Does the instrument used for the implant site preparation influence the bone–implant interface? A systematic review of clinical and animal studies

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.

Trephination-based autonomous robotic surgery for dental implant placement: A proof of concept

OBJECTIVES

To present a novel drilling protocol of trephine osteotomy technique for autologous bone grafting with simultaneous implant placement using an autonomous robotic system.

METHODS

The novel protocol consists of 1) preoperative procedures: marker fabrication and fixation, data acquisition, and preoperative planning; 2) intraoperative procedures: registration and calibration, and osteotomy and implant placement performed by an autonomous dental implant robot; 3) postoperative procedures: CBCT acquisition and accuracy assessment.

RESULT

The protocol was an effective method for implant osteotomy, with no reported intraoperative complications. The implant surgery was successfully completed, and autogenous bone was obtained. Meanwhile, the accuracy of implant placement was clinically acceptable, with minor deviations.

CONCLUSIONS

Trephination-based robotic surgery can be successfully implemented in implant osteotomy, which might replace freehand implant surgery and conventional drilling protocol. However, further clinical studies are necessary.

CLINICAL SIGNIFICANCE

The main finding of this case is a potential alternative for preserving autogenous bone during implant surgery.

Performance of a new implant system and drilling protocol-A minipig intraoral dental implant model study

AIM

A new implant system encompassing implants with a tri-oval cross-sectional design and a simplified site preparation protocol at low speed and no irrigation has been developed. The objective of this study was to assess the safety and efficacy of the new implant system using the minipig intraoral dental implant model.

METHODS

Eight Yucatan minipigs were included. Twelve weeks after extractions, four implants per animal were randomly placed and allowed to heal transmucosal for 13 weeks: two Ø3.5 × 10 mm implants with a back-tapered collar and circular cross-section (control) and two Ø3.5 × 11 mm implants with tri-oval collar and cross-section (test). MicroCT and histological analysis was performed.

RESULTS

Thirty-two implants were placed; one implant for the control group was lost. Histologically, BIC was higher in the test compared with the control group (74.1% vs. 60.9%, p < .001). At the platform level, inflammation was statistically significantly higher albeit mild in the test compared with the control group. No other significant differences were observed between groups. MicroCT analysis showed that bone-to-implant-contact (BIC) and trabecular thickness were statistically significantly higher for the test than the control group. Test group had significantly higher first BIC distance than controls on lingual sites.

CONCLUSIONS

The present study results support the safety and efficacy of the new dental implant system and simplified site preparation protocol; human studies should be carried out to confirm these findings.

A Comparative Assessment of Primary Implant Stability Using Osseodensification vs. Conventional Drilling Methods: A Systematic Review

Osseodensification is a novel biomechanical bone preparation technique that has been established to replace conventional bone drilling and therefore will optimize the implant site. The purpose of this systematic review was to compare the implant stability obtained by osseodensification drilling to those associated with conventional drilling techniques. An electronic search was performed in the PubMed, Scopus, EMBASE, Cochrane Oral Health Group, and Dentistry and Oral Science Source databases searched through Elton B. Stephens Company (EBSCO) for potentially relevant publications in the English language from January 2013 to December 2022. Randomized clinical trials (RCTs) and non-randomized studies of interventions (NRSIs), contrasting osseodensification drilling with conventional drilling, studies documenting implant stability quotient (ISQ), and studies reporting the immediate outcome and at least three months of follow-up after dental implant placement were included. Two independent investigators evaluated the quality of the reviewed studies to determine the risk of bias using the version 2 of Cochrane risk-of-bias (RoB) tool for RCTs (RoB 2) and RoB for NRSIs (ROBINS-I). Majority of the studies showed that bone density was significantly higher in the osseodensification group. The overall RoB for the NRSIs was reported to be low with respect to confounding, selection, classification, incomplete data, deviance from interventions, outcome evaluation, and selective reporting. The quality assessment of the RCT studies included in the review using the RoB 2 tool showed a high overall risk. The findings of the current review reveal that osseodensification drilling exhibited higher resonance frequency analysis (RFA) and ISQ values than conventional drilling protocols. Similarly, when osseodensification regions were contrasted with traditional drilling, bone density at the implant surface was augmented.

