitated using tissue-level or bone-level implants. Using a split-mouth design, 20 patients with a history of chronic periodontitis were selected and received two different implants, tissue-level group (n=20) and the bone-level group (n=20). Peri-implant probing depth, relative peri-implant mucosal margin position, relative peri-implant clinical attachment level, peri-implant plaque index and peri-implant bleeding on probing were evaluated at prosthesis installation, 1, 3, 6, 12 and 24months after implant loading. Radiographic marginal bone level was evaluated at implant insertion, prosthesis installation, 6 and 24months after implant loading. The mean difference of peri-implant marginal bone resorption from implant installation to 24months in function was 0.75±1.12mm for the tissue-level group and 0.70±0.72mm for the bone-level group. No statistically significant difference was found between groups at all assessment periods for clinical and radiographic peri-implant evaluation. Under a rigid supportive therapy, both approaches performed likewise regarding clinical and radiographic parameters for rehabilitation of patients with a history of chronic periodontitis.

Mandibular Full‐Arch Fixed Prostheses Supported on 4 Implants with Either Axial Or Tilted Distal Implants: A 3‐Year Prospective Study

This prospective study evaluated the clinical and radiographic outcome of distally cantilevered 4-implant-supported fixed mandibular prostheses (4-ISFMP) with distal implants either in axial or distally tilted direction. Forty-one mandibulary edentulous patients received acrylic veneered 4-ISFMP with casted framework. Based on distal implant placement direction patients were assigned to 2 groups: 21 patients with four (2 anterior/2 posterior) axial implants (axial-group I) and 20 patients with 2 anterior axial/2 distal tilted implants (tilted-group II). Patients were prospectively followed for 3 years by annual examinations of implants and prosthetic survival rates including assessment for biological and mechanical complications. Additionally, peri-implant marginal bone resorption [MBR], pocket depth [PD], plaque index [PI], bleeding index [BI] and gingival index [GI], and calculus index [CI] were evaluated at each annual follow-up. 37/41 patients (19 axial-group I, 18 tilted-group II) and 148/164 implants were followed at the 1-, 2-, and 3-year evaluation (dropout rate: 11.8%) presenting no implant and denture loss (100% survival). The overall, MBR at year 1, 2, and 3 was 1.11 ± 0.4 mm, 1.26 ± 0.42 mm, and 1.40 ± 0.41 mm, respectively, representing a significant (p < .001) continuing time depending annual reduction. MBR and PD did not differ between anterior and posterior regions in both groups or for anterior and posterior regions between the groups. PI and CI were significantly (p < .001) higher for implants in anterior regions than for posterior regions in both groups. Moreover, posterior implant regions showed significantly (p < .001) higher PI and CI for axial-group I than for tilted-group II over time. Biological and mechanical complications as well as GI and BI did not differ between the groups over a 3-year follow-up period. For clinical implant and prosthesis outcome no statistical significant mean differences were noted for distally cantilevered 4-ISFMP supported by distal implants placed in tilted or axial direction.

Implant angulation: 2-year retrospective analysis on the influence of dental implant angle insertion on marginal bone resorption in maxillary and mandibular osseous onlay grafts.

The purpose of this study was to determine the existence of correlations between marginal peri-implant linear bone loss and the angulation of implants in maxillary and mandibular augmented areas over the course of a 2-year survey. Dependent variables described the sample of the present retrospective chart review. By using three-dimensional radiographs, input variables, describing the implant angulation (buccal-lingual angle [φ] and mesial-distal angle [θ]) were measured; outcome variables described survival rate and marginal bone resorption (MBR) around dental implants in autogenous grafts (10 maxillae and 14 mandibles). Pairwise comparisons and linear correlation coefficient were computed. The peri-implant MBR in maxillary buccal and palatal areas appeared less intensive in the presence of an increased angulation of an implant towards the palatal side. Minor MBR was recorded around mandibular dental implants positioned at a right angle and slightly angulated towards the mesial. Resorption in buccal areas may be less intensive as the angulation of placed implants increases towards the palatal area in the maxilla, whereas for the mandible, a greater inclination towards the lingual area could be negative. In the mandibular group, when the implant was slightly angulated in the direction of the distal area, bone resorption seemed to be more marked in the buccal area. In the planning of dental implant placement in reconstructed alveolar bone with autograft, the extremely unfavourable resorption at the buccal aspect should be considered; this marginal bone loss seemed to be very sensitive to the angulation of the dental implant.

