Autogenous dentin graft versus alloplastic graft combined with socket shield for pre-implant socket preservation: a split-mouth randomized clinical trial.

After tooth extraction, alveolar bone resorption and labial bone plate thinning occur due to the lack of periodontal ligaments. The socket shield method was developed to preserve the alveolar ridge. A split-mouth study was performed in which eight patients were treated using alloplast with socket shield on one side (alloplast group, control) and autogenous dentin graft with socket shield on the contralateral side (dentin group, test). After 3 months, a trephine bone core was collected from all sites and evaluated by histological, histomorphometric, and radiographic analysis. Thin bony trabeculae were formed surrounding the residual alloplast, while thicker trabeculae of bone formed and fused to the autogenous dentin. The percentage of newly formed bone was significantly higher in the dentin group when compared to the alloplast group (P = 0.020). Radiographically, there was no significant difference in the mean percentage increase in bone density from preoperative to post-grafting between the two groups. Moreover, when comparing the change in labial bone level from preoperative to 3 months post-grafting between the two groups, there was no significant difference. The autogenous dentin graft combined with socket shield could be a promising technique for socket preservation.

Transcriptome profile of highly osteoblastic/cementoblastic periodontal ligament cell clones

Abstract Heterogeneous cell populations of osteo/cementoblastic (O/C) or fibroblastic phenotypes constitute the periodontal dental ligament (PDL). A better understanding of these PDL cell subpopulations is essential to propose regenerative approaches based on a sound biological rationale. Objective Our study aimed to clarify the differential transcriptome profile of PDL cells poised to differentiate into the O/C cell lineage. Methodology To characterize periodontal-derived cells with distinct differentiation capacities, single-cell-derived clones were isolated from adult human PDL progenitor cells and their potential to differentiate into osteo/cementoblastic (O/C) phenotype (C-O clones) or fibroblastic phenotype (C-F clones) was assessed in vitro. The transcriptome profile of the clonal cell lines in standard medium cultivation was evaluated using next-generation sequencing technology (RNA-seq). Over 230 differentially expressed genes (DEG) were identified, in which C-O clones showed a higher number of upregulated genes (193) and 42 downregulated genes. Results The upregulated genes were associated with the Cadherin and Wnt signaling pathways as well as annotated biological processes, including "anatomical structure development" and "cell adhesion." Both transcriptome and RT-qPCR showed up-regulation of WNT2, WNT16, and WIF1 in C-O clones. Conclusions This comprehensive transcriptomic assessment of human PDL progenitor cells revealed that expression of transcripts related to the biological process "anatomical structure development," Cadherin signaling, and Wnt signaling can identify PDL cells with a higher potential to commit to the O/C phenotype. A better understanding of these pathways and their function in O/C differentiation will help to improve protocols for periodontal regenerative therapies.

The Fate of Transplanted Periodontal Ligament Stem Cells in Surgically Created Periodontal Defects in Rats.

Periodontal disease is chronic inflammation that leads to the destruction of tooth-supporting periodontal tissues. We devised a novel method ("cell transfer technology") to transfer cells onto a scaffold surface and reported the potential of the technique for regenerative medicine. The aim of this study is to examine the efficacy of this technique in periodontal regeneration and the fate of transplanted cells. Human periodontal ligament stem cells (PDLSCs) were transferred to decellularized amniotic membrane and transplanted into periodontal defects in rats. Regeneration of tissues was examined by microcomputed tomography and histological observation. The fate of transplanted PDLSCs was traced using PKH26 and human Alu sequence detection by PCR. Imaging showed more bone in PDLSC-transplanted defects than those in control (amnion only). Histological examination confirmed the enhanced periodontal tissue formation in PDLSC defects. New formation of cementum, periodontal ligament, and bone were prominently observed in PDLSC defects. PKH26-labeled PDLSCs were found at limited areas in regenerated periodontal tissues. Human Alu sequence detection revealed that the level of Alu sequence was not increased, but rather decreased. This study describes a novel stem cell transplantation strategy for periodontal disease using the cell transfer technology and offers new insight for cell-based periodontal regeneration.

Litsea japonica Leaf Extract Suppresses Proinflammatory Cytokine Production in Periodontal Ligament Fibroblasts Stimulated with Oral Pathogenic Bacteria or Interleukin-1ß.

