Human dentin materials for minimally invasive bone regeneration: Animal studies and clinical cases.

OBJECTIVES: Bone, platelet concentrate, and tooth-derived dentin/cementum have been used as autologous materials in regenerative medicine Dentin materials were first recycled in 2002 for bone regeneration in humans, although bone autografts were noted in the 19th century, and auto-platelet concentrates were developed in 1998. Dentin/cementum-based material therapy has been applied as an innovative technique for minimally invasive bone surgery, while bone autografts are associated with donor site morbidity. METHODS: In October 2021, PubMed, Google Scholar, Scopus, and the Cochrane Library databases from 1980 to 2020 were screened. RESULTS: The demineralized dentin/cementum matrix (DDM) had better performance in bone induction and bone regeneration than mineralized dentin. CONCLUSIONS: Unlike cell culture therapy, DDM is a matrix-based therapy that includes growth factors. A matrix-based system is a realistic and acceptable treatment, even in developing countries. The aim of this review was to summarize the evidence related to both animal studies and human clinical cases using human dentin materials with a patch of cementum, especially DDM.

Utilización de dentina autógena para relleno del gap en el implante inmediato postextracción: a propósito de un caso clínico con seis meses de seguimiento / Autogenous dentin graft in the immediate post-extractive implant gap: six-month follow up of a clinical report

Introducción: las extracciones dentarias producen una reabsorción horizontal y vertical de la cresta alveolar, que se puede minimizar con algunas técnicas quirúrgicas, como la colocación de implantes inmediatos post-extracción, asociados al empleo de biomateriales. Caso clínico: se presenta el caso clínico de una mujer de 48 años, que acudió a consulta presentando dolor intenso en la zona del incisivo lateral superior izquierdo, asociado a una profundidad de sondaje de 12 mm. Se realizó la exodoncia del 2.2, y la colocación de un implante inmediato post-extracción, utilizando la dentina de la raíz extraída, para rellenar el gap entre el implante y la cortical vestibular, mostrando buenos resultados clínicos y radiográficos a los 6 meses tras la intervención. Discusión: aunque en la actualidad se utilizan multitud de biomateriales para reducir la reabsorción ósea en los implantes inmediatos post-extracción, ninguno de ellos parece tener mejores resultados que el resto, suponiendo en este sentido la dentina autógena una alternativa útil al tratarse de un material autólogo, con buenas tasas de aceptación por parte de los pacientes, y teniendo unas propiedades adecuadas de osteoconducción y osteoinducción.Conclusiones: la dentina autógena presenta buenos resultados clínicos y radiográficos para rellenar el gap en implantes inmediatos post-extracción (AU)

Introduction: Tooth extraction produces an horizontal and vertical resorption of the alveolar ridge, which can be reduced by many surgical techniques, such as immediate post-extractive implants, in combination with bone substitutes. Clinical case: A clinical case of a 48-year-old woman is presented, who went to dental clinic referring pain in her upper lateral incisor, associated to high probing depth. An immediate post extractive implant was placed, employing autogenous dentin from the root extracted, to fill the gap between the implant and the buccal plate, showing good clinical and radiographic evolution 6 months after surgery. Discussion: Although nowadays there are different bone substitutes to reduce bone resorption when immediate implants are placed, they have similar results, becoming autogenous dentin an useful alternative, which is an autologous material, with good patient acceptation rates and osteoconductive and osteoinductive properties.Conclusion: Autogenous dentin shows promising clinical and radiographical results when it is used to fill the gap in the post-extractive immediate implant (AU)

Regeneración ósea guiada con dentina autógena tras la exodoncia de un premolar retenido en posición invertida: evaluación a 4 meses de un caso clínico / Guided bone regeneration with autogenous dentin after extraction of an impacted bicuspidin inverse position: 4-month evaluation of a clinical case

