Microstructural volumetric analysis of lateral ridge augmentation using differently conditioned tooth roots

Lateral Alveolar Ridge Augmentation with Autogenous Tooth Roots and Staged Implant Placement-5-Year Follow-Up Case Series

Background/Objectives: Alveolar bone augmentation before implant placement is a safe and effective treatment option for the reconstruction of a deficient alveolar ridge. According to recent research, permanent teeth have been used as bone graft materials, with studies confirming their clinical and histological results. This study aimed to evaluate the efficacy of alveolar ridge augmentation with autogenous tooth roots and staged implant placement, and peri-implant tissue stability in augmented sites. Methods: A total of 20 augmentations with autogenous tooth roots on mandibular alveolar ridges in 15 patients were performed. After 6 months, the ridge width (RWa) and ridge width gain (RWg) were measured. Titanium dental implants were placed in grafted sites and loaded 10 weeks after placement. Clinical parameters (bleeding on probing-BOP; probing depth-PD; mucosal recession-MR; and clinical attachment level-CAL) were assessed 2 months (T1), 3 years (T2), and 5 years (T3) after implant loading. Results: The mean RWa was 6.71 ± 0.74 mm, and the RWg was 3.15 ± 0.54 mm, respectively. No statistically significant differences were observed for clinical parameters (BOP, PD, MR, and CAL) among different time points (p > 0.05). Conclusions: Autogenous tooth roots represent a viable solution for alveolar ridge augmentation and implant placement, providing a stable environment for peri implant tissues.

Comparative Effectiveness of an Autologous Dentin Matrix for Alveolar Ridge Preservation

An urgent issue is the preservation or reconstruction of the volume of bone tissue in planning and surgical treatment in the fields of medicine, such as traumatology, orthopedics, maxillofacial surgery and dentistry. After tooth extraction, resorption of the bone tissue of the alveolar crest of the jaws occurs, which must either be further eliminated by performing additional operations or using osteoplastic material for socket preservation at the extraction stage. Background and Objectives: The aim of the study was a comparative analysis of various osteoplastic materials used to preserve the volume of bone tissue in the preimplantation period. Materials and Methods: As part of the study, 80 patients were treated, who underwent socket preservation using xenografts, plasma enriched with growth factors, an autologous dentin matrix (ADM) and hydroxyapatite. Results: The results of the treatment 16 weeks after removal were comprehensively analyzed using a morphometric analysis of the bone's volume, cone beam tomography and morphological examination of burr biopsy specimens, as well as by determining the stability of the installed implant at different stages of treatment. Conclusions: The lowest level of bone tissue resorption according to the CBCT data was noted in the ADM and xenograft groups. It should be noted that the use of osteoplastic material in jaw surgery when reconstructing alveolar defects is an essential procedure for preventing the atrophy of bone tissue.

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.

Dentin Particulate for Bone Regeneration: An In Vitro Study

The aim of this in vitro study was to investigate the commitment and behavior of dental pulp stem cells (DPSCs) seeded onto two different grafting materials, human dentin particulate (DP) and deproteinized bovine bone matrix (BG), with those cultured in the absence of supplements. Gene expression analyses along with epigenetic and morphological tests were carried out to examine odontogenic and osteogenic differentiation and cell proliferation. Compressive testing of the grafting materials seeded with DPSCs was performed as well. DPSC differentiation into odontoblast-like cells was identified from the upregulation of odontogenic markers (DSPP and MSX) and osteogenic markers (RUNX2, alkaline phosphatase, osteonectin, osteocalcin, collagen type I, bmp2, smad5/8). Epigenetic tests confirmed the presence of miRNAs involved in odontogenic or osteogenic commitment of DPSCs cultured for up to 21 days on DP. Compressive strength values obtained from extracellular matrix (ECM) synthesized by DPSCs showed a trend of being higher when seeded onto DP than onto BG. High expression of VEGF factor, which is related to angiogenesis, and of dentin sialoprotein was observed only in the presence of DP. Morphological analyses confirmed the typical phenotype of adult odontoblasts. In conclusion, the odontogenic and osteogenic commitment of DPSCs and their respective functions can be achieved on DP, which enables exceptional dentin and bone regeneration.

