Histomorphometrical assessment of vertical alveolar ridge augmentation using extracted tooth roots in the canine

Clinical outcomes following a combined vertical and horizontal alveolar ridge augmentation and two-stage implant placement using either autogenous tooth roots or autogenous bone blocks

AIM

To assess and compare the short-term clinical outcomes following a combined vertical and horizontal alveolar ridge augmentation and two-stage implant placement using either autogenous tooth roots (TR) or autogenous bone blocks (AB).

MATERIALS AND METHODS

A total of n = 27 patients (TR/AB: 13/14) exhibiting n = 31 implants (TR/AB: 14/17) were available for the analysis. Each subject had been allocated to a combined vertical and horizontal alveolar ridge augmentation using either (1) healthy TR (e.g., retained wisdom teeth), or (2) monocortical AB harvested from the retromolar area (i.e. external oblique line). Clinical parameters (e.g., bleeding on probing, BOP; probing pocket depth, PD; mucosal recession, MR) were recorded after a follow-up period of 16.03 ± 4.3 months following implant placement.

RESULTS

The survival rates amounted to 100% in both groups. TR and AB grafted sites were associated with similar changes in mean BOP (8.97 ± 27.73%; 11.90 ± 18.97%), PD (0.53 ± 0.49; 0.47 ± 0.67 mm), and MR (0.03 ± 0.13; 0.0 ± 0.02 mm) values. The incidence of peri-implant mucositis and peri-implantitis at the patient level amounted to 15.38% and 0.0% in the TR-, and 28.57% and 7.14% in the AB group.

CONCLUSIONS

Both surgical procedures were associated with peri-implant tissue health and stability on the short-term.

The clinical efficacy of autogenous dentin blocks prepared chairside for alveolar ridge augmentation: A systematic review and meta-analysis

OBJECTIVES

This systematic review aimed to evaluate the current evidence on the effectiveness of autogenous dentin block graft prepared chairside for alveolar ridge augmentation and compare its clinical outcomes to the main available grafting materials and techniques.

MATERIALS AND METHODS

Three databases were screened, including prospective clinical studies, utilizing autogenous dentin blocks for ridge augmentation, with at least 3 months of postoperative follow-up.

RESULTS

Eight articles were included, and four of them were meta-analyzed. Dentin blocks demonstrated similar vertical bone gain and significantly higher width gain, compared to bone blocks (WMD = 0.03, 95% CI -0.51 to 0.57, p = .92 and WMD = 1.34, 95% CI 0.57 to 2.12, p = .0007, respectively). Vertical and horizontal resorption were similar between the two groups (WMD = -0.36, 95% CI -0.91 to 0.18, p = .19, and WMD = -0.47, 95% CI -1.05 to 0.11, p = .11, respectively). Dentin blocks showed more incidences of postoperative complications, however, with no statistical significance (RR = 4.30, 95% CI 0.97 to 18.96, p = .054). The need for additional augmentation upon implant placement was also similar between both grafts (RR = 0.95, 95% CI 0.39 to 2.28, p = .90). Recorded incidences of graft exposure were low (2.27%), and no study stated surgical site infection.

CONCLUSION

Within its limitations, this study indicates that the autogenous dentin blocks prepared chairside could be a possible alternative to the other established bone augmentation techniques for staged ridge augmentation. Nevertheless, future studies are needed to confirm its efficacy and implant success/survival in sites grafted with this material.

Efficacy of autogenous tooth block for lateral ridge augmentation compared with autogenous bone block: A systematic review and meta-analysis

BACKGROUND

Autogenous tooth block (ATB) has been used as an alternative material for bone regeneration, but its efficacy compared with autogenous bone block (ABB) remains uncertain. The aim of this systematic review was to investigate and compare the clinical and histological performance of ATB and ABB grafts in lateral alveolar ridge augmentation (LARA).

METHODS

Electronic retrieval of MEDLINE, Embase, Cochrane Library (CENTRAL), Scopus, Web of Science, China national knowledge infrastructure, Wanfang data, SinoMed, and manual searching until July 2023 were used to identify controlled clinical trials employing ATB grafts in LARA. The identified reports included at least one of the following outcome variables: ridge width gain, graft resorption, postoperative complications, histology, and histomorphometry. Weighted or mean differences (MD), relative risk, and corresponding 95% confidence intervals (CI) were calculated. Descriptive analysis was applied to the qualitative statistics. The protocol followed the preferred reporting items for systematic reviews and meta-analyses statement and was prospectively registered in PROSPERO (CRD42023399611).