A 3-Year Prospective Clinical Study of Telescopic Crown, Bar, and Locator Attachments for Removable Four Implant–Supported Maxillary Overdentures

To evaluate telescopic crown (TC), bar, and locator attachments used in removable four implant-supported overdentures for patients with edentulous maxillae. A total of 30 maxillary edentulous patients were enrolled in a 3-year prospective study. Ten patients (group A) were treated with overdentures supported by TCs, 10 patients (group B) with overdentures supported by bar attachments, and 10 patients (group C) with overdentures supported by locator attachments. A total of 120 implants were used to restore oral function. During the 3-year follow-up period, implant survival and success rates, biologic and mechanical complications, prosthodontic maintenance efforts, and patient satisfaction were evaluated. All 30 patients were available for the 3-year follow-up and exhibited 100% implant survival and success rates. Peri-implant marginal bone resorption was not statistically significant for the three groups. There were lower plaque, bleeding, gingiva, and calculus indices in group C compared with groups A and B. The number of prosthodontic maintenance visits revealed eight complications in the TC group, seven complications in the bar group, and four complications in the locator group. However, there were no differences in the clinical effects of the overdentures in the three groups. Within the limits of this prospective study, it was concluded that the locator system produced superior clinical results compared with the TC and bar attachments in terms of peri-implant hygiene parameters, the frequency of prosthodontic maintenance measures, cost, and ease of denture preparation. However, longer-term prospective studies are required to confirm these results.

Dimensional changes in soft tissues around dental implants following free gingival grafting: an experimental study in dogs

To study the buccal dimensional tissue changes at oral implants following free gingival grafting, with or without including the keratin layer, performed at the time of implant installation into alveolar mucosa. The mandibular premolars and first molars were extracted bilaterally in six Beagle dogs. In the right side of the mandible (Test), flaps were first elevated, and the buccal as well as part of the lingual masticatory mucosa was removed. An incision of the periosteum at the buccal aspect was performed to allow the flap to be coronally repositioned. Primary wound closure was obtained. In the left side, the masticatory (keratinized) mucosa was left in situ, and no sutures were applied (Control). After 3 months of healing, absence of keratinized mucosa was confirmed at the test sites. Two recipient sites were prepared at each side of the mandible in the region of the third and fourth premolars. All implants were installed with the shoulder placed flush with the buccal alveolar bony crest, and abutments were connected to allow a non-submerged healing. Two free gingival mucosal grafts were harvested from the buccal region of the maxillary canines. One graft was left intact (gingival mucosal graft), while for the second, the epithelial layer was removed (gingival connective tissue graft). Subsequently, the grafts were fixed around the test implants in position of the third and fourth premolars, respectively. After 3 months, the animals were euthanized and ground sections obtained. Similar bony crest resorption and coronal extension of osseointegration were found at test and control sites. Moreover, similar dimensions of the peri-implant soft tissues were obtained at test and control sites. The increase in the alveolar mucosal thickness by means of a gingival graft affected the peri-implant marginal bone resorption and soft tissue recession around implants. This resulted in outcomes that were similar to those at implants surrounded by masticatory mucosa, indicating that gingival grafting in the absence of keratinized mucosa around implants may reduce the resorption of the marginal crest and soft tissue recession.

Clinical Outcome and Peri-implant Findings of Four-Implant–Supported Distal Cantilevered Fixed Mandibular Prostheses: Five-Year Results