Clinical efficacy of autogenous dentin grafts with guided bone regeneration for horizontal ridge augmentation: a prospective observational study

The aim of this study was to evaluate the efficacy of autogenous dentin grafts with guided bone regeneration (GBR) for horizontal ridge augmentation. Nineteen patients with dentition and bone defects in whom tooth/teeth extraction was indicated were recruited. Autogenous teeth were prepared, fixed on the buccal sides of the defects, and covered with bone powder and resorbable membranes before implantation. The horizontal bone mass at 0 mm (W1), 3 mm (W2), and 6 mm (W3) from the alveolar crest was recorded using cone beam computed tomography, before, immediately after, and 6 months after dentin grafting. All adverse effects were recorded. The implant stability quotient (ISQ) was measured 6 months after implantation. Twenty-eight implants were placed 6 months after dentin grafting. At this time point, the bone mass was 4.72 ± 0.72 mm (W1), 7.35 ± 1.57 mm (W2), and 8.96 ± 2.38 mm (W3), which was significantly different from that before the surgery (P < 0.05). The bone gain was 2.50 ± 0.72 mm (W1), 4.10 ± 1.42 mm (W2), and 4.56 ± 2.09 mm (W3). No soft tissue dehiscence or infection was observed. Overall, 26.3% of the patients experienced severe pain after dentin grafting. The ISQ was 78.31 ± 6.64 at 6 months after implantation. Autogenous tooth roots with GBR might be effective for horizontal ridge augmentation. This technique could be an alternative to augmentation using autogenous bone grafts.

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.

Proteomic and genomic analysis of acid dentin lysate with focus on TGF-β signaling

Particulate autologous tooth roots are increasingly used for alveolar bone augmentation; however, the proteomic profile of acid dentin lysate and the respective cellular response have not been investigated. Here we show that TGF-β1 is among the 226 proteins of acid dentin lysate (ADL) prepared from porcine teeth. RNA sequencing identified 231 strongly regulated genes when gingival fibroblasts were exposed to ADL. Out of these genes, about one third required activation of the TGF-β receptor type I kinase including interleukin 11 (IL11) and NADPH oxidase 4 (NOX4). Reverse transcription-quantitative polymerase chain reaction and immunoassay confirmed the TGF-β-dependent expression of IL11 and NOX4. The activation of canonical TGF-β signaling by ADL was further confirmed by the phosphorylation of Smad3 and translocation of Smad2/3, using Western blot and immunofluorescence staining, respectively. Finally, we showed that TGF-β activity released from dentin by acid lysis adsorbs to titanium and collagen membranes. These findings suggest that dentin particles are a rich source of TGF-β causing a major response of gingival fibroblasts.

Retrospective Study: Lateral Ridge Augmentation Using Autogenous Dentin: Tooth-Shell Technique vs. Bone-Shell Technique

In the literature, autogenous dentin is considered a possible alternative to bone substitute materials and autologous bone for certain indications. The aim of this proof-of-concept study was to use autogenous dentin for lateral ridge augmentation. In the present retrospective study, autogenous dentin slices were obtained from teeth and used for the reconstruction of lateral ridge defects (tooth-shell technique (TST): 28 patients (15 females, 13 males) with 34 regions and 38 implants). The bone-shell technique (BST) according to Khoury (31 patients (16 females, 15 males) with 32 regions and 41 implants) on autogenous bone served as the control. Implants were placed simultaneously in both cases. Follow-up was made 3 months after implantation. Target parameters during this period were clinical complications, horizontal hard tissue loss, osseointegration, and integrity of the buccal lamella. The prosthetic restoration with a fixed denture was carried out after 5 months. The total observation period was 5 months. A total of seven complications occurred. Of these, three implants were affected by wound dehiscences (TST: 1, BST: 2) and four by inflammations (TST: 0, BST: 4). There were no significant differences between the two groups in terms of the total number of complications. One implant with TST exhibited a horizontal hard tissue loss of 1 mm and one with BST of 0.5 mm. Other implants were not affected by hard tissue loss. There were no significant differences between the two groups. Integrity of the buccal lamella was preserved in all implants. All implants were completely osseointegrated in TST and BST. All implants could be prosthetically restored with a fixed denture 5 months after augmentation. TST showed results comparable to those of the BST. Dentin can therefore serve as an alternative material to avoid bone harvesting procedures and thus reduce postoperative discomfort of patients.