Periodontal disease, a chronic disease caused by bacterial infection, eventually progresses to severe inflammation and bone loss. Regulating excessive inflammation of inflamed periodontal tissues is critical in treating periodontal diseases. The periodontal ligament (PDL) is primarily a connective tissue attachment between the root and alveolar bone. PDL fibroblasts (PDLFs) produce pro-inflammatory cytokines in response to bacterial infection, which could further adversely affect the tissue and cause bone loss. In this study, we determined the ability of Litsea japonica leaf extract (LJLE) to inhibit pro-inflammatory cytokine production in PDLFs in response to various stimulants. First, we found that LJLE treatment reduced lipopolysaccharide (LPS)-induced pro-inflammatory cytokine (interleukin-6 and interleukin-8) mRNA and protein expression in PDLFs without cytotoxicity. Next, we observed the anti-inflammatory effect of LJLE in PDLFs after infection with various oral bacteria, including Fusobacterium nucleatum, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. These anti-inflammatory effects of LJLE were dose-dependent, and the extract was effective following both pretreatment and posttreatment. Moreover, we found that LJLE suppressed the effect of interleukin-1 beta-induced pro-inflammatory cytokine production in PDLFs. Taken together, these results indicate that LJLE has anti-inflammatory activity that could be exploited to prevent and treat human periodontitis by controlling inflammation.

Histological evaluation of periodontal ligament in human after orthodontic treatment with piezosurgery and monolateral tooth dislocation and ligament distraction technique: a first morphologic and histologic evaluation.

Traditional orthodontic tooth movement is based on the concept that application of a protracted force causes alveolar bone remodelling and adaptive changes in periodontal and dental tissues. Thus, if orthodontic tooth movement is described as a biological bone reaction to orthodontic forces mediated by the periodontal ligament (PDL), this event involves a series of sophisticated signal transduction processes that allows the PDL compression with specific histologic and biomolecular modifications. However, the preservation of the integrity of the PDL is generally difficult to achieve when it is associated with a long duration of orthodontic treatment. A total of 20 Caucasian patients with different dental-skeletal were treated using the Monocortical Tooth Dislocation and Ligament Distraction (MTDLD) technique with Piezosurgery associated with morphologic and histological evaluation of the PDL. The histological results obtained, confirm a good clinical outcome with an improvement of the speed on orthodontic treatment without any signs of tissue injury of PDL fiber without areas of hyalinization. The data suggests that MTDLD with Piezosurgery seems to be a valid alternative to the traditional orthodontic movement in adult patients preserving the anatomy and the integrity of PDL.

Mineralization Induction of Gingival Fibroblasts and Construction of a Sandwich Tissue-Engineered Complex for Repairing Periodontal Defects.

BACKGROUND The ideal healing technique for periodontal tissue defects would involve the functional regeneration of the alveolar bone, cementum, and periodontal ligament, with new periodontal attachment formation. In this study, gingival fibroblasts were induced and a "sandwich" tissue-engineered complex (a tissue-engineered periodontal membrane between 2 tissue-engineered mineralized membranes) was constructed to repair periodontal defects. We evaluated the effects of gingival fibroblasts used as seed cells on the repair of periodontal defects and periodontal regeneration. MATERIAL AND METHODS Primitively cultured gingival fibroblasts were seeded bilaterally on Bio-Gide collagen membrane (a tissue-engineered periodontal membrane) or unilaterally on small intestinal submucosa segments, and their mineralization was induced. A tissue-engineered sandwich was constructed, comprising the tissue-engineered periodontal membrane flanked by 2 mineralized membranes. Periodontal defects in premolar regions of Beagles were repaired using the tissue-engineered sandwich or periodontal membranes. Periodontal reconstruction was compared to normal and trauma controls 10 or 20 days postoperatively. RESULTS Periodontal defects were completely repaired by the sandwich tissue-engineered complex, with intact new alveolar bone and cementum, and a new periodontal ligament, 10 days postoperatively. CONCLUSIONS The sandwich tissue-engineered complex can achieve ideal periodontal reconstruction rapidly.

Evaluating the oxysterol combination of 22(S)-hydroxycholesterol and 20(S)-hydroxycholesterol in periodontal regeneration using periodontal ligament stem cells and alveolar bone healing models.

