Biomechanical and histologic basis of osseodensification drilling for endosteal implant placement in low density bone. An experimental study in sheep

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.

Ridge Architecture Preservation Following Minimally Traumatic Exodontia Techniques and Guided Tissue Regeneration

OBJECTIVE

To compare hard-tissue healing after 3 exodontia approaches.

MATERIALS AND METHODS

Premolars of dogs were extracted: (1) flapless, (2) flap, and (3) flap + socket coverage with polytetrafluoroethylene (dPTFE) nonresorbable membrane (flap + dPTFE). Animals were euthanized at 1 and 4 weeks. Amount of bone formation within socket and socket total area were measured.

RESULTS

Amount of bone formation revealed significant difference between 1 and 4 weeks; however, there was no differences among groups. Socket total area decreased after 4 weeks, and the flap + dPTFE group showed significantly higher socket total area. As a function of time and group, flap + dPTFE 4 weeks presented similar socket total area values relative to flap + dPTFE at 1 week, and significantly higher socket total area than flapless and flap. The histological sections revealed almost no bone formation within socket after 1 week, which increased for all groups at 4 weeks.

CONCLUSION

Socket coverage with polytetrafluoroethylene (dPTFE) membrane showed to effectively preserve bone architecture. Bone formation within sockets was not influenced by tooth extraction technique.

The effect of osseodensification and different thread designs on the dental implant primary stability

Background: It is difficult to achieve good primary stability of dental implants in soft bone, such as that in the posterior maxillae. Osseodensification (OD) burs, working in a non-subtractive fashion, condense the implant osteotomy bone in lateral direction and increase in the bone implant contact. Also, dental implants with deeper threads, and decreased thread pitch can increase initial bone implant anchorage.

Methods: This study utilized 48 custom-made machined surface dental implants that were 13 mm long, with a major diameter of 4.5 mm and a minor diameter of 3.5 mm, a thread pitch of 1 mm, a thread depth of 0.5 mm, and a 4 mm long cutting flute at the apex.  The implants were divided into 4 groups, each group was made of 12 implants with a different thread design; V-shaped, trapezoid, buttress, and reverse buttress. The implants were inserted in 4-mm thick cancellous bone slices obtained from the head of Cow femur bone. The ostoetomies were prepared by conventional drilling and by OD drilling. Each inserted implant was then tested for primary stability using the Periotest. The Periotest values (PTVs) for the implant stability were tabulated and analyzed using a chi square test at significance level p< 0.05.

Results: The results of this this study revealed no statistically significant difference between the Periotest readings for the implants in each category placed in either the OD or the regular osteotomies. However, it has been found that the implants placed in regular drilling ostoetomies had a significantly better primary stability than the implants placed in OD osteotomies.

Conclusions: It was concluded that OD is not necessary in situations where there is bone of good quality and quantity.

Atemporal osseointegration: Early biomechanical stability through osseodensification

Osseointegration, the direct functional and structural connection between device and bone is influenced by multiple factors such as implant macrogeometry and surgical technique. This study investigated the effects of osseodensification drilling techniques on implant stability and osseointegration using trabecular metal (TM) and tapered-screw vent (TSV) implants in a low-density bone. Six skeletally mature sheep were used where six osteotomy sites were prepared in each of the ilia, (n = 2/technique: Regular [R] (subtractive), clockwise [CW], and counterclockwise [CCW]). One TM and one TSV implant was subsequently placed with R osteotomy sites prepared using a conventional (subtractive) drilling protocol as recommended by the implant manufacturer for low density bone. CW and CCW drilling sites were subjected to osseodensification (OD) (additive) drilling. Evaluation of insertion torque as a function of drilling technique showed implants subjected to R drilling yielded a significant lower insertion torque relative to samples implanted in OD (CW/CCW) sites (p < 0.05). Histomorphometric analysis shows that the osseodensification demonstrates significantly greater values for bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO). Histological analysis shows the presence of bone remnants, which acted as nucleating surfaces for osteoblastic bone deposition, facilitating the bridging of bone between the surrounding native bone and implant surface, as well as within the open spaces of the trabecular network in the TM implants. Devices that were implanted via OD demonstrated atemporal biomechanical stability and osseointegration. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2516-2523, 2018.

The effect of osseodensification drilling for endosteal implants with different surface treatments: A study in sheep