Effects of Osseodensification on Primary Stability of Cylindrical and Conical Implants-An Ex Vivo Study

Primary stability is an important factor for dental implant success. In the past years, a new method for bone site preparation was introduced, named osseodensification (OD). OD produces a condensation of the trabecular portion of the bone, increasing bone-to-implant contact and primary stability. This study aims to compare the effect of OD in cylindrical and conical implants to conventional instrumentation. A total of forty implants, divided into four groups, were placed in porcine tibia: cylindrical conventional (1a), cylindrical OD (1b), conical conventional (2a) and conical OD (2b). Each implant was measured for implant stability quotient (ISQ), insertion torque (IT) and removal torque (RT). Group 2b showed the higher values for each of the evaluated parameters; groups 1b and 2b showed better results than 1a and 2a, respectively. Regarding the IT and RT, group 1b achieved higher values than group 2a, but not for ISQ. The inter-group comparison showed significant difference between groups 1a vs 2a, 1a vs 2b and 1b vs 2b for ISQ and 1a vs 1b and 1a vs 2b for RT analysis. OD resulted in improved ISQ, IT and RT of both cylindrical and conical implants.

Changes in implant stability using different site preparation techniques: Osseodensification drills versus piezoelectric surgery. A multi-center prospective randomized controlled clinical trial

INTRODUCTION

Implant stability is influenced by bone density, implant design, and site preparation characteristics. Piezoelectric implant site preparation (PISP) has been demonstrated to improve secondary stability compared with conventional drilling techniques. Osseodensification drills (OD) have been recently introduced to enhance both bone density and implant secondary stability. The objective of the present multi-center prospective randomized controlled trial was to monitor implant stability changes over the first 90 days of healing after implant bed preparation with OD or PISP.

METHODS

Each patient received two identical, adjacent or contralateral implants in the posterior maxilla. Following randomization, test sites were prepared with OD and control sites with PISP. Resonance frequency analysis was performed immediately after implant placement and after 7, 14, 21, 28, 60, and 90 days. Implants were then restored with single screw-retained metal-ceramic crowns and followed for 12 months after loading.

RESULTS

Twenty-seven patients (15 males and 12 females; mean age 63.0 ± 11.8 years) were included in final analysis. Each patient received two identical implants in the posterior maxilla (total = 54 implants). After 1 year of loading, 53 implants were satisfactorily in function (one failure in test group 28 days after placement). Mean peak insertion torque (40.7 ± 12.3 Ncm and 39.5 ± 10.2 Ncm in test and control group, respectively) and mean implant stability quotient (ISQ) value at baseline (71.3 ± 6.9 and 69.3 ± 7.6 in test and control group, respectively) showed no significant differences between the two groups. After an initial slight stability decrease, a shift to increasing ISQ values occurred after 14 days in control group and after 21 days in test group, but with no significant differences in ISQ values between the two groups during the first 90 days of healing.

CONCLUSION

No significant differences in either primary or secondary stability or implant survival rate after 1 year of loading were demonstrated between implants inserted into sites prepared with OD and PISP.

A Retrospective Observational Study Assessing the Clinical Outcomes of a Novel Implant System with Low-Speed Site Preparation Protocol and Tri-Oval Implant Geometry

A novel, biologically friendly implant concept system introduces low-speed (50 rpm) site preparation instruments used without irrigation and a tri-oval, tapered implant designed to reduce stress on cortical bone without sacrificing mechanical stability. This retrospective, observational, multicenter study (clinicaltrials.gov NCT04736771) collected data from consecutive patients treated with at least one novel concept system implant to evaluate clinical outcomes after 1 year in function. The primary endpoint was a marginal bone level change (MBLC) from loading to 1 year, and secondary endpoints included implant survival and clinician feedback. Ninety-five patients (54 women and 41 men, mean age: 58 ± 12 years) were treated with 165 implants. For 94.5% of implants, site preparation was performed in two steps. The mean follow-up from implant insertion was 1.8 ± 0.2 years. Mean MBLC from implant loading to 1-year follow-up was +0.15 ± 0.85 mm (n = 124 implants). At the last follow-up, the implant survival rate was 98.0%. Clinician satisfaction with the novel concept system was high. The novel concept system offers an easy-to-use implant placement protocol, with most implants placed using two steps. The minimal bone remodeling and high survival rate observed across a variety of indications and treatment protocols demonstrate broad versatility and confirm the clinical benefits of this biologically friendly innovation.