Introducción: el empleo de técnicas regenerativas tras la extracción de dientes retenidos ha mostrado su eficacia con diversos materiales de regeneración, al asociarse al empleo de membranas, pero en los últimos años se ha descrito el empleo de dentina autógena en procedimientos de regeneración ósea, mostrando unos resultados favorables. Caso clínico: se presenta un caso clínico de una mujer de 20 años, sin antecedentes médico-quirúrgicos de interés, que acudió a consulta remitida por su ortodoncista, para la extracción de un premolar maxilar retenido, en posición invertida. Tras la extracción del premolar y del tercer molar inferior retenidos, se obtuvo dentina procedente de ambos, para la regeneración ósea guiada del defecto resultante de la extracción del premolar, realizando revisiones a la semana y a los 4 meses de la intervención. Conclusiones: la dentina autógena demuestra ser un biomaterial biocompatible, adecuado para procedimientos de regeneración ósea guiada, tras la extracción de dientes retenidos, como alternativa a otros biomateriales. (AU)

Introduction: regenerative bone techniques after impacted teeth extraction have shown to be effective with different materials, when used in conjunction with membranes, but in the last few years, autogenous dentin has been used in bone regeneration procedures, having promising results. Clinical case: a clinical case of a 20-year-old woman is presented, with no interesting medical record, who went to dental clinic for removal of an inverse maxillary bicuspid retained. After maxillary bicuspid and lower third molar extractions, autogenous dentin was obtained from both teeth, to perform a guided bone regeneration of the bicuspid defect. A week and 4-month check-up were carried out. Conclusion: autogenous dentin has shown to be a biocompatible material, adequate for guided bone regeneration procedures, after extraction of impacted teeth, as an alternative to other biomaterials. (AU)

Utilización de dentina autóloga como material de regeneración. Rehabilitación de un paciente mediante tratamiento quirúrgico y prostodóncico con flujo digital / Utilization of autologous dentin as regeneration material. A patients’ rehabilitation by surgical and prosthodontic treatment with digital workflow

Introducción: Existen numerosos procedimientos para conseguir un lecho óseo adecuado para colocar implantes tras la pérdida de dientes naturales. En los últimos años se han propuesto técnicas para la preservación del lecho tras la extracción dental. Los injertos de dentina autóloga ofrecen un sustrato conveniente con propiedades osteoinductivas y osteogénicas óptimas para la regeneración alveolar. Objetivo: Se presenta un caso clínico de un paciente rehabilitado mediante un tratamiento quirúrgico y prostodóntico, y una actualización de la bibliografía en relación con los injertos de dentina autóloga. Caso clínico: Varón de 64 años sin antecedentes médicos ni hábitos patológicos, que presenta desgastes severos, inestabilidad oclusal y problemas estéticos. Se realiza una rehabilitación integral del paciente combinando una técnica quirúrgica de preservación alveolar con injerto de dentina autóloga, tras la cual se procede a la colocación de implantes, con un tratamiento protésico de coronas de zirconio, incrustaciones de disilicato de litio y reconstrucciones de composite. El tratamiento protésico se realiza en dos fases, pasando por una fase de provisionalización previa a la colocación de las restauraciones definitivas, empleando el flujo digital. A los 6 meses el paciente se encuentra satisfecho y con una función y estética óptima. Conclusiones: El injerto de dentina autóloga parece una alternativa eficaz y predecible como material de regeneración alveolar. Combinando esta técnica de preservación con una planificación digital, se puede maximizar el resultado del tratamiento rehabilitador, consiguiendo una mayor satisfacción del paciente. (AU)