RESULTS

Four controlled clinical trials with 77 participants each using ATB and ABB grafts were included. Meta-analysis indicated that ATB grafts resulted in greater bone width (MD = 1.31, 95% CI [0.92, 1.71], P < .00001) and less graft resorption (MD = -0.71, 95% CI [-1.22, -0.21], P = .005) than ABB grafts on LARA. There was no statistical difference in postoperative complications between ATB and ABB grafts (relative risk = 0.81, 95% CI [0.32, 2.04], P = .66). Furthermore, the ATB grafts exhibited positive replacement resorption with alveolar bone for favorable signs of new bone activity on histology and histomorphometry.

CONCLUSION

Within the limitations of this study, ATB grafts could serve as an alternative material for ABB to support LARA. Further research with a longer follow-up period is required to verify these findings.

Efficacy of autogenous tooth roots for a combined vertical and horizontal alveolar ridge augmentation and staged implant placement. A prospective controlled clinical study

OBJECTIVES

To assess and compare the efficacy and safety of autogenous tooth roots (TRs) and autogenous bone blocks (ABs) for combined vertical and horizontal alveolar ridge augmentation and two-stage implant placement.

MATERIALS AND METHODS

A total of 28 patients in need of implant therapy and vertical ridge augmentation were allocated to parallel groups receiving either healthy autogenous tooth roots (e.g., retained wisdom teeth) (n = 14, n = 15 defects) or cortical autogenous bone blocks harvested from the retromolar area (n = 14, n = 17 defects). After 26 weeks of submerged healing, the clinical reduction in ridge height (RH) deficiency was defined as the primary outcome.

RESULTS

Both surgical procedures were associated with a similar mean reduction in RH deficiency values, amounting to 4.48 ± 2.42 mm (median: 4.25; 95% CI: 3.08-5.88) in the TR group and 4.46 ± 3.31 mm (median: 3.00; 95% CI: 2.54-6.38) in the AB group (p = .60, Mann-Whitney U-test). In all patients investigated, the reduction in RH deficiency values allowed for an adequate implant placement at the respective sites. The frequency of complications (e.g., soft tissue dehiscences) was low (TR: n = 4; AB: n = 0).

CONCLUSIONS

Up to staged-implant placement, both TR and AB grafts appeared to be associated with comparable efficacy and safety for combined vertical and horizontal alveolar ridge augmentation.

Acid Dentin Lysate Modulates Macrophage Polarization and Osteoclastogenesis In Vitro

Dentin prepared from extracted teeth is used as autograft for alveolar bone augmentation. Graft consolidation involves the acid lysis of dentin thereby generating a characteristic paracrine environment. Acid lysate of dentin is mimicking this environment. Acid dentin lysate (ADL) potentially targets hematopoietic cells thereby affecting their differentiation towards macrophages and osteoclasts; however, the question remains if ADL controls macrophage polarization and osteoclastogenesis. Here, we show that ADL reduced lipopolysaccharide (LPS)-induced macrophage polarization of the pro-inflammatory (M1) phenotype, indicated by attenuated Interleukin 1 (IL1), Interleukine 6 (IL6)and cyclooxygenase 2 (COX2) expression. This decrease in M1 macrophages was confirmed by the reduced phosphorylation and nuclear translocation of p65 in the LPS-exposed RAW 264.7 macrophages. Similarly, when RAW 264.7 macrophages were incubated with other agonists of Toll-like receptor (TLR) signaling e.g., FSL1, Polyinosinic-polycytidylic acid High Molecular Weight (Poly (1:C) HMW), Pam3CSK4, and imiquimod, ADL reduced the IL6 expression. We further show herein that ADL decreased osteoclastogenesis indicated by the reduced formation of multinucleated cell expressing cathepsin K and tartrate-resistant acid phosphatase in murine bone marrow cultures. Overall, our results suggest that acid dentin lysate can affect the differentiation of hematopoietic cells to M1 macrophage polarization and a decrease in osteoclastogenesis in bone marrow cultures.