This study investigated the effects of osseodensification drilling on the stability and osseointegration of machine-cut and acid-etched endosteal implants in low-density bone. Twelve sheep received six implants inserted into the ilium, bilaterally (n = 36 acid-etched, and n = 36 as-machined). Individual animals received three implants of each surface, placed via different surgical techniques: (1) subtractive regular-drilling (R): 2.0 mm pilot, 3.2 and 3.8 mm twist drills); (2) osseodensification clockwise-drilling (CW): Densah Bur (Versah, Jackson, MI) 2.0 mm pilot, 2.8, and 3.8 mm multifluted tapered burs; and (3) osseodensification counterclockwise-drilling (CCW) Densah Bur 2.0 mm pilot, 2.8 mm, and 3.8 mm multifluted tapered burs. Insertion torque was higher in the CCW and CW-drilling compared to the R-drilling (p < 0.001). Bone-to-implant contact (BIC) was significantly higher for CW (p = 0.024) and CCW-drilling (p = 0.006) compared to the R-drilling technique. For CCW-osseodensification-drilling, no statistical difference between the acid-etched and machine-cut implants at both time points was observed for BIC and BAFO (bone-area-fraction-occupancy). Resorbed bone and bone forming precursors, preosteoblasts, were observed at 3-weeks. At 12-weeks, new bone formation was observed in all groups extending to the trabecular region. In low-density bone, endosteal implants inserted via osseodensification-drilling presented higher stability and no osseointegration impairments compared to subtractive regular-drilling technique, regardless of evaluation time or implant surface. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 615-623, 2019.

Osseodensification - A novel approach in implant dentistry

Primary stability in dental implants is an essential factor for achieving successful osseointegration. Surgical procedure and bone quality are among the most common factors that affect primary stability. It is also crucial to achieve high-insertion torque which is important for obtaining primary stability. Maintaining sufficient bone bulk and density is essential to achieve necessary bone-to-implant contact for obtaining a biomechanically stable implant. A new concept for osteotomy called osseodensification (OD) has been at the forefront of changes in surgical site preparation in implantology. This relatively new concept with universally compatible drills has been proposed to help in better osteotomy preparation, bone densification, and indirect sinus lift and also achieve bone expansion at different sites of varying bone densities. This procedure has also shown improvement in achieving better implant primary stability and better osteotomy than conventional implant drills. A systematic review was undertaken to analyze if OD procedure had any advantages over conventional osteotomy on bone density and primary stability. An electronic database search was conducted in PubMed using keywords such as "OD," "implant primary stability," "implant bone density," and "implant osteotomy." A total of 195 articles were collected and subjected to screening using inclusion and exclusion criteria. A literature review was done, following which it was seen that the use of versah drills for bone OD resulted in undersized osteotomy compared to conventional drills. It also resulted in improved bone density and increase in percentage bone volume and bone-to-implant contact, thereby improving implant stability.

Increasing the Stability of Dental Implants: the Concept of Osseodensification

One of the most important factors that affect osseointegration is the primary stability of the implant. Dental implants inserted at the posterior region of the maxilla exhibit the lowest success rates as the low density bone in this area often jeopardize rigid fixation of the implant. Many surgical techniques have been developed to increase the primary stability of an implant placed in low density bone, such as bicortical fixation of the implant, undersized preparation of the implant bed and bone condensation by the use of osteotomes. A new promising technique, named osseodensification, has been recently developed that creates an autograft layer of condensed bone at the periphery of the implant bed by the aid of specially designed burs rotating in a clockwise and anti-clockwise direction. The purpose of this review is to emphasize that implant primary stability is strongly influenced by the surgical technique, to quote and briefly analyse the various surgical procedures laying weight to osseodensification procedure.

Osseodensification for enhancement of spinal surgical hardware fixation

Integration between implant and bone is an essential concept for osseous healing requiring hardware placement. A novel approach to hardware implantation, termed osseodensification, is described here as an effective alternative. 12 sheep averaging 65kg had fixation devices installed in their C2, C3, and C4 vertebral bodies; each device measured 4mm diameter×10mm length. The left-sided vertebral body devices were implanted using regular surgical drilling (R) while the right-sided devices were implanted using osseodensification drilling (OD). The C2 and C4 vertebra provided the t=0 in vivo time point, while the C3 vertebra provided the t=3 and t=6 week time points, in vivo. Structural competence of hardware was measured using biomechanical testing of pullout strength, while the quality and degree of new bone formation and remodeling was assessed via histomorphometry. Pullout strength demonstrated osseodensification drilling to provide superior anchoring when compared to the control group collapsed over time with statistical significance (p<0.01). On Wilcoxon rank signed test, C2 and C4 specimens demonstrated significance when comparing device pullout (p=0.031) for both, and C3 pullout tests at 3 and 6 weeks collapsed over time had significance as well (p=0.027). Percent bone-to-implant contact (%BIC) analysis as a function of drilling technique demonstrated an OD group with significantly higher values relative to the R group (p<0.01). Similarly, percent bone-area-fraction-occupancy (BAFO) analysis presented with significantly higher values for the OD group compared to the R group (p=0.024). As a function of time, between 0 and 3 weeks, a decrease in BAFO was observed, a trend that reversed between 3 and 6 weeks, resulting in a BAFO value roughly equivalent to the t=0 percentage, which was attributed to an initial loss of bone fraction due to remodeling, followed by regaining of bone fraction via production of woven bone. Histomorphological data demonstrated autologous bone chips in the OD group with greater frequency relative to the control, which acted as nucleating surfaces promoting new bone formation around the implants, providing superior stability and greater bone density. This alternative approach to a critical component of hardware implantation encourages assessment of current surgical approaches to hardware implantation.