Introduction: There are multiple procedures to achieve an adequate bone site for implant placement after teeth loss. In the last years, numerous techniques have been proposed for alveolar preservation. Dentin autologous grafts offer a convenient substrate with osteoinductive and osteogenic properties, which are optimum for alveolar regeneration. Objective: In this article, a clinical case of a patient rehabilitated by surgical and prosthodontic treatment, and a review of the literature regarding autologous dentin grafts is presented. Case report: 64 years old male, with no medical records or parafunctional habits, presents severe wear, occlusal instability and aesthetic problems. An integral rehabilitation is performed combining a surgical preservation technique with autologous dentin graft, after which the placement of the implants takes place, and a prosthodontic treatment with zirconium crowns, lithium disilicate inlays and composite restorations. The prosthodontic treatment is accomplished in two phases, going through a provisionalization phase previous to the placement of the definitive restorations, and digital workflow is used. 6 months later, the patient is satisfied, and function and aesthetic are optimum. Conclusions: Dentin autologous graft offers a predictable and effective alternative as a material for alveolar regeneration. Combining this preservation technique, with a good digital planification, results can be maximized and satisfaction for the patient can be increased. (AU)

Potential of Treated Dentin Matrix Xenograft for Dentin-Pulp Tissue Engineering.

INTRODUCTION: This study aims to develop and characterize the regenerative potential of an atelopeptidized treated dentin matrix xenograft using in vitro and in vivo models. METHODS: Freshly extracted bovine dentin was pulverized into 250- to 500-µm particles and demineralized with 17% EDTA for 1, 7, and 13 days. The samples were atelopeptidized with pepsin. The degree of demineralization and the effect of atelopeptidization were assessed using field emission scanning electron microscopy combined with energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy, respectively. The expression of dentin matrix acidic phosphoprotein 1, dentin sialophosphoprotein, and osteopontin was evaluated in dental pulp stem cells using quantitative real-time polymerase chain reaction. The samples were then implanted intramuscularly in rats for 30 days, and the inflammatory cells were quantified histologically. RESULTS: Field emission scanning electron microscopy combined with energy-dispersive X-ray spectroscopy revealed an exposed tubular structure of dentin after 1 and 7 days of demineralization. Fourier transform infrared spectroscopy confirmed the absence of amide peaks at 1260 to 1640/cm after atelopeptidization. The dental pulp stem cell expression of dentin matrix acidic phosphoprotein 1 and dentin sialophosphoprotein increased in all compared with the untreated control group (P < .05). The maximum expression rates were observed for the 1-day demineralized and atelopeptidized group. The 1-day demineralized group elicited the highest inflammatory response compared with the 7- or 13-day demineralized groups (P < .001). Atelopeptidization significantly decreased the inflammatory response only in the 1-day demineralized dentin group (P < .05). CONCLUSIONS: Atelopeptidization of 1-day demineralized dentin xenograft preserved the collagen structure, minimized the immune reaction, and provided sufficient regenerative potential.

Use of autologous tooth-derived graft material in the post-extraction dental socket. Pilot study

Background: The objectives of the present pilot study are to compare via CBCT the alveolar contraction suffered both vertically and horizontally between the control group and the group using autologous dental material (ADM), as well as to study the densitometric differences between both post-extraction sockets. Material and Methods: A split-mouth study was performed in n = 9 patients who required two extraction of single-rooted teeth deemed suitable for deferred rehabilitation with osseointegrated implants. Two groups were formed - a control group, in which the post-extraction socket was not filled, and an ADM group, in which the alveolar defect was filled with freshly processed autogenous dental material. Both dimensional and densitometric analyses of the alveoli were performed in both groups immediately after surgery (baseline), as well as 8 weeks and 16 weeks later. Results: The mean height of alveolar bone loss was: VL (Control 1.77 mm, loss of 16.87% of initial alveolar height; ADM 0.42 mm, loss of 4.2% of initial alveolar height), HL-BCB (Control 2.22 mm, ADM 0.16 mm, p= 0.067 at 16 weeks). The mean bone loss of the vestibular width (VL-BCB) was much higher in the control group (1.91 mm at 1 mm, 1.3 mm at 3 mm, and 0.89 mm at 5 mm) than in the ADM group (0.46 mm at 1 mm, 0.21 mm at 3 mm, 0.01 at 5 mm, p=0.098 at 16 weeks). At 16 weeks, densitometric analysis of the coronal alveolar area revealed a bone density of 564.35 ± 288.73 HU in the control group and 922.68 ± 250.82 HU in the ADM group (p=0.045 ). Conclusions: In light of these preliminary results, autologous dentine may be considered a promising material for use in socket preservation techniques

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Use of autologous tooth-derived graft material in the post-extraction dental socket. Pilot study.