BACKGROUND: Oxysterols, oxygenated by-products of cholesterol biosynthesis, play roles in various physiological and pathological systems. However, the effects of oxysterols on periodontal regeneration are unknown. This study investigated the effects of the specific oxysterol combination of 22(S)-hydroxycholesterol and 20(S)-hydroxycholesterol (SS) on the regeneration of periodontal tissues using in-vitro periodontal ligament stem cells (PDLSCs) and in-vivo models of alveolar bone defect. METHODS: To evaluate the effects of the combined oxysterols on PDLSC biology, we studied the SS-induced osteogenic differentiation of PDLSCs by assessing alkaline phosphatase activity, intracellular calcium levels [Ca2+]i, matrix mineralization, and osteogenic marker mRNA expression and protein levels. To verify the effect of oxysterols on alveolar bone regeneration, we employed tooth extraction bone defect models. RESULTS: Oxysterols increased the osteogenic activity of PDLSCs compared with the control group. The expression of liver X receptor (LXR) α and ß, the nuclear receptors for oxysterols, and their target gene, ATP-binding cassette transporter A1 (ABCA1), increased significantly during osteogenesis. Oxysterols also increased protein levels of the hedgehog (Hh) receptor Smo and the transcription factor Gli1. We further confirmed the reciprocal reaction between the LXRs and Hh signaling. Transfection of both LXRα and LXRß siRNAs decreased Smo and Gli1 protein levels. In contrast, the inhibition of Hh signaling attenuated the LXRα and LXRß protein levels. Subsequently, SS-induced osteogenic activity of PDLSCs was suppressed by the inhibition of LXRs or Hh signaling. The application of SS also enhanced bone formation in the defect sites of in-vivo models, showing equivalent efficacy to recombinant human bone morphogenetic protein-2. CONCLUSIONS: These findings suggest that a specific combination of oxysterols promoted periodontal regeneration by regulating PDLSC activity and alveolar bone regeneration.

Healing of two-wall intra-bony defects treated with a novel EMD-liquid-A pre-clinical study in monkeys.

AIM: To investigate the effect of a novel enamel matrix derivative formulation (EMD-liquid or Osteogain) combined with an absorbable collagen sponge (ACS) on periodontal wound healing in intra-bony defects in monkeys. MATERIALS AND METHODS: Chronic two-wall intra-bony defects were created at the distal aspect of eight teeth in three monkeys (Macaca fascicularis). The 24 defects were randomly assigned to one of the following treatments: (i) open flap debridement (OFD) + ACS alone, (ii) OFD + Emdogain + ACS (Emdogain/ACS), (iii) OFD + Osteogain + ACS (Osteogain/ACS) or (iv) OFD alone. At 4 months, the animals were euthanized for histologic evaluation. RESULTS: Osteogain/ACS resulted in more consistent formation of cementum, periodontal ligament and bone with limited epithelial proliferation compared to OFD alone, Emdogain/ACS and OFD + ACS. Among the four treatment groups, the Osteogain/ACS group demonstrated the highest amount of regenerated tissues. However, complete periodontal regeneration was not observed in any of the defects in the four groups. CONCLUSIONS: The present findings indicate that in two-wall intra-bony defects, reconstructive surgery with Osteogain/ACS appears to be a promising novel approach for facilitating periodontal wound healing/regeneration, thus warranting further clinical testing.

Contribution of the PDL to Osteotomy Repair and Implant Osseointegration.

Our objective was to clarify the fate of the periodontal ligament (PDL) retained in the socket after tooth extraction, then determine if this tissue contributed to the osseointegration of "immediate" implants placed in these fresh extraction sockets. Mice underwent maxillary first molar extraction, the residual PDL was removed by an osteotomy, and titanium implants were placed. The osteotomy was created in such a way that the palatal surface was devoid of PDL remnants while the buccal, mesial, and distal surfaces retained PDL fibers. At multiple time points after surgery, tissues were analyzed using a battery of molecular, cellular, and histomorphometrical assays. We found that PDL remnants mineralized and directly contributed to new bone formation in the extraction site. Compared with regions of an extraction site where the PDL was removed by osteotomy, regions that retained PDL fibers had produced significantly more new bone. Around immediate implants, the retained PDL remnants directly contributed to new bone formation and osseointegration. Thus, we conclude that PDL remnants are inherently osteogenic, and if the tissue is healthy, it is reasonable to conclude that curetting out an extraction socket prior to immediate implant placement should be avoided. This recommendation aligns with contemporary trends toward minimally invasive surgical manipulations of the extraction socket prior to immediate implant placement.

The use of platelet-rich fibrin combined with periodontal ligament and jaw bone mesenchymal stem cell sheets for periodontal tissue engineering.

