Marginal bone loss one year after implantation: a systematic review of different loading protocols

Influence on marginal bone levels at implants equipped with blades aiming to control the lateral pressure on the cortical bone. An experimental study in dogs

BACKGROUND

To avoid cortical compression, several implant systems have included in the protocol dedicated drills aimed at widening the cortical region of osteotomy. However, the manual execution of this operation does not guarantee the necessary precision. Hence, the present study aimed to determine the optimal size of the recipient site at the level of the alveolar crest in relation to the size of the coronal region of the implant to achieve the best healing result.

MATERIALS AND METHODS

Blades of different diameters were incorporated into the coronal part of the implant to prepare the cortical region of the mandibular alveolar bone crest in different dimensions in relation to the collar of the implant. The differences in diameter of the blades in relation to the collar of the implant were as follows: one control group, -175 μm, and three test groups, 0 μm, + 50 μm, or + 200 μm.

RESULTS

The marginal bone loss (MBL) at the buccal aspect was 0.7 mm, 0.5 mm, 0.2 mm, and 0.7 mm in the - 175 μm, 0.0 μm, + 50 μm, + 200 μm groups, respectively. The differences were statistically significant between group + 50 μm and control group - 175 μm (p = 0.019), and between + 50 μm and + 200 μm (p < 0.01) groups. The level of osseointegration at the buccal aspect was more coronally located in the test groups than in the control group, whereas the bone-to-implant contact percentage was higher in the + 50 μm and + 200 μm groups. However, these differences were not statistically significant.

CONCLUSIONS

The lowest bone crest resorption and highest levels of osseointegration were observed in the 0.0 μm and + 50 μm groups. The cortical region where the blades had performed their cutting action showed regular healing with perfect hard and soft tissues sealing in all the groups. Cortical blades gathered bone particles, particularly in the + 200 μm group, which were incorporated into the newly formed bone. The results from the present experiment provide support to the use of blades that produce a marginal gap of 50 μm after implant insertion.

The influence of immediate intraoperative loading with a splinting component on supporting tissues during a one-stage implant

OBJECTIVE

Aim: To study the specifics of the impact of immediate intraoperative loading with a splinting component on supporting tissues during a one-stage implantation protocol.

PATIENTS AND METHODS

Materials and Methods: In the course of the study, orthopedic treatment was carried out for 55 patients aged 29 to 60 years. The following were performed: cone-beam computed tomography, software planning and intraoral scanning with an optical scanner, one-stage implantation protocol, assessment of implant stability with the Osstell ISQ device, microcirculation study in the peri-implant area using laser Doppler flowmetry (LDF).

RESULTS

Results: It was established that around loaded implants there is an increase in blood flow and vasomotor activity of the microcirculatory channel of the supporting tissues, an increase in the volume of bone tissue and an increase in torque, which is the optimal forecast for the acceleration of the pace of osseointegration.

CONCLUSION

Conclusions: The use of a splinting component during immediate intraoperative functional masticatory load accelerates the dynamics of bone tissue remodeling processes around the implant, which is an optimal prediction of osseointegration rates in various dental implantation protocols and is consistent with high values of the implant stability coefficient.

Cumulative success rate and marginal bone loss for immediate and early loading protocols in a single implant-supported crown: A randomized controlled split-mouth clinical trial

STATEMENT OF PROBLEM

New loading protocols with reduced treatment time have gained popularity because of their advantages. However, whether the success rate with immediate loading (IL) is worse than with early loading (EL) is still unclear.

PURPOSE

The purpose of this randomized controlled trial with a split-mouth design was to evaluate the marginal bone loss and the cumulative success rate (CSR) 1 year after an IL protocol in single implant-supported crowns. The test groups were loaded after less than 24 hours (test group) and EL at 60 days (control group).