Tooth shell technique: A proof of concept with the use of autogenous dentin block grafts

BACKGROUND

Autogenous bone block graft is considered the gold standard for lateral bony defects. Dentin has been identified to be a suitable autogenous bone graft material due to its structural and chemical similarities to the alveolar bone.

METHODS

This proof of concept study describes the clinical application of the tooth shell technique in 24 sites with 27 implants of 22 patients. A tooth shell was fixed laterally to the defect with microscrews. Distance between the shell and the residual bone was filled with particulate remnants of the tooth root. Implant was inserted simultaneously. Cone beam computed tomography was done after implant insertion (T1) and 3 months later at time of implant exposure (T2). Target parameters were biological complications and the resorption of hard tissue graft.

RESULTS

Even though a graft exposure occurred in one case (4.5% on patient-level), all implants showed enough implant stability and were able to be loaded. At T2, the evaluation of the X-rays showed no case with hard tissue loss at the mesial or distal implant shoulder. All implants were completely osseointegrated.

CONCLUSIONS

The tooth shell technique showed promising results for the reconstruction of lateral alveolar crest defects. It may be considered to serve as an alternative material to avoid bone harvesting procedures.

Microstructural volumetric analysis of the jaw following dental implantation under systemic bisphosphonate delivery: An in vivo and ex vivo rat study

BACKGROUND

Because of bisphosphonate medication, dental implantation with a subsequent infection poses a relevant risk factor to suffer from medication-related osteonecrosis of the jaw. This rat study evaluated different implant materials under systemic bisphosphonate delivery using micro-computed tomography (μCT) images.

METHODS

Fifty-four rats were randomly allocated into a control group 1, test group 2 with intravenous drug application of zoledronic acid and test group 3 with a subcutaneous application of alendronic acid. After 4 weeks of drug delivery, the first molar on each side of the upper jaw was extracted, and either a zirconia or a titanium implant was immediately inserted. Radiological examinations at four timepoints before the operation, 1 week later, 6 weeks later and after 12 weeks of follow up included μCT measurements of the in vivo peri-implant bone loss. μCT measurements of the ex vivo peri-implant bony structure after 12 weeks follow-up covered the bone mineral density, -volume, -trabecular thickness and -separation.

RESULTS

Both test groups showed a significant increase in bone loss over time (P < 0.05). The clinical observations of exposed bone revealed that most cases occurred under alendronic acid delivery. Exposed bone was recorded only in the test groups around both titanium and zirconia implants. Regarding the peri-implant bony structure, no significant differences were found between both materials.

CONCLUSIONS

Systemic bisphosphonate delivery led to increased peri-implant bone loss over time after immediate implant insertion. In terms of bone resorption and bone quality parameters, no implant material was superior to the other.

Cleaning Teeth Reduces the Inflammatory Response of Macrophages to Acid Dentine Lysate

