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.

Pre-clinical evaluation of the effect of a volume-stable collagen matrix on periodontal regeneration in two-wall intrabony defects.

AIM: To histologically evaluate the effect of a new collagen matrix on periodontal regeneration. MATERIALS AND METHODS: Two-wall intrabony defects were surgically created bilaterally distally to the maxillary first and third pre-molars in beagle dogs. The defects were randomly allocated to open flap debridement either with (test) or without (control) a volume-stable collagen matrix (VCMX). After 12 weeks, the dogs were euthanized, and the specimens histologically processed. Descriptive, histomorphometrical (vertical gain of periodontal tissues) and statistical analyses were then performed. RESULTS: Healing was uneventful in most cases. Residual VCMX was still present and showed integration into new bone, new periodontal ligament, connective tissue and, in some specimens, into new cementum. Periodontal regeneration occurred to a varying extent in both groups. New continuous cementum and new bone formation were statistically significantly greater in the test group (4.12 mm and 3.28 mm, respectively) than in the control group (1.54 mm and 2.47 mm, respectively) (p = .009 and p = .037, respectively). The junctional epithelium was longer in the control group (2.21 mm) than in the test group (1.49 mm, p = .16). CONCLUSION: The present results have for the first time provided histologic evidence for the potential of this novel VCMX to facilitate periodontal regeneration thus warranting further pre-clinical and clinical testing.

Biomechanical effects of corticotomy facilitated orthodontic anterior retraction: a 3-dimensional finite element analysis.

The objective of this study was to assess the biomechanical effects of different corticotomy designs used for orthodontic anterior retraction through finite element analysis. MATERIALS AND METHODS: A basic finite element model simulating retraction of anterior teeth was built reversely from CBCT films of an adult patient with protruded maxillary anterior teeth. Another thirteen FE models were created according to different corticotomy designs varied with site width and the extent of incision. The initial displacement, Von Mises stress and pressure stress of dento-alveolar structures was computerized and analyzed. RESULTS: Corticotomy can increase the initial displacement of anterior segment including teeth and surrounding alveolar bone, change the distribution of Von Mises stress in cancellous bone and the pressure stress in periodontal ligament of anterior teeth. When the incision was near the periphery of apical, the anterior segment showed the greatest displacement, the cancellous bone at either sockets or incision region showed the maximum stress. Bilateral incision combined with palatal incision showed approximate initial displacement and stress distribution with circumscribing incision. While the incision width increased, the biomechanical effects of corticotomy amplified. CONCLUSIONS: Varied corticotomy designs can change the biomechanical effects on dento-alveolar structures. The incision near the periphery of apical and bilateral incision combined with palatal incision may be the optimized design used for retraction of anterior teeth.

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.

Extracellular Matrix Induces Periodontal Ligament Reconstruction In Vivo.

One of the problems in dental implant treatment is the lack of periodontal ligament (PDL), which supports teeth, prevents infection, and transduces sensations such as chewiness. The objective of the present study was to develop a decellularized PDL for supporting an artificial tooth. To this end, we prepared mouse decellularized mandible bone with a PDL matrix by high hydrostatic pressure and DNase and detergent treatments and evaluated its reconstruction in vivo. After tooth extraction, the decellularized mandible bone with PDL matrix was implanted under the subrenal capsule in rat and observed that host cells migrated into the matrix and oriented along the PDL collagen fibers. The extracted decellularized tooth and de- and re-calcified teeth, which was used as an artificial tooth model, were re-inserted into the decellularized mandible bone and implanted under the subrenal capsule in rat. The reconstructed PDL matrix for the extracted decellularized tooth resembled the decellularized mandible bone without tooth extraction. This demonstrates that decellularized PDL matrix can reconstruct PDL tissue by controlling host cell migration, which could serve as a novel periodontal treatment approach.

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.

Effect of periodontal ligament removal with gauze prior to delayed replantation in rabbit incisors on rate of replacement resorption.

BACKGROUND/AIM: Delayed (dry storage > 60 minutes) replantation results in ankylosis and replacement resorption. It has been suggested to remove the non-viable periodontal ligament before replantation to possibly reduce the rate of replacement resorption. However there has been no study on the rate of replacement resorption after such measures. The aim of this study was to investigate if there was any difference in the rate of replacement resorption by either removing the periodontal ligament (PDL) with gauze or not removing PDL in teeth subjected to delayed replantation followed by healing for 2 or 6 weeks. MATERIALS AND METHODS: Maxillary central incisors were extracted in 8 rabbits. In the right central incisors, the necrotic PDL was removed by dry gauze over the root surface. In the left eight extracted teeth PDL was left on the root surface. All extracted teeth were left to dry for 60 minutes. Extra-oral root canal treatment was performed before replantation. The rabbits were sacrificed after 2 weeks and 6 weeks respectively. Histologic processing and evaluation was done. RESULTS: In the 2 weeks group, all teeth showed ankylosis. The cementum was intact, and fusion of the bone and root was generally seen without resorption of the root, whereas in the 6 weeks group regardless of whether PDL had been kept or not, ankylosis and osseous replacement of the dentin was seen. There was no evidence of inflammatory infiltrate in the sections examined. CONCLUSION: Removal of PDL prior to delayed replantation may result in some initial protection of the cementum during the first few weeks. However, over longer times there seems to be neither protection of the dentin from ankylosis and osseous replacement, nor any influence on the rate of replacement resorption.

Periodontal Regenerative Treatment of Intrabony Defects in the Esthetic Zone Using Modified Vestibular Incision Subperiosteal Tunnel Access (M-VISTA).