MATERIAL AND METHODS

Seventeen participants received 34 implants. The recall appointments were at baseline, 30 days, 60 days, and 1 year. The outcome measures evaluated were pain, implant clinical mobility, probing depth measurements, peri-implant disease, marginal bone loss, implant insertion torque, implant stability quotient (ISQ) value, and the CSR. A 2-way repeated measures ANOVA identified the significant differences for probing depth and ISQ. A 3-way repeated measures ANOVA followed by a pairwise t test analyzed marginal bone loss, and a nonparametric Wilcoxon test analyzed insertion torque (α=.05).

RESULTS

No differences were found between the insertion torque, ISQ, and marginal bone loss values (P>.05). When analyzing probing depth, no differences were found when comparing IL versus EL at baseline, 30 days, and 1 year (P>.05). The global CSR was 91.17%, 88.23% for the IL group and 94.11% for the EL group.

CONCLUSIONS

When analyzing marginal bone loss, the groups were similar. The global CSR was 91.17%, 88.23% for the IL group, and 94.11% for the EL group.

Full arch immediate occlusal loading using site specific implants: A clinical series of 10 patients (13 arches)

PURPOSE

Osseointegration of dental endosseous implants has proven to be effective, predictable, and clinically successful. Unloaded healing protocols were originally used in treating edentulous patients. Full arch immediate occlusal loading protocols have been shown to be as effective as unloaded healing protocols. This paper reports on the results, benefits, and limitations of one specific immediate loading protocol using site specific implants for fresh extraction and healed extraction sites.

MATERIALS AND METHODS

Ten consecutive patients [{13 arches} (age range: 64-81 years; average: 70.1) (4 males/6 females) were treated by the first 2 authors in private practice settings. Hopeless teeth were scheduled for extraction with immediate implant placement and immediate loading with insertion of full arch, screw-retained, acrylic resin interim prostheses within 24 hours. Implants were also placed into healed edentulous ridges. Insertion torque values for each implant were recorded. Interim prostheses were removed after at least 3 months of healing. Implants were reverse torque tested (35 Ncm) and evaluated for macroscopic mobility. Definitive full arch prostheses were made. Patients were followed for 21 to 48 months postimplant surgery. Panoramic radiographs were taken immediately postimplant placement and 1 year postoperative.

RESULTS

Thirteen arches were treated; 11 ultrawide diameter implants were placed into molar sockets, 26 inverted body-shift implants were placed into anterior sockets; 25 standard diameter, tapered implants were placed into edentulous sites; 2 zygomatic implants were placed in one patient. The total number of implants placed was 64 (4 preexisting implants were also used and not included in this study). The minimum implant insertion torque value was 20 Ncm. After 12 to 18 months of function (average 14 months), the implant and prosthetic survival rates were 100%. Eight patients were restored with definitive zirconia or acrylic resin hybrid fixed prostheses. Two patients were restored with bar titanium frameworks and removable overdenture prostheses. No prosthetic complications were reported for the definitive prostheses.

CONCLUSIONS

The results of this clinical series with site specific implants and immediate full arch occlusal loading in treating edentulous patients resulted in 100% clinical implant and prosthetic survival rates. According to this study, this protocol can be used with high levels of anticipated success.

EVALUATION OF DYNAMIC CHANGES IN THE MICROCIRCULATION OF THE MUCOSA IN THE ZONE OF DENTAL IMPLANTATION WITH IMMEDIATE INTRAOPERATIVE LOAD

OBJECTIVE

The aim: Study of the dynamics of changes in the average values of the index of mucosal microcirculation after dental implantation with immediate intraoperative prosthetics.

PATIENTS AND METHODS

Materials and methods: In clinical conditions, 55 patients aged from 29 to 60 years with a diagnosis of partial absence of teeth requiring orthopedic treatment using implants on the lower jaw were treated and examined. In the course of the latest achievements, the following methods were used: clinical protocol of immediate implantation with Solidum and Simplex implants of the «ART IMPLANT» system on the lower jaw by the one-stage implantation method, with immediate intraoperative loading and the manufacture of a temporary non-removable dental prosthesis, determination of the microcirculation index in dynamics using the laser Doppler method flowmetry, statistical analysis.