This retrospective study evaluated implant and prosthodontic survival/success rates of four-implant-supported distal cantilevered mandibular fixed prostheses over more than 5 years of clinical use. Patients with mandibular edentulism treated with four-implant mandibular prostheses with distal extensions were evaluated. Cumulative implant survival/success rates, peri-implant conditions, and prosthodontic maintenance efforts were assessed. Relationships between the degree of distal implant tilting, length of cantilevers, and implant-generated supporting zone were evaluated. Thirty-eight patients with 152 implants (90.5% of the original sample) were available for follow-up after 5 to 7 years (mean follow-up, 66.5 ± 3.1 months). The cumulative survival and success rates for included implants were 100% and 98.6%, respectively. Denture cantilever length (mean, 14.7 ± 2.3 mm; range, 9 to 20 mm) and implant-generated supporting zone (mean, 318.9 ± 48.1 mm(2); range, 225 to 410 mm(2)) showed significant positive and negative correlations, respectively, with the inclination of tilted distal implants toward the occlusal plane (76 ± 7.2 degrees; range, 65 to 90 degrees). Peri-implant marginal bone resorption (1.5 ± 0.4 mm) and pocket depths (1.8 ± 0.8 mm) were similar for anterior and posterior implants and were not influenced by degree of tilting or cantilever length. Plaque and calculus conditions were poorer for anterior implants than for posterior implants. No dentures fractured; however, fractures of resin tooth veneer material, denture rebasing, and a strong need for cleaning as a result of resin discoloration were seen. Fixed four-implant rehabilitations with distal cantilevers of a defined length with or without distally tilted implants showed high success rates. Inferior hygiene in the anterior mandible regions may be a result of reduced cleansability and variations in anatomical landmarks. Resin veneering proved advantageous for repair or modification but disadvantageous for discoloration.

Removable four implant‐supported mandibular overdentures rigidly retained with telescopic crowns or milled bars: a 3‐year prospective study

The present study evaluated implant survival/success rate, peri-implant parameters and prosthodontic maintenance efforts for four implant-supported mandibular overdentures (IOD) rigidly retained on either milled bar or double crowns (telescopic) attachments. In a randomized prospective trial, 51 patients with edentulism received four mandibular interforaminal implants and complete maxillary dentures. For IOD, rigid denture stabilization was chosen randomly selecting 26 patients for milled bars (group I) and 25 patients for double (telescopic) crowns (group II). During a 3-year follow-up period, implant survival/success, peri-implant parameters (marginal bone resorption, pocket depth, plaque-, bleeding-, gingival index [BI and GI], calculus) and prosthodontic maintenance efforts were evaluated and compared between both retention modalities used. Forty-five patients (23 group I, 22 group II) were available for a 3-year follow-up (dropout rate: 11.8%) presenting a high implant survival/success rate (100%). Peri-implant marginal bone resorption, pocket depth as well as BI and GI did not differ for both rigid retention modalities. However, annually higher values for plaque- (NS) and calculus index (P<0.035) were noticed for the bar (group I) than for the telescopic crown (group II) attachments. Prevalence of prosthodontic maintenance did not differ between both retention modalities (group I: 0.41/maintenance efforts/year/patients vs. group II; 0.45 maintenance/efforts/year/patients). However, prosthodontic adaption for handling mechanism showed benefits for the bar retention. Rigid anchoring of IOD retained either by bar or telescopic attachments showed high implant success rates and minor prosthodontic maintenance efforts regardless of retention modalities used. Stable denture retention presented healthy peri-implant structure for implants in bar and telescopic anchoring systems. Drawbacks such as higher plaque/calculus for bar retention and less favorable handling properties (output) for telescopic crown attachment leave the decision on the selection at the discretion of the clinician.

Porcine Bone Used in Sinus Augmentation Procedures: A 5-Year Retrospective Clinical Evaluation

Rehabilitation of the edentulous posterior maxilla with dental implants often represents a clinical challenge because of the insufficient bone volume resulting from pneumatization of the maxillary sinus and crestal bone resorption. The aim of this study was a retrospective clinical evaluation of maxillary sinus augmentation using porcine bone. One hundred twenty-one healthy patients with a noncontributory medical history were included in this study. All patients underwent sinus augmentation procedures with porcine bone. After a 4- to 6-month healing period, sandblasted and acid-etched implants were inserted. All grafted sinuses healed without major complications, except for 2 that showed no regeneration at the time of implant placement. A total of 21 implants were lost, 8 after the second-stage surgery and 13 in the 5 years' follow-up after loading. The cumulative survival rate was 92% after a mean loading time of 5 years. Only minor peri-implant marginal bone resorption was found. Within the limitations of this study, porcine bone can be used with success in sinus augmentation procedures, and rougher-surfaced implants are probably preferable.