Bone augmentation with autologous tooth shell in the esthetic zone for dental implant restoration: a pilot study

Objectives

To investigate the outcome and short-term follow-up of autogenous tooth shell (TS) grafting for bone augmentation in the esthetic zone, as well as stability and esthetics of implant-supported restoration.

Materials and methods

A total of 8 patients with 11 implants in 11 sites were enrolled in this study. All the horizontal and/or vertical bone defects in the esthetic zone were augmented by tooth shells, which were fixed laterally to the residual bone with osteosynthesis screws. The gap between the shell and residual bone was filled with Bio-Oss® granules. Four months after bone augmentation, dimensionally sufficient dental implants were inserted and implants-supported prostheses were made 3 months later. The esthetic outcome was evaluated by pink esthetic score (PES) and white esthetic score (WES) one year after prosthetic restoration. Horizontal ridge width (HRW) was assessed before and immediately after bone augmentation, as well as 4 and 19 months post-augmentation by radiography. The stability and absorption of TS grafts were evaluated at the 4th and 19th months post-augmentation.

Results

Though wound dehiscences occurred in 3 cases, secondary healings were obtained after TS modification and irrigation. The other 5 cases went through uneventful healing during the whole observation period. Radiographic examination showed that HRW was 8.01 ± 0.93 mm (median: 7.80, 95% CI 7.38, 8.64) 4 months after TS augmentation, which was statistically different compared to HRW (2.72 ± 1.73 mm) at the baseline. Mean HRW gain was 5.29 ± 2.03 mm (median: 4.60, 95% CI 3.92, 6.66). Three-dimensional bone volume in all the augmented sites was sufficient for dental implants insertion and prosthetic restoration. Follow-up of one year showed stable marginal bone around dental implants. The implant survival rate was 100%. HRW losses were 0.65 ± 0.43 mm (the 4th month) and 1.05 ± 0.54 mm (the 19th month) compared to HRW immediately after augmentation. The PES and WES of final prosthetic restorations were 8.09 ± 0.70 and 8.91 ± 0.54, respectively.

Conclusions

Autogenous tooth shell grafting is a reliable approach for bone augmentation in the esthetic zone for dental implant treatment, allowing for favorable stability and esthetic outcome of implant-supported prosthesis within the one-year follow-up period.

Clinical performance of tooth root blocks for alveolar ridge reconstruction

This systematic literature review set out to investigate the clinical outcomes of autogenous tooth root blocks used for ridge augmentation: survival rates, block resorption, implant survival, post-surgical complications, and histology findings. This review followed PRISMA guidelines. An automated search was made in four databases, supplemented by a manual search for relevant articles published before December 2020. The quality of evidence provided was assessed with the Newcastle-Ottawa Quality Assessment Scale and the Joanna Briggs Institute Critical Appraisal tool. Seven articles fulfilled the inclusion criteria and underwent analysis. The articles included a total of 136 patients, who received 118 autogenous tooth root blocks and 26 autogenous bone blocks showing block survival rates of 99.15% and 100%, respectively. Tooth root blocks presented a mean bone gain that was similar to autologous bone blocks but showed less resorption. The implant survival rate was 98.32% for autogenous tooth root blocks. Reconstruction of alveolar crests by means of autogenous tooth root blocks appears to be a satisfactory option for single-tooth gaps and low grades of bone atrophy in terms of the survival of the bone block and the implants placed subsequently. More research providing long-term data is needed to confirm these findings.

Manufacture and preliminary evaluation of acellular tooth roots as allografts for alveolar ridge augmentation

Alveolar ridge augmentation can be used to obtain appropriate alveolar ridge for dental implantation. A variety of bone graft materials including autogenous bone, allograft, xenograft, and alloplastic material are used in alveolar ridge augmentation. Autogenous tooth-derived bone graft material has received much attention for the past few years, because the structure and physicochemical characteristics of tooth are similar to those of bones. Compared to autogenous tooth, allogenic tooth has the advantage of extensive resources. However, the problem of cell-derived immunological rejection of allogenic tooth remains unresolved. In the present study, acellular tooth root (ATR) is obtained by an innovative combination procedure. The biocompatibility of ATR is assessed using cytotoxicity test, hemolysis test, intracutaneous reactivity test, and acute systemic toxicity test. Osseointegration is evaluated in vivo by implanting ATR into the rat tibia defect as an allograft material. The results show that the ATR has fine biocompatibility, and there is an osseointegration between ATR and bone bed at 8 weeks post operation. This study demonstrates that the ATR could be used in alveolar ridge augmentation as a kind of new tooth-derived bone graft material.