BACKGROUND: The objectives of the present pilot study are to compare via CBCT the alveolar contraction suffered both vertically and horizontally between the control group and the group using autologous dental material (ADM), as well as to study the densitometric differences between both post-extraction sockets. MATERIAL AND METHODS: A split-mouth study was performed in n = 9 patients who required two extraction of single-rooted teeth deemed suitable for deferred rehabilitation with osseointegrated implants. Two groups were formed - a control group, in which the post-extraction socket was not filled, and an ADM group, in which the alveolar defect was filled with freshly processed autogenous dental material. Both dimensional and densitometric analyses of the alveoli were performed in both groups immediately after surgery (baseline), as well as 8 weeks and 16 weeks later. RESULTS: The mean height of alveolar bone loss was: VL (Control 1.77 mm, loss of 16.87% of initial alveolar height; ADM 0.42 mm, loss of 4.2% of initial alveolar height), HL-BCB (Control 2.22 mm, ADM 0.16 mm, p= 0.067 at 16 weeks). The mean bone loss of the vestibular width (VL-BCB) was much higher in the control group (1.91 mm at 1 mm, 1.3 mm at 3 mm, and 0.89 mm at 5 mm) than in the ADM group (0.46 mm at 1 mm, 0.21 mm at 3 mm, 0.01 at 5 mm, p=0.098 at 16 weeks). At 16 weeks, densitometric analysis of the coronal alveolar area revealed a bone density of 564.35 ± 288.73 HU in the control group and 922.68 ± 250.82 HU in the ADM group (p=0.045 ). CONCLUSIONS: In light of these preliminary results, autologous dentine may be considered a promising material for use in socket preservation techniques.

Clinical application of autogenous demineralized dentin matrix loaded with recombinant human bone morphogenetic-2 for socket preservation: A case series.

BACKGROUND: Demineralized dentin matrix (DDM) has potential application as a carrier for recombinant human bone morphogenetic protein-2 (rhBMP-2) in bone regeneration. PURPOSE: To evaluate the efficacy of DDM loaded with rhBMP-2 for socket preservation. MATERIALS AND METHODS: DDM loaded with rhBMP-2 (DDM/rhBMP-2) was applied to 10 experimental sites and DDM alone to 6 control sites. The changes in height and width of the extraction socket after preservation were measured by cone beam computed tomography. Trephine cores were harvested for histomorphometric evaluation before placement of the implant. RESULTS: The reductions in height and width of the socket were more significant in the group treated with DDM than in the group treated with DDM/rhBMP-2. The amount of new bone formation was 34.39% with DDM/rhBMP-2 and 29.75% with DDM; the respective amounts of residual dentin were 8.35% and 16.15%. Although the differences were not statistically significant, the dimensional changes, amount of bone formation, and replacement of DDM in DDM/rhBMP-2 with bone were superior to those of DDM alone. CONCLUSIONS: Within the limitations of this study, we suggest that DDM may be a potential carrier for rhBMP-2 and that it may be possible to reduce the rhBMP-2 concentration to 0.2 mg/mL.

TREATMENT OF UNICAMERAL BONE CYSTS IN CHILDREN: A COMPARATIVE STUDY.