RESULTS

Results: The obtained results indicate a pronounced reaction of microcirculation up to the 3rd day after surgery, an increase in blood perfusion of the mucous membrane by 2.7 times while maintaining vasomotor activity, which indicates adaptation to the injury and immediate loading of the denture in the postoperative period. 3 months after dental surgery and immediate intraoperative prosthetics, all indicators of microcirculation approach the initial values before surgery.

CONCLUSION

Conclusions: With the help of laser Doppler flowmetry, the fact of a sharp restoration of microcirculation after dental implantation surgery with immediate intraoperative prosthetics is confirmed.

A Comparative Clinical Evaluation of Effectiveness of Platelet-Rich Plasma, Synthetic Allograft, and Bioresorbable Xenograft During Immediate Implant Placement

BACKGROUND

The use of an appropriate graft material helps in an adequate amount of osseointegration. The objective of this study was to compare the efficacy of platelet-rich plasma (PRP), a synthetic allograft (PerioGlas), and Bio-Oss, a bioresorbable xenograft in immediate implant procedures.

METHODS

In this randomized, prospective study, 90 patients were categorized into three groups with 30 samples in each as Group A: patients who received PRP with an immediate implant; Group B: immediate implants with synthetic allograft (PerioGlas); and Group C: patients with immediate implants placed using bioresorbable xenograft (Bio-Oss). Postoperative follow-up was done based on plaque and gingival index, measurement of probing depths, and resorption of bone. Obtained data were statistically analyzed using the "one-way analysis of variance (ANOVA)" test.

RESULTS

Inter-group statistical comparisons between gingival and plaque indices at three, six, and 12 months of follow-up in the study groups demonstrated no statistical significance (p > 0.05). The mean probing depths and resorption of bone at three, six, and 12 months of follow-up were statistically nonsignificant (p > 0.05) on the inter-group comparison.

CONCLUSION

It could be concluded from the present study that there is no statistical superiority observed among PRP, PerioGlas, or Bio-Oss in terms of their usage as a graft material along with immediate implant placement procedure.

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

INTRODUCTION

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.

METHODS

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).

RESULTS

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 5 months 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.

CONCLUSION

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.

Hybrid Funnel Technique: A Novel Approach for Implant Site Preparation: A Pilot Study

(1) Background: Different techniques and tools have been developed for implant site preparation. In this clinical scenario, Hybrid Funnel Technique (HFT), a novel osteotomy procedure, has been proposed. (2) Aim: The aim of this retrospective observational study was to consider the different responses to compression of the histological bony compartments (cancellus and cortical). HFT involves the use of multiple drills for the cortical layer preparation and of an osteotome for the osteocompaction of the cancellous bone. (3) Materials and Methods: Following computer-supported implant planning and guided surgery, 10 osteotomies with HFT were performed and 10 implants with the same length and diameter were placed in seven healthy and no daily smoking patients. Periapical X-ray and intraoral photographs were performed at baseline and after 12 months of follow-up to evaluate marginal bone level (MBL) changes and aesthetic results obtained from implant prosthetic rehabilitation. (4) Results: At 1 year of follow-up, 100% of the implants were successfully integrated, MBL change mean value was 0.17 mm ± 0.21. No differences in terms of MBL were noted between thin and thick biotypes. Pink esthetic score (PES) and white esthetic score (WES), assessed one year after definitive restoration placement, were 7.5 ± 2.3 and 8.5 ± 1.1, respectively. (5) Conclusions: Based on the findings of this preliminary clinical study, HFT has led to stability of peri-implant tissues and could represent a reliable technique for surgical preparation of the implant site.