SEM-EDX Analysis of Metal Particles Deposition from Surgical Burs after Implant Guided Surgery Procedures

The preparation of the implant site in guided surgery procedure takes place without irrigation, which could lead to increased friction of the drills with the formation and release of debris or metal particles. The presence of metal particles in the peri-implant tissue could represent a trigger for macrophage activity, bone resorption processes, and consequent implant loss. According to the guided surgical protocol, the study aimed to evaluate the presence of metal particles deposited during implant site preparation. Twenty-five adult porcine ribs from the same adult individual were chosen due to their trabecular bone structure, similar to facial bones. The samples were all 8 cm (length) × 3 cm (depth) × 2 cm (width) and were further subdivided to obtain 50 elements of 4 cm × 3 cm × 2 cm. Plexiglass was used to create structures such as surgical guides so that their function could be mimicked, and the guided implant site preparation sequence could be performed with them. The drill kit used in this study is a guided surgery drill kit characterized by high wear resistance, high yield strength, and good corrosion resistance. This same kit was used 50 times in this way to prepare 50 different implant sites and evaluated at different edges and number of preparation (T0-neutral edge, T1-1 full preparation, T2-10, T3-20, T4-30, T5-40, and T6-50) by SEM-EDX to assess the presence of any metal deposition. The presence of metal residues in the implant site increased according to the cycles of use of the drills. We have observed that in the first three groups, there is no presence of metals. This is evident in groups T3 and T4. Finally, the presence of metal residues becomes significant in the study’s last two groups of samples. The study highlighted how the lack of irrigation in the work site leads the deposition of metal particles and in addition to a reduction in the efficiency of the drills, resulting in less precise cutting, altering the shape of the prepared site, and, lastly, reducing the primary stability of the implants.

Healing at implants installed in osteotomies prepared either with a piezoelectric device or drills: an experimental study in dogs

OBJECTIVE

To compare osseointegration and marginal bone level at implants placed in osteotomies prepared with either conventional drills or a piezoelectric device.

MATERIAL AND METHODS

Three months after the extraction of all mandibular premolars and first molars, two recipient sites were selected. The osteotomies were randomly prepared with either conventional drills (drill sites) or a piezoelectric device (piezoelectric sites). Implants were installed and a submerged healing was allowed. The animals were euthanized in groups of six after 4 and 8 weeks of healing. Biopsies were obtained for histological preparation. Coronal level of osseointegration (bone level) and bone-to-implant contact percentage (BIC%) were evaluated.

RESULTS

After 4 weeks of healing, the bone level was 0.6 ± 0.9 mm for the piezoelectric sites and 1.6 ± 0.7 mm for the drill sites (p = 0.173). After 8 weeks, the respective measures were 0.9 ± 0.3 mm and 1.0 ± 1.1 mm (p = 0.917). After 4 weeks of healing, a new bone apposed onto the implant surface was found at fractions of 54.9 ± 6.7% and 55.1 ± 16.6% for the piezoelectric and the drill sites, respectively (p = 0.674). The respective total bone fractions, including new and old bone, was 64.0 ± 4.8% and 63.4 ± 20.4% (p = 0.917). After 8 weeks, a new bone increased to 67.4 ± 6.7% and 62.9 ± 12.5% for the piezoelectric and the drill sites, respectively (p = 0.463). The respective total bone fractions were 70.4 ± 5.5% and 67.8 ± 12.1% (p = 0.753).

CONCLUSIONS

The use of a piezoelectric device for implant site preparation is a safe procedure that allows a proper integration since the early periods of healing similar to that observed using conventional drills.

Implant stability and survival rates of a hydrophilic versus a conventional sandblasted, acid-etched implant surface: Systematic review and meta-analysis

BACKGROUND

Modifying the implant surface via enhancing the wettability (hydrophilicity) improves osseointegration, reducing the healing period. In this study, the authors aimed to evaluate the stability and survival rates of implants with a hydrophilic surface compared with those with a sandblasted, acid-etched surface.

TYPES OF STUDIES REVIEWED

The included studies (randomized controlled trials) were identified through searches of PubMed, ScienceDirect, and Cochrane Library databases without date of publication restrictions. Quality assessment was performed using the Cochrane Collaboration tool. For primary outcome, confidence intervals were set at 95%; weighted means across the studies were calculated using a fixed-effects model or risk ratios and their 95% confidence intervals for secondary outcome.

RESULTS

The authors included 5 randomized controlled trials (246 dental implants) in the systematic review, which compared a hydrophilic with conventional sandblasted, acid-etched implant surface. The implant stability (primary outcome) was measured at baseline and 3, 6, and 8 weeks, and implant survival rates were measured as a secondary outcome. Overall, compared with the control groups, no clinically significant differences in implant stability or survival rates were identified for the hydrophilic surface groups.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

The results did not show any clinically significant effect of a hydrophilic surface on improving implant stability or survival rates. However, these findings must be analyzed carefully owing to the limitations of this review, such as the small samples size and some differences among the included studies.

The effect of osseodensification on implant stability and bone density: A prospective observational study

Background

The aims of this study were to evaluate the effect of implant site preparation in low-density bone using osseodensification method in terms of implant stability changes during the osseous healing period and peri-implant bone density using CBCT.