Periodontal regeneration involves the restoration of at least three unique tissues: cementum, periodontal ligament tissue (PDL) and alveolar bone tissue. Here, we first isolated human PDL stem cells (PDLSCs) and jaw bone mesenchymal stem cells (JBMSCs). These cells were then induced to form cell sheets using an ascorbic acid-rich approach, and the cell sheet properties, including morphology, thickness and gene expression profile, were compared. Platelet-rich fibrin (PRF) derived from human venous blood was then fabricated into bioabsorbable fibrin scaffolds containing various growth factors. Finally, the in vivo potential of a cell-material construct based on PDLSC sheets, PRF scaffolds and JBMSC sheets to form periodontal tissue was assessed in a nude mouse model. In this model, PDLSC sheet/PRF/JBMSC sheet composites were placed in a simulated periodontal space comprising human treated dentin matrix (TDM) and hydroxyapatite (HA)/tricalcium phosphate (TCP) frameworks. Eight weeks after implantation, the PDLSC sheets tended to develop into PDL-like tissues, while the JBMSC sheets tended to produce predominantly bone-like tissues. In addition, the PDLSC sheet/PRF/JBMSC sheet composites generated periodontal tissue-like structures containing PDL- and bone-like tissues. Further improvements in this cell transplantation design may have the potential to provide an effective approach for future periodontal tissue regeneration.

Osseous resective surgery with and without fibre retention technique in the treatment of shallow intrabony defects: a split-mouth randomized clinical trial.

AIM: The aim of this split-mouth clinical trial was to compare the effectiveness of Apically Positioned Flap with Fibre Retention Osseous Resective Surgery (FibReORS) or Osseous Resective Surgery (ORS) in the treatment of periodontal pockets associated with intrabony defects ≤ 3 mm at posterior natural teeth. MATERIALS AND METHODS: Twenty-six posterior sextants requiring osseous resective surgery were selected in 13 chronic periodontitis patients: 13 sextants were randomly assigned to ORS and 13 to FibReORS. Clinical evaluation of probing depth (PD), gingival recession and clinical attachment level was performed at baseline, 6 and 12 months postoperatively. Periapical radiographs were taken prior and after surgical treatment, at 6- and 12-month follow-up. RESULTS: Ostectomy amounted to 1.0 ± 0.3 mm in the ORS group and to 0.4 ± 0.2 mm in the FibReORS group. At 12-month examination PD changes did not significantly differ between the experimental groups. ORS group showed significantly (p < 0.001) greater clinical attachment loss (2.2 ± 1.0 mm versus 1.0 ± 0.6 mm), radiographic bone resorption (0.43 ± 0.08 mm versus 0.13 ± 0.09 mm) and post-operative patient discomfort compared to FibReORS. CONCLUSION: FibReORS resulted in similar PD reduction, but less ostectomy, clinical attachment loss and patient morbidity compared to ORS.

Análise histométrica do processo de reparo do reimplante dentário submetido à terapia com laser de baixa intensidade: estudo em ratos / Histommetric analyisis of tooth immediate replantation repair process submitted to low level laser therapy: study in rats

Para averiguar a influência da terapia com laser de baixa intensidade (LLLT) no processo de reparo em reimplante dentário, 90 ratos divididos em 3 grupos de 30 animais tiveram o incisivo superior direito extraído. No grupo C o incisivo foi reimplantado sem intervenção adicional. Nos grupos L1 e L2, os dentes foram irradiados com laser diodo antes, no interior do alvéolo, e logo após o reimplante, na parte externa do alvéolo. Essa dose foi repetida as 24, 48 e 72 horas pós-operatórias no grupo L1 e as 48, 96 e 144 horas no grupo L2. Após períodos de 7, 14 e 30 dias, os animais foram sacrificados para análise histológica em hematoxilina e eosina e Picrosirius Red. Observamos valores menores de inflamação no ligamento periodontal no grupo L1 (p<0,05) aos 7 dias. Maior extensão de ligamento periodontal reinserido, nos grupos L1 e L2, aos 7 e 14 dias. Maior extensão de tecido pulpar normal foi encontrada nos grupos L1 e L2 no período de 14 dias. Maior comprometimento pela reabsorção radicular foi observado no grupo C aos 30 dias. Pode-se concluir que a terapia com LLLT influiu positivamente no reparo do ligamento periodontal e tecido pulpar do dente reimplantado.