Biomechanical variables affect peri-implant bone loss in implant-supported fixed complete dentures: a methodological and prospective study

PURPOSE

Implant-supported fixed complete dentures (IFCD) experience failures and complications related to biological and technical risk factors. This study investigated the effect of biomechanical variables of IFCD on 1-year peri-implant bone loss at the buccal, palatal/lingual, mesial, and distal implant sides. A new method was used to measure the geometric biomechanical variables of IFCD using cone beam computed tomography (CBCT).

METHODS

The study sample consisted of 246 external hexagon implants supporting 48 hybrid IFCD in 44 patients. CBCT images obtained immediately (T0) and 1 year (T1) after prosthesis installation were used to measure the support polygon area, clinical crown/implant (C/I) ratio (vertical lever), anteroposterior power and resistance arms, anterior and posterior cantilevers (horizontal levers), and peri-implant bone remodeling (T1-T0). Data were analyzed using multilevel multivariable models.

RESULTS

The average total bone loss in the mandible and maxilla were 0.88 mm, with a loss of 0.62 mm in the mandible and 1.08 mm in the maxilla. The C/I ratio had a significant effect on bone loss on the mesial, distal, and palatal/lingual sides (P <.05). The anterior cantilever had a protective effect on the lingual side of the anterior implant. No effect on bone loss was found for the support polygon area, posterior cantilever, resistance arm, or power arm (P >.05).

CONCLUSIONS

The results suggest that the C/I ratio and anterior cantilever in IFCD affect peri-implant bone loss according to the implant side and position in the arch.

Comparison of sandblasted and acid-etched surface implants and new hydrophilic surface implants in the posterior maxilla using a 3-month early-loading protocol: a randomized controlled trial

Objectives

In this prospective randomized controlled trial, we measured the primary and secondary stability of two surface-treated implants placed in the posterior maxilla, applied 3-month loading protocols, and compared and analyzed the short-term outcomes of the implants.

Patients and Methods From June 2018 to June 2019, patients with a residual bone height of 4 mm in the posterior maxilla were enrolled and randomly divided into two groups to place SA implants (Osstem Implants, Korea) in Group A and NH implants (Hiossen, USA) in Group B. Finally, 14 implants placed in 13 patients in Group A and 17 implants placed in 14 patients in Group B were analyzed. The measured primary and secondary stability of each implant was represented by implant stability quotient (ISQ), and treatment outcomes were evaluated.

Results

Group A consisted of patients with an average age of 62.2 years (range, 48-80 years), and Group B consisted of patients with an average age of 58.1 years (range, 35-82 years). Primary stability was 73.86±6.40 and 71.24±5.32 in Groups A and B, respectively (P=0.222). Secondary stability was 79.07±5.21 in Group A and 78.29±4.74 in Group B (P=0.667). A steep increase in ISQ during the healing period was observed in Group B, though it was not significant (P=0.265). The mean follow-up period was 378.5±164.6 days in Group A and 385.3±167.9 days in Group B. All implants in each group met the success criteria, and the success rate was 100%.

Conclusion

Two surface-treated implants placed in the posterior maxilla with greater than 4 mm alveolar bone height exhibited successful one-year treatment outcomes if a primary stability of 65 or higher ISQ was obtained and a 3-month early loading protocol was applied.

Socket shield technique: A systematic review of human studies

BACKGROUND AND PURPOSE

Alveolar bone resorption after dental extraction frequently leads to situations in which long-term function and esthetic success of rehabilitations with dental implants is a challenge. Socket shield has been described as an alternative technique to maintain the alveolar ridge when placing immediate implants. The aim of this review is to evaluate the medium- and long-term clinical outcomes of the socket shield technique in human studies.

MATERIAL AND METHODS

This review was conducted according to PRISMA guidelines. An electronic search was conducted in four databases: (1) The National Library of Medicine (MEDLINE/PubMed) via Ovid; (2) Web of Science (WOS); (3) SCOPUS; and (4) Cochrane Central Register of Controlled Trials (CENTRAL). The Cochrane Collaboration tool, the Newcastle-Ottawa Quality Assessment Scale and The Joanna Briggs Institute Critical Appraisal tool were used to assess the quality of evidence in the studies reviewed.