Periodontal regenerative treatment of intrabony defects in the esthetic zone often poses a significant challenge to clinicians. Various materials and techniques have been proposed to achieve periodontal regeneration. This article presents modified vestibular incision subperiosteal tunnel access (M-VISTA) for treatment of intrabony defects in the esthetic zone. Two cases were treated using the proposed approach with enamel matrix derivatives and demineralized freeze-dried bone allograft to optimize the regenerative outcomes without affecting the soft tissue profile in the esthetic zone. Two different indications were described with addition of acellular dermal matrix and specific suturing techniques based on each particular clinical scenario. Clinical and radiographic follow-up of 18 months revealed successful outcomes of the proposed minimally invasive approach with no postoperative gingival recession. Patient-centered outcomes were highlighted as another major consideration in periodontal regeneration.

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.

Bio-implant as a novel restoration for tooth loss.

A dental implant is used to replace a missing tooth. Fixing the implant in its natural position requires the engineering of a substantial amount of conformal bone growth inside the implant socket, osseointegration. However, this conventional implant attachment does not include the periodontal ligament (PDL), which has a fundamental role in cushioning high mechanical loads. As a result, tooth implants have a shorter lifetime than the natural tooth and have a high chance of infections. We have engineered a "bio-implant" that provides a living PDL connection for titanium implants. The bio-implant consists of a hydroxyapatite coated titanium screw, ensheathed in cell sheets made from immortalized human periodontal cells. Bio-implants were transplanted into the upper first molar region of a tooth-extraction mouse model. Within 8 weeks the bio-implant generated fibrous connective tissue, a localised blood vessel network and new bone growth fused into the alveolar bone socket. The study presents a bio-implant engineered with human cells, specialised for the root connection, and resulted in the partial reconstruction of a naturalised tooth attachment complex (periodontium), consisting of all the principal tissue types, cementum, PDL and alveolar bone.

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.

Commentary: A Translational Medicine Approach to Tooth Transplantation.

The autogenous tooth transplantation approach to replace missing teeth has been in use for a long time. Different surgical techniques have been developed to improve prognosis and longevity of transplanted teeth with complete root formation. Many factors reportedly affected short- and long-term success of the procedure: complications such as ankylosis and root resorption up to the tooth exfoliation have occurred frequently. Several studies have appeared on this issue over the years. However, outcomes of transplantations have not yet been conclusively determined as no randomized clinical trials have been published on this issue, and their effectiveness has been evaluated only in observational studies. On the other hand, interesting information from specific experimental studies on the healing pattern of the interface between the root surface and alveolar bone in the replantation/transplantation model, and from non-related studies dealing with mechanically induced periodontal trauma, has been available and potentially useful since the 1970s to 1980s. However, this information has not been incorporated into clinical literature regarding tooth autotransplantation. This commentary aims to show how information from related and unrelated experimental models was translated to a clinical setting and led to a novel approach, successfully applied, in the autotransplantation of a multirooted tooth with completed root formation.

The Root Membrane Technique: Human Histologic Evidence after Five Years of Function.

BACKGROUND: The "root membrane" (RM) is a technique that has become popular among implantologists for placement of immediate implants in the anterior maxilla. PURPOSE: To present histologic evidence of an immediate implant placed in the human anterior maxilla, according to the RM technique, and retrieved after five years. METHODS: A fixture, along with the surrounding tissues, was retrieved from the anterior maxilla of a 68-year-old patient, who had been treated five years earlier with immediate implant placement and RM technique. The specimen was processed for histologic/histomorphometric evaluation. RESULTS: The buccal bone plate was maintained without any resorption; a healthy periodontal ligament was evidenced. The implant showed osseointegration, with a high percentage of bone-to-implant contact (BIC = 76.2%). With regard to the space between the RM and the implant, the apical and medial thirds were filled with compact, mature bone; the coronal third was colonized by noninfiltrated connective tissue. CONCLUSIONS: The RM technique appears to be effective in preventing bone resorption of the buccal bone plate of the human anterior maxilla, five years after the placement of an immediate implant.

[Different ways to remove necrotic periodontal ligament on delayed tooth replantation: scanning electron microscopy and histomorphometric analysis].

PURPOSE: To seek the most effective technique for removal of root-adhered periodontal ligament. METHODS: Thirty-five roots of healthy right mandibular first premolars extracted for orthodontic purposes were selected. After extraction, the teeth were kept dry at room temperature for at least 1 h, and then divided into five groups as follows: Group 1(control)-the root-adhered periodontal ligament was preserved; Group 2 (mechanical removal)-periodontal ligament remnants were removed by scraping root surface with a scalpel blade; Group 3 (chemical removal 1)-removal of the periodontal ligament by immersing the root in 1% sodium hypochlorite solution for 5 minutes; Group 4 (chemical removal 2)-removal of the periodontal ligament by immersing the root in 2% sodium hypochlorite solution for 5 minutes; Group 5 (chemical removal 3)-removal of the periodontal ligament by immersing the root in 1% sodium hypochlorite solution for 10 minutes. The specimens were analyzed histomorphometrically and examined under scanning electron microscopy. Both periodontal ligament remnants and preservation or removal of the cementum layer concomitantly with these procedures were assessed. The data were analyzed using one-way ANOVA and Tukey's test with SAS 8.02 software package. RESULTS: In regard to periodontal ligament remnants, group 1 presented the largest areas(P<0.05), group 2 showed smaller area than group 1 (P<0.05), but much larger than group 3-5 (P<0.05); The three chemical removal groups had no significant difference. As for preserved cementum layer, group 2 lost most areas, which showed the worst result(P<0.05). The other 4 groups had no significant difference. CONCLUSIONS: Scraping root surface with a scalpel blade could not wipe off the root-adhered periodontal ligament, and might damage the cementum layer. Sodium hypochlorite solution could clean up the periodontal ligament remnants and preserve cementum layer, which might be an ideal choice.

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.