To investigate the influence of low intensity laser therapy (LLLT) in the repair process of dental reimplantation, 90 mice divided into 3 groups of 30 animals had the right upper incisor extracted. In group C the incisive was reimplanted without further intervention. In the groups L1 and L2, the teeth were irradiated with diode laser before, inside the socket, and after reimplantation, outside of the socket. This dose was repeated 24, 48 and 72 hours after surgery, the group L1 and 48, 96 and 144 hours in the L2 group. After periods of 7, 14 and 30 days, the animals were sacrificed for histological examination with hematoxylin and eosin and Picrosirius Red. We observed smaller values of inflammation in the periodontal ligament in the L1 group (p <0.05) at 7 days. Increased length of periodontal ligament reinserted in the L1 and L2 groups at 7 and 14 days. Greater extent normal pulp tissue was found in the groups L1 and L2 within 14 days. Greater commitment by root resorption was observed in group C at 30 days. It can be concluded that LLLT therapy had a positive influence on the repair of the periodontal ligament and the pulp tissue reimplanted tooth.

Effectiveness of Er:YAG laser-aided fiberotomy and low-level laser therapy in alleviating relapse of rotated incisors.

INTRODUCTION: In this study, we compared the effectiveness of laser-aided circumferential supracrestal fiberotomy (CSF) and low-level laser therapy (LLLT) with conventional CSF in reducing relapse of corrected rotations. METHODS: The study included 24 patients who were at the finishing stage of orthodontic treatment and had at least 1 maxillary incisor with 30° to 70° of rotation before starting therapy. The subjects were divided into 4 groups by treatment: conventional CSF, Er:YAG laser-aided CSF, LLLT, and control. After alginate impressions were taken, the archwire was sectioned from the experimental incisors, and they were allowed to relapse. The second impression was taken 1 month later, and the degree and percentage of relapse were calculated in photographs taken from the dental models. Gingival recession, pocket depth, and pain were also measured in the CSF groups. RESULTS: The mean percentages of relapse were 9.7% in the conventional CSF, 12.7% in the Er:YAG laser-aided CSF, 11.7% in the LLLT, and 27.8% in the control groups. Relapse was significantly greater in the control than the experimental groups (P <0.05), which were not statistically different from each other. The changes in sulcus depth and gingival recession were small and not significantly different among the CSF groups (P >0.05), but pain intensity was greater in subjects who underwent conventional CSF (P = 0.003). CONCLUSIONS: Er:YAG laser-aided CSF proved to be an effective alternative to conventional CSF in reducing rotational relapse. LLLT with excessively high energy density was also as effective as the CSF procedures in alleviating relapse, at least in the short term.

Effects of Activin A on the phenotypic properties of human periodontal ligament cells.

Periodontal ligament (PDL) tissue plays an important role in tooth preservation by structurally maintaining the connection between the tooth root and the bone. The mechanisms involved in the healing and regeneration of damaged PDL tissue, caused by bacterial infection, caries and trauma, have been explored. Accumulating evidence suggests that Activin A, a member of the transforming growth factor-ß (TGF-ß) superfamily and a dimer of inhibinßa, contributes to tissue healing through cell proliferation, migration, and differentiation of various target cells. In bone, Activin A has been shown to exert an inhibitory effect on osteoblast maturation and mineralization. However, there have been no reports examining the expression and function of Activin A in human PDL cells (HPDLCs). Thus, we aimed to investigate the biological effects of Activin A on HPDLCs. Activin A was observed to be localized in HPDLCs and rat PDL tissue. When PDL tissue was surgically damaged, Activin A and IL-1ß expression increased and the two proteins were shown to be co-localized around the lesion. HPDLCs treated with IL-1ß or TNF-α also up-regulated the expression of the gene encoding inhibinßa. Activin A promoted chemotaxis, migration and proliferation of HPDLCs, and caused an increase in fibroblastic differentiation of these cells while down-regulating their osteoblastic differentiation. These osteoblastic inhibitory effects of Activin A, however, were only noted during the early phase of HPDLC osteoblastic differentiation, with later exposures having no effect on differentiation. Collectively, our results suggest that Activin A could be used as a therapeutic agent for healing and regenerating PDL tissue in response to disease, trauma or surgical reconstruction.

Clinical guide to periodontology: reconstructive periodontal treatment.

Regeneration of the lost tissues of the periodontium is an ideal therapeutic goal and has been the subject of much research and ingenious clinical techniques. Reconstructive or regenerative techniques are used either singly or in combination for three main purposes: (1) to regain lost periodontal ligament attachment, (2) to provide a wider zone of attached gingiva, and (3) to cover previously exposed root surfaces.