Unicameral bone cysts (UBC) are benign bone tumor-like lesions. Mostly they are located in the metaphyseal-diaphyseal region of long bones in children and adolescents. The etiology of UBC is still unclear. There is no consensus about the protocol of UBC treatment. The aim of this study was to evaluate the effectiveness of three different techniques for the treatment of UBC. This study included 129 pediatric patients with UBC treated at University Children's Hospital in Belgrade during the 8-year period. The mean follow up was 7.14 years. The following parameters were observed: gender, age, site, length of cyst, cyst index, cortical thickness, presentation of pathologic fracture, healing of cyst, treatment complications and length of hospitalization. These parameters were correlated to three treatment modalities, i.e. intracystic methylprednisolone acetate injection (group 1), curettage with bone grafting (group 2) and osteoinductive procedure using demineralized bone matrix (group 3). We found statistically significant differences in healing of the cysts and length of hospital treatment between groups 1 and 2, and between groups 2 and 3. In conclusion, complete healing of UBC can be achieved only using open surgery procedure. Intracystic methylprednisolone acetate instillation can be considered a good option for initial treatment of UBC.

Three-dimensional ultrastructural analysis of the interface between an implanted demineralised dentin matrix and the surrounding newly formed bone.

Previous investigators have reported that transplanted demineralised dentin matrix (DDM) influences bone formation in vivo. However, the specific mechanism of how dentinal tubules contribute to bone formation has not been determined with regard to DDM transplantation therapy. In this study, we ultrastructurally investigated how DDM contacted the surrounding newly formed bone using a scanning electron microscopy (SEM) three-dimensional reconstruction method that is based on focused ion beam slicing and SEM (FIB/SEM). A pulverised and processed DDM derived from human teeth was implanted into rat calvarial bone defects, and a series of X-ray computed tomographic images were obtained over 12 weeks. Implants with surrounding new bone were removed and histologically examined using FIB/SEM. After obtaining objective block-face images, the target boundary face was reconstructed three-dimensionally. The osteocytes of the new bone tissue surrounding the DDM formed a network connected by their cellular processes and formed bone tissue. It is also interesting that the cellular processes of the osteocytes extended into the dentinal tubules, and that bone tissue with canaliculi had formed and filled the DDM surface.

Bone marrow mesenchymal stem cells combine with Treated dentin matrix to build biological root.

Treated dentin matrix (TDM) as a kind of scaffolding material has been proved odontogenic induction ability on dental-derived stem cells. Given the limited resources of dental stem cells, it is necessary to seek new seed cell which easily obtained. Jaw bone marrow mesenchymal stem cell (JBMMSC) as non-dental-derived stem cell relates to the development of teeth and jaws which suggest us JBMMSCs could act as a new seed cell for tooth tissue engineering. To assess the odontogenic and osteogenic potential of JBMMSCs, cells were induced by TDM extraction in vitro and combined with TDM in vivo. Results were analyzed by PCR, Western Blotting and histology. PCR and Western Blotting showed odontogenic and osteogenic makers were significantly enhanced in varying degrees after induced by TDM extraction in vitro. In vivo, JBMMSCs expressed both odontogenic and osteogenic-related protein, and the latter showed stronger positive expression. Furthermore, histological examination of the harvested grafts was observed the formation of bone-like tissue. Therefore, osteogenic differentiation ability of JBMMSCs were enhanced significantly after being inducted by TDM which illustrates that non-odontogenic derived stem cells are still promising seed cells in tooth root tissue engineering.

Human tooth-derived biomaterial as a graft substitute for hard tissue regeneration.

AIM: The present study was conducted to evaluate the efficacy of human dentine grafts for new bone augmentation. MATERIALS & METHODS: Dentine grafts (demineralized dentine matrix [DDM] and mineralized dentine matrix [MDM]) were prepared and implanted in rats. Tetracycline was administered twice. Paraffin and resin sections were prepared from the harvested grafts and stained respectively with hematoxylin and eosin (in addition to tartrate acid phosphatase for osteoclasts) and Villanueva. The new bone formation (bone thickness, mineral apposition rate and the bone formation rate) was analyzed in tetracycline-labeled resin sections. RESULTS & CONCLUSION: DDM grafts implanted in bone were better able to augment the bone compared to MDM grafts. However, both MDM and DDM failed to induce new bone in ectopic site, they could be considered as alternative autograft substitutes after protocol optimization.

Evaluation of perforated demineralized dentin scaffold on bone regeneration in critical-size sheep iliac defects.