Animal models of vertical bone augmentation (Review)

Vertical bone augmentation is an important challenge in dental implantology. Existing vertical bone augmentation techniques, along with bone grafting materials, have achieved certain clinical progress but continue to have numerous limitations. In order to evaluate the possibility of using biomaterials to develop bone substitutes, medical devices and/or new bone grafting techniques for vertical bone augmentation, it is essential to establish clinically relevant animal models to investigate their biocompatibility, mechanical properties, applicability and safety. The present review discusses recent animal experiments related to vertical bone augmentation. In addition, surgical protocols for establishing relevant preclinical models with various animal species were reviewed. The present study aims to provide guidance for selecting experimental animal models of vertical bone augmentation.

Autogenous Dentin Block of A Non Restorable Wisdom Tooth for Localized Horizontal Ridge Augmentation: Radiographic and Histological Analysis: A Preliminary Case Report

INTRODUCTION

Tooth roots proved in different studies clinically and radiographically to be an alternative to autogenous bone. However, the histological evaluation of the tooth block following ridge augmentation is still missing. The aim of this case report was to evaluate histologically and radiographically the effect of autogenous dentin block (DB) to restore a horizontal ridge deficiency at a single tooth gap.

CASE PRESENTATION

A healthy 36-years old female patient presented with a missing lower first molar (30), after clinical and radiographic examination, the site showed a class III defect horizontal atrophy. The procedure performed was the surgical removal of the wisdom tooth (32), shaping and fixation of a separated DB at the defect site using an osteosynthesis screw. A cone beam computed tomography was performed immediately and 6 month following the surgery. During implant placement, a core biopsy specimen was retrieved, stored and prepared for histological evaluation. The radiographic analysis showed a horizontal width gain of about 4 mm. The histologic assessment revealed cortical bone formation at the buccal and lingual aspects between the tooth and the bone. During implant placement, the core biopsy exhibited a slight separation upon removal from the grafted side, at 6 month following implant placement, the implant was successfully osteointegrated.

CONCLUSION

DB was successfully used for horizontal alveolar ridge augmentation, thus allowing a prosthetically driven implant placement. More cases assessing implant survival and success are needed to confirm the results of this case report.

Microstructural volumetric analysis of vertical alveolar ridge augmentation using autogenous tooth roots

BACKGROUND

To volumetrically assess the bone microstructure following vertical alveolar ridge augmentation using differently conditioned autogenous tooth roots (TR) and second-stage implant placement.

MATERIALS AND METHODS

The upper premolars were bilaterally extracted in n = 4 beagle dogs and randomly assigned to either autoclavation (TR-A) or no additional treatment (TR-C). Subsequently, TR were used as block grafts for vertical alveolar ridge augmentation in both lower quadrants. At 12 weeks, titanium implants were inserted and left to heal 3 weeks. Microcomputed tomography was used to quantify bone volume per tissue volume (BV/TV), trabecular thickness (Tb.Th), and trabecular spacing (Tb.Sp) at vestibular (v) and oral (o) aspects along the implant and in the augmented upper half of the implant, respectively.

RESULTS

Median BV/TV [TR-C: 51.33% (v) and 70.42% (o) vs TR-A: 44.05% (v) and 64.46% (o)], Tb.th [TR-C: 0.22 mm (v) and 0.27 mm (o) vs TR-A: 0.23 mm (v) and 0.29 mm (o)] and Tb.Sp [TR-C: 0.26 mm (v) and 0.13 mm (o) vs TR-A: 0.29 μm (v) and 0.15 mm (o)] values were comparable in both groups.

CONCLUSION

Both TR-C and TR-A grafts were associated with a comparable bone microstructure within the grafted area.