Finite element analysis of rapid canine retraction through reducing resistance and distraction

Objective: The aims of this study were to compare different surgical approaches to rapid canine retraction by designing and selecting the most effective method of reducing resistance by a three-dimensional finite element analysis. Material and Methods: Three-dimensional finite element models of different approaches to rapid canine retraction by reducing resistance and distraction were established, including maxillary teeth, periodontal ligament, and alveolar. The models were designed to dissect the periodontal ligament, root, and alveolar separately. A 1.5 N force vector was loaded bilaterally to the center of the crown between first molar and canine, to retract the canine distally. The value of total deformation was used to assess the initial displacement of the canine and molar at the beginning of force loading. Stress intensity and force distribution were analyzed and evaluated by Ansys 13.0 through comparison of equivalent (von Mises) stress and maximum shear stress. Results: The maximum value of total deformation with the three kinds of models occurred in the distal part of the canine crown and gradually reduced from the crown to the apex of the canine; compared with the canines in model 3 and model 1, the canine in model 2 had the maximum value of displacement, up to 1.9812 mm. The lowest equivalent (von Mises) stress and the lowest maximum shear stress were concentrated mainly on the distal side of the canine root in model 2. The distribution of equivalent (von Mises) stress and maximum shear stress on the PDL of the canine in the three models was highly concentrated on the distal edge of the canine cervix. . Conclusions: Removal of the bone in the pathway of canine retraction results in low stress intensity for canine movement. Periodontal distraction aided by surgical undermining of the interseptal bone would reduce resistance and effectively accelerate the speed of canine retraction. .

Effect of piezopuncture on tooth movement and bone remodeling in dogs.

INTRODUCTION: The aim of the study was to elucidate whether a newly developed, minimally invasive procedure, piezopuncture, would be a logical modification for accelerating tooth movement in the maxilla and the mandible. METHODS: Ten beagle dogs were divided into 2 groups. Traditional orthodontic tooth movement was performed in the control group. In the experimental group, a piezotome was used to make cortical punctures penetrating the gingiva around the moving tooth. Measurements were made in weeks 1 through 6. Tooth movement and bone apposition rates from the histomorphometric analyses were evaluated by independent t tests. RESULTS: The cumulative tooth movement distance was greater in the piezopuncture group than in the control group: 3.26-fold in the maxilla and 2.45-fold in the mandible. Piezopuncture significantly accelerated the tooth movements at all observation times, and the acceleration was greatest during the first 2 weeks for the maxilla and the second week for the mandible. Anabolic activity was also increased by piezopuncture: 2.55-fold in the maxilla and 2.35-fold in the mandible. CONCLUSIONS: Based on the different effects of piezopuncture on the maxilla and the mandible, the results of a clinical trial of piezopuncture with optimized protocols might give orthodontists a therapeutic benefit for reducing treatment duration.

Sonosurgery for atraumatic tooth extraction: a clinical report.

The preservation of an intact labial plate during tooth extraction is a critical determinant of whether an immediate implant can be placed and is also an important predictor of the esthetic result. The purpose of this clinical report was to present a method for atraumatic tooth extraction by using an air-driven sonic instrument with specially designed inserts. This surgical technique provides the clinician with an efficient method for atraumatic tooth extraction and preservation of an intact labial plate.

Craniofacial bone tissue engineering.

There are numerous conditions, such as trauma, cancer, congenital malformations, and progressive deforming skeletal diseases, that can compromise the function and architectonics of bones of craniofacial region. The need to develop new approaches for treatment of these disorders arises from the fact that conventional therapeutic strategies face many obstacles and limitations. The use of tissue engineering in regeneration of craniofacial bone structures is a very promising possibility and a great challenge for researchers and practitioners. Developments in stem cell biology and engineering have led to the discovery of different stem cell populations and biodegradable materials with suitable properties. This review summarizes the current achievements in tissue engineering of craniofacial bone, temporomandibular joint, and periodontal ligament.

Exodontia: tips and techniques for better outcomes.

This article reviews and highlights exodontia tips as well as new techniques to make simple and complex exodontia more predictable and efficient with improved patient outcomes. A discussion of a powered periotome that has been developed to aid in the atraumatic extraction of teeth and another new device, the piezosurgery, increasingly used for outpatient oral surgery procedures are included. Physics forceps, a new type of exodontia forceps, is also discussed in this article.