OBJECTIVES: Regenerating critical-size bone injury is a major problem that continues to inspire the design of new graft materials. Therefore, tissue engineering has become a novel approach for targeting bone regeneration applications. Human teeth are a rich source of stem cells, matrix, trace metal ions, and growth factors. A vital tooth-derived demineralized dentin matrix is acid-insoluble and composed of cross-linked collagen with growth factors. In this study, we recycled human non-functional tooth into a unique geometric dentin scaffold, entitled perforated root-demineralized dentin matrix (PR-DDM). The aim of this study was to evaluate the feasibility of PR-DDM as the scaffold for regenerating bone in critical-size iliac defects. MATERIAL AND METHODS: Artificial macro-pores (1 mm in diameter) were added to human vital wisdom tooth after removing the enamel and pulp portions. The modified tooth was demineralized in 0.34 N HNO3 for 30 min and is referred to as PR-DDM scaffold. Critical-size defect (10 mm × 15 mm × 9 mm Ø) was created in the iliac crest of six adult sheep. The in vivo bone regeneration by the scaffold was evaluated by micro-CT, 3D micro-CT, and histological examination at 2 and 4 months post-implantation. RESULTS: PR-DDM exhibited better bone ingrowth, especially in the artificial macro-pores. The results of micro-CT and 3D micro-CT revealed good union between scaffold and native bone. New bone formation was observed in almost all portions of PR-DDM. Higher bone volume inside the scaffold was detected at 4 months compared with 2 months. New bone ingrowth was ankylosed with PR-DDM, and both osteoinduction and osteoconduction capability of PR-DDM were confirmed histologically. The ratio of new bone formation was higher at 4 months compared with 2 months by histomorphometric analysis. CONCLUSIONS: Altogether, these results demonstrated that the human tooth-derived graft material with a unique geometric structure, PR-DDM, contributed to active bone ingrowth in critical-size bone defects. This novel scaffold may have great utility in the near-future clinical application.

Autogenous demineralized dentin matrix from extracted tooth for the augmentation of alveolar bone defect: a prospective randomized clinical trial in comparison with anorganic bovine bone.

OBJECTIVES: The aim of this study was to prospectively evaluate the clinical efficacy and histological outcome of the autogenous tooth graft material (AutoBT) compared to that of anorganic bovine bone (Bio-Oss® , Geistlich, Switzerland) in post-extraction alveolar bone augmentation. PATIENTS AND METHODS: A total of 33 graft sites in 24 patients were included in this study. AutoBT was used in 21 sites of 15 patients and Bio-Oss® was used in 12 sites of 9 patients for alveolar bone augmentation 2-4 weeks after dental extraction. Vertical dimension of grafted bone was measured both at the time of graft placement and at implant fixture placement after 6 months. Trephine cores were harvested for the histomorphometric evaluations during implant placement when feasible. The primary stability of implant fixture was also measured. RESULTS: Infection of graft material or graft bed was not observed and graft sites healed without any notable complications in both groups. The vertical dimensions of alveolar bone increased by 5.38 ± 2.65 mm in AutoBT group and 6.56 ± 3.54 mm in Bio-Oss® group at 6 months post-extraction. Histomorphometrically, new bone formation of AutoBT-grafted site was 31.24 ± 13.87% while that of Bio-Oss® was 35.00 ± 19.33%. The implant stability quotient (ISQ) of implants placed in AutoBT-grafted sites measured 72.80 ± 10.81 while those placed in Bio-Oss® -grafted sites measured 70.0 ± 12.86. There were no statistically significant differences between measurements of the two groups. CONCLUSION: Autogenous demineralized dentin matrix from extracted tooth grafted to extraction sockets for the augmentation of vertical dimension was as effective as augmentation using anorganic bovine bone. Both groups showed favorable wound healing, similar amount of implant stability, and histologically confirmed new bone formation. Thus, the results of this study suggest that autogenous tooth graft material is a viable option for alveolar bone augmentation following dental extraction.