RESULTS

Six articles were included in this review. The studies analysed showed lower rates of horizontal and vertical alveolar bone resorption, better maintenance of the buccal plate, less marginal bone loss and better esthetic results than simple placement of immediate implants. However, a lack of homogeneity was found in evaluation methods of the different outcomes, surgical procedures and prosthetic management.

CONCLUSIONS

Based on the results of this review, it is possible to suggest that socket shield technique could be a good alternative in terms of alveolar bone maintenance, marginal bone stability and aesthetic outcomes in immediate implant treatment. However, it is not possible to recommend this technique as an alternative treatment with the same long-terms predictability as conventional immediate implants.

Vertical ridge augmentation (VRA) with Ti-reinforced d-PTFE membranes or Ti meshes and collagen membranes: 1-year results of a randomized clinical trial

OBJECTIVES

The aim of this study was to evaluate hard and soft tissues around implants placed in posterior mandible 1 year after vertical ridge augmentation (VRA).

MATERIALS AND METHODS

40 patients with vertical defects were enrolled and treated according to the study protocol. Patients were randomly divided into two study groups: reinforced PTFE membranes (group A) and titanium meshes plus collagen membranes (group B). All patients received simultaneous implants which were evaluated after prosthetic restoration at baseline and after 1 year, using the following parameters: peri-implant bone levels (PBLs), interproximal bone peaks (IBPs), pocket probing depth (PPD), bleeding on probing (BoP), plaque index (mPI), gingival index (mGI), keratinized tissue thickness/width (tKT and wKT), and fornix depth (FD). Statistical analysis was performed to investigate any statistically significant differences and/or correlations (p = .05).

RESULTS

30 patients were completely followed up according to the study protocol. After 1 year, implants showed a change in PBL from 0.12 to 0.76 mm, with marginal bone loss of 0.67 and 0.61 mm for group A and group B, respectively, without significant differences (p > .9337). The estimated difference between treatments for the change from baseline in PBL was -0.05 (95% CI -0.27 to 0.16). Statistical analysis revealed strong correlations between PBL and IBP (p < .0001). However, no significant differences were observed for PPD, mPI, mGI, tKT, wKT, and FD (p > .05).

CONCLUSION

The results indicate that GBR treatment with titanium meshes plus collagen membranes (Group B) compared to reinforced PTFE membranes does not appear to be inferior or superior in terms of PBL change. In both groups, hard and soft tissues were stable after 1 year of follow-up, with a peri-implant bone loss less than 1.0 mm in the first year (study registered at ClinicalTrials.gov NCT04332679).

Immediate or delayed loading protocols for two-implant mandibular overdentures: A systematic review and meta-analysis of randomized controlled trials

STATEMENT OF PROBLEM

The immediate loading protocol for 2-implant mandibular overdentures has been widely reported. Nevertheless, the clinical effects reported in different articles are quite different.

PURPOSE

The purpose of this systematic review and meta-analysis of randomized controlled trials (RCTs) was to compare the clinical effects of immediate and delayed loading of 2-implant mandibular overdentures.

MATERIAL AND METHODS

The review followed the guidelines of Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA). PubMed, Cochrane Library, Web of Science, Embase, Scopus, ScienceDirect, CBM, CNKI, and Wan Fang databases were searched electronically for RCTs published before March 25, 2020. Two authors independently conducted literature screening, quality assessment, and data extraction. The outcomes of interest were implant failure rate, marginal bone loss (MBL), implant stability quotient (ISQ), periotest value (PTV), and patient satisfaction.