Material and Methods

This prospective observational clinical study included 24 patients who received 46 dental implants that were installed in low-density bone using the osseodensification method. CBCT was used to measure the bone density pre- and postoperatively and implant stability was measured using Periotest® immediately after implant insertion and then after 6 weeks and 12 weeks postoperatively. The data were analyzed using paired t-test and the probability value <0.05 was considered statistically significant.

Results

Of the 46 implants, 43 were osseointegrated making the early survival of the implants 93.5%. There was a significant increase in bone density postoperatively; 337.6 ±182.9 compared to 265.3 ±173.9 Hounsfield units preoperatively. The primary implant stability was -2.7 ± 2.13 Periotest values (PTV), at the 6th week it decreased significantly (p<0.0001) to become 0.7 (± 4) PTV, and at the 12th week (secondary stability) it increased significantly (p<0.0001) to become -2.1 (± 2.8) PTV. The difference between primary and secondary stability was statistically non-significant (p=0.0814).

Conclusions

Osseodensification resulted in high primary stability and increased peri-implant bone density but it did not prevent the implant stability drop during the first 6 weeks after insertion of implants.

Key words:Osseodensification, implant stability, low-density bone.

A New Site Preparation Protocol That Supports Bone Quality Evaluation and Provides Predictable Implant Insertion Torque

When preparing an implant site, clinicians often base their assessment of the bone on subjective tactile and visual cues. This assessment is used to plan the surgical procedure for site preparation, including how many drilling steps will be used. The subjective nature of bone evaluation, consequently, results in poor reproducibility and may lead to under or over preparation of the site. Recently, an unconventional site preparation protocol was developed in which the decision of which instruments to use is dictated by insertion torque of the novel site preparation instrument (OsseoShaper^™, Nobel Biocare AB, Gothenburg, Sweden). The aim of this study was to quantify the correlation of the site preparation torques of the new instrument with bone density and maximum implant insertion torques. In vitro and in vivo data showed strong linear correlation between site preparation torque and density and resulted in reliable implant insertion torques, respectively. From our analysis, we conclude that this new instrument and protocol has the potential to eliminate the need for additional intraoperative bone evaluation and may reduce the risk of inadequate preparation of the site due to the ability to serve as a predictor of the final implant insertion torque.

Under-Drilling versus Hybrid Osseodensification Technique: Differences in Implant Primary Stability and Bone Density of the Implant Bed Walls

The goal of this study was to evaluate the effects of two implant bed preparation techniques on the implant primary stability (IPS) and the bone density of the implant site. We completed 40 implant bed osteotomies in pig ribs using two techniques: osseodensification (OD) plus under-drilling (UD) with universal osseodensification drills (Test A), and under-drilling alone with drills of the same implant system (Test B). Implants with a 4.1 mm diameter and 10 mm length were inserted, and the IPS was evaluated with three methods: (insertion torque (IT), periotest (PTV), and resonance frequency analysis (RFA). The bone density was evaluated using micro-computed tomography. ANOVA and Tukey’s post-hoc test were used for comparison of the IPS values, and Kruskal–Wallis was used to evaluate the bone density. Statistical significance was set at p < 0.05. The tested B technique (UD) achieved a higher IPS compared to the Test A technique (OD + UD) for all the evaluation methods (p < 0.05). Bone density was higher at the apical and middle region in Test A compared to Test B and control sites (p < 0.05). We concluded that although the bone density increased with the hybrid OD technique with universal drills, implant beds prepared with UD using drills with geometry similar to that of the implant are more efficient at increasing IPS values.

Does the Drilling Technique for Implant Site Preparation Enhance Implant Success in Low-Density Bone? A Systematic Review

PURPOSE

The objective of this systematic review was to investigate the possible association between the drilling technique and proper implant integration and survival in areas with low bone density.

MATERIALS AND METHODS

An electronic search using the MEDLINE/PubMed database was performed including studies published up to April 2018. Animal and clinical studies that evaluated the association between the drilling technique and proper implant integration and survival in low-density bone were included.

RESULTS

Fifteen studies met the inclusion criteria, including 7 experimental and 8 clinical. Undersized, osteotome, Piezosurgery, and osseodensification drilling were the 4 techniques found in the literature to enhance osseointegration of implants in low-density bone. Owing to the methodological variation, meta-analysis was not performed. The 4 drilling protocols were effective in increasing primary stability, but the long-term outcome is comparable with that of the conventional surgical drilling protocol.

CONCLUSION

There is weak evidence suggesting that any of the previously mentioned surgical techniques could enhance successful osseointegration and survival of the implants placed in low-density bone.