Liquid nitrogen-treated autogenous dentin as bone substitute: an experimental study in a rabbit model.

PURPOSE: Different forms of dentin, including untreated, undemineralized, demineralized, boiled, or mixed with other materials, have been evaluated for efficacy as bone substitutes. However, the effects of application of liquid nitrogen-treated dentin for bone grafting remain unknown. The objective of this study was to chronologically evaluate bone healing following grafting with liquid nitrogen-treated dentin in a rabbit model. MATERIALS AND METHODS: Autogenous dentin treated with liquid nitrogen at -196°C for 20 minutes was used. In 16 New Zealand White rabbits, a bone defect (5 mm in diameter) was created in each femur and randomly grafted with either autogenous dentin (experimental group) or autogenous bone grafts (positive control). In another four rabbits (negative control), a similar defect in each femur was left empty. The rabbits were sacrificed at 2, 4, 8, and 12 weeks. Explants of grafted sites were harvested for histologic and histomorphometric analysis. RESULTS: At 2 and 4 weeks in both the experimental and positive control groups, accelerated formation of new bone was observed, which was undergoing remodeling at 8 and 12 weeks. The mean new bone score was higher in the experimental than in the negative control groups, but this was not statistically significant. CONCLUSION: The present results demonstrated that liquid nitrogen-treated autogenous dentin has both osteoconductive and osteoinductive properties and therefore has potential as a bone substitute.

An approach to biomimetics: the natural CAD/CAM restoration: a clinical report.

Those in the dental field have always pursued the perfect dental material for the treatment of compromised teeth. Gold, amalgam, composite resin, glass ionomer, and porcelain have been used. Tooth-like restorative materials (composite resin and porcelain) combined with an effective hard tissue bond have met the growing demand for esthetic or metal-free restorations in the past 15 to 20 years. However, none of those materials can fully mimic the unique properties of dentin (compliance and crack-stopping behavior) and enamel (wear resistance, function). The aim of this article is to report the restoration of an extensively damaged tooth with a natural restoration obtained by milling an extracted third molar tooth with a computer-aided design and computer-aided manufacturing (CAD/CAM) system. The main benefit of this novel technique is the replacement of lost tissues by actual enamel and dentin, with the potential to recover mechanical, esthetic, and biologic properties. The indication for extracting third molars and premolars because of impaction or for orthodontic reasons makes these posterior teeth readily available. The innovation of the method presented here is the optimal use of the extracted tooth substrate thanks to its positioning technique in the CAD/CAM milling chamber.

Host tissue reactions of non-demineralized autogenic and xenogenic dentin blocks implanted in a non-osteogenic environment. An experimental study in rabbits.

Dentoalveolar ankylosis with osseous replacement is often seen after replantation of avulsed teeth, and this process may be used for preservation of alveolar crests after trauma. Its exact mechanisms with regard to osteoinductive properties are not yet fully understood and need to be systematically investigated. Dentin can possibly act as a slow-releasing carrier of bone morphogenic proteins (BMP), and this property of dentin has been proposed to be used as an alternative or supplement to bone grafting in the maxillofacial region. We aimed to initially asses host tissue reactions to dentin by implanting dentin blocks of autogenic and xenogenic human origin in rabbit connective tissue of the abdominal wall and femoral muscle. Animals were sacrificed after a period of 3 months, and histological processing, sectioning and examinations were carried out. Bone formation, cell counts and thickness of capsule surrounding the grafts were evaluated. Only minor signs of heterotopic bone formation were seen. There were no significant differences between autografts and xenografts or grafts implanted in connective tissue or muscle with regards to tissue reactions except for a significant difference (P = 0.018) in findings of more local inflammatory cells in relation to grafts placed in connective tissue in the autograft group. We conclude that during the time frame of this study, non-demineralized dentin, whether autogenous or xenogenic did not have the potential to induce bone formation when implanted in non-osteogenic areas such as the abdominal wall and abdominal muscle of rabbits.