RESULTS

A total of 2498 unduplicated records were identified. After full-text analysis, 7 eligible RCTs were included. All studies were followed for at least 12 months, and the meta-analysis was based on this. The meta-analysis showed that the implant failure rate in the immediate group was higher than that in the delayed group, but there was no statistically significant difference (I²=0%; n=7; risk difference [RD]=0.03; 95% confidence interval [CI]=-0.01 to 0.08). The difference of MBL between immediate and delayed loading was not significant (I²=88%; n=6; mean difference [MD]=-0.04; 95% CI=-0.16 to 0.24). Because of the limited articles reporting on ISQ, PTV, and patient satisfaction, no quantitative analysis was conducted for these outcomes.

CONCLUSIONS

Although the implant failure rate was more likely to favor the delayed group, available evidence indicates no statistical difference in implant failure and marginal bone loss between immediate and delayed loading protocols.

Immediate orthodontic load on dental implants: an option for adult treatment

The demand for orthodontic treatment in adults has been increasing. However, these patients often require a multidisciplinary approach, due to the lack of posterior teeth, requiring additional anchorage. The skeletal anchorage by endosseous implants is an option, since they may be used later for prosthetic rehabilitation. The application of immediate load on these appliances for orthodontic movement may reduce the costs and total treatment time. This paper discusses the utilization of endosseous dental implants with immediate load for absolute anchorage for orthodontic movement, with later utilization for prosthetic rehabilitation.

Biological and mechanical complications of angulated abutments connected to fixed dental prostheses: A systematic review with meta-analysis

OBJECTIVES

To evaluate the biological and mechanical complications of angulated abutments on full-arch and partial jaw rehabilitations with a follow-up for at least 1 year.

METHODS

Electronic search was carried out in MEDLINE, EMBASE and Web of Science. Studies published between January 2000 and January 2019 were included. The quality of the included studies was assessed. The data extraction was focused on implant loss, marginal bone loss and mechanical complications, and meta-analyses were performed for marginal bone loss, mechanical complications and implant failure.

RESULTS

Nine studies, three prospective and six retrospective cohort studies were included. They reported on 797 patients that received 4127 implants. The total number of abutments was 4079 of which 1673 were angulated, and 2406 were straight. All abutments were prefabricated. Angulated abutments were associated with increased implant failure rates (two studies; RR = 7.30; 95% CI = 2.79-19.08) and an effect that was both statistically significant (P < .001) and clinically relevant. Three studies reported differentiated data for mechanical and technical complications at 1 year of follow-up, being mostly related to the retention screw while screw fracture. Angulated abutments were associated with a statistically significant increase in MBL 1 year after insertion compared to straight abutments (three studies; MD = 0.08 mm; 95% CI = 0.01-0.14 mm; P = .02), which might be, however, clinically negligible.

CONCLUSIONS

The prosthetic complications such as screw loosening and abutment loosening were frequent. After 1 year of follow-up, implants supporting angulated abutments yielded significantly more marginal bone loss than those supporting straight abutments.

Marginal bone loss 1 year after implantation: a systematic review for fixed and removable restorations

This systematic review analyses the difference of the mean marginal bone loss (MBL) 1 year after implantation depending on the fixation of the restoration. 889 publications on controlled clinical trials were identified, and based on inclusion and exclusion criteria, 22 studies were selected. Related to fixed restorations, the lowest MBL was 0.05±0.67 mm and the highest 1.37±0.5 mm. The MBL for removable restorations ranged from 0.13±0.35 mm to 1.03±0.65 mm. Three studies analyzed the MBL around implants of overdentures in the lower jaw. The estimate for this restoration type was 0.476 mm (95% CI: −0.305 to 1.258). 19 randomized controlled studies dealt with restorations which were fixed to the implants. The estimate for the mean MBL was 0.459 mm (95% CI: 0.325–0.593). There was a decrease in 1-year implant survival with an increase of 1 mm MBL (−0.083%; 95% CI: −0.179 to 0.0123; p=0.083) in fixed restorations. The difference in MBL between fixed and removable restorations was 0.363 mm (95% CI: −0.319 to 1.044; p=0.279). This systematic review indicates that implants with fixed and with removable restorations lead to comparable MBL.