Particulate autogenous tooth roots are used for alveolar bone augmentation surgery; however, dental plaque may provoke an inflammatory response that may counteract the desired graft consolidation process. Traditional mechanical cleaning of extracted teeth may be of support to lower a possible inflammatory response of the autograft. To test this assumption, extracted porcine teeth were left either uncleaned or underwent mechanical cleaning with a toothbrush and toothpaste before being fragmented and subjected to acid lysis, termed as unclean acid dentine lysate (ucADL) and clean acid dentine lysate (cADL), respectively. The inflammatory responses of murine macrophage RAW 264.7 cells being exposed to the respective acid dentine lysates were evaluated at the level of inflammatory gene expression and IL6 immunoassays. We report here that acid lysates obtained from uncleaned teeth provoked a robust increase in IL1β, IL6, and COX2 in RAW 264.7 cells. The mechanical removal of dental plaque significantly reduced the inflammatory response. Consistently, Limulus tests revealed that tooth cleaning lowers the presence of endotoxins in dentine lysates. To further prove the involvement of endotoxins, a toll-like receptor 4 (TLR4) inhibitor TAK242 was introduced. TAK242 abolished the inflammatory response provoked by acid lysates obtained from uncleaned teeth in RAW 264.7 cells. Moreover, nuclear translocation and phosphorylation of the TLR4 downstream NFκB-p65 were attenuated at the presence of cleaned versus uncleaned dentine lysates. Taken together, our data support the importance of dental plaque removal of teeth being extracted for alveolar bone augmentation surgery.

Ischial tuberosity: new donor site for bone grafts in animal cleft research

In the context of cleft repair in animal research in rat models, different areas can be used for bone grafting. The aim of the present study was to present the tuberosity of the ischium as a new donor site and to evaluate its quality in relation to an artificial alveolar cleft. Four weeks after creating experimental alveolar clefts in seven Wistar rats, the repair was performed in the now twelve-week-old male animals using bone blocks grafted from the ischial tuberosity. Two days before surgery and two as well as twenty-eight days after surgery, microCT scans were performed, and the grafted bone blocks were analyzed regarding height, width, thickness, and volume. Additionally, bone mineral density (BMD) and bone volume fraction (BV/TV) were measured in the repaired cleft. The mean bone volume of the graft was about 19.77 ± 7.77mm³. Immediately after jaw reconstruction the BMD and BV/TV were about 0.54 ± 0.05 g/cm³ and 54.9 ± 5.07% for the transplant and about 1.13 ± 0.08 g/cm³ and 94.5 ± 3.70%, respectively, for the surrounding bone. Four weeks later the BMD and BV/TV were about 0.57 ± 0.13 g/cm³ and 56.60 ± 13.70% for the transplant and about 11.17 ± 0.07 g/cm³ and 97.50 ± 2.15%, respectively, for the surrounding bone. A hip fracture was found in four of the animals after surgery. The ischial tuberosity offers large bone blocks, which are sufficient for cleft repair in the rat model. However, the bone quality regarding BMD and BV/TV is less compared with the surrounding bone of the alveolar cleft, even after a period of 4 weeks, despite recognizable renovation processes.

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.

Short-term outcomes of staged lateral alveolar ridge augmentation using autogenous tooth roots. A prospective controlled clinical study

OBJECTIVES

To assess the short-term clinical outcomes of lateral alveolar ridge augmentation using autogenous tooth roots (TR) and autogenous bone blocks (AB).

MATERIAL AND METHODS

A total of n = 23 patients (23 implants) were available for the analysis. Each subject was allocated to lateral ridge augmentation using either (a) healthy autogenous tooth roots (e.g., retained wisdom or impacted teeth; n = 13) or (b) cortical autogenous bone blocks harvested from the retromolar area (n = 10). Clinical parameters (e.g., bleeding on probing-BOP, probing pocket depth-PD, mucosal recession-MR, clinical attachment level-CAL) were recorded at (V8) and after 26 ± 4 weeks (V9) of implant loading.

RESULTS

TR and AB groups were associated with comparable (p > 0.05) changes in mean BOP (-23.0 ± 34.3%; -11.75 ± 24.9%), PD (-0.03 ± 0.14 mm; -0.1 ± 0.29 mm), MR (0.0 ± 0.0 mm; 0.0 ± 0.0 mm) and CAL (-0.03 ± 0.14 mm; -0.1 ± 0.29 mm) values. The regression analysis failed to reveal any significant correlations between changes in BOP and PD values and the initial as well as the ridge width measured at 26 weeks.

CONCLUSIONS

TR and AB were associated with comparable clinical short-term outcomes.