Application effect of computer-aided design combined with three-dimensional printing technology in autologous tooth transplantation: a retrospective cohort study

Background The activity of donor periodontal membrane is the key factor of autologous tooth healing. The application of digital aided design, 3D printing model and guide plate in autotransplantation of tooth (ATT) is expected to reduce the damage of periodontal membrane and preserve the activity of periodontal membrane, so as to improve the success rate of ATT. This study tried to prove the role of digital technology in improving the success rate of ATT, although there are differences in model accuracy in practice. Methods We included 41 tooth autotransplantation cases which assisted by 3D-printed donor models and surgical guides and divided them into two groups in accordance with whether the donor tooth could be placed successfully after the preparation of alveolar socket guided by the model tooth. Then, we compared and analyzed the preparation time of alveolar socket, extra-alveolar time, and number of positioning trials of the donor tooth between the two groups. We also included a comparison of the in vitro time of the donor tooth with that of 15 min. The incidence of complications was included in the prognostic evaluation. Results The mean preparation time of the alveolar socket, mean extra-alveolar time of donor tooth, and mean number of positioning trials with donor tooth of 41 cases were 12.73 ± 6.18 min, 5.56 ± 3.11 min, and 2.61 ± 1.00, respectively. The group wherein the donor tooth cannot be placed successfully (15.57 ± 6.14 min, 7.29 ± 2.57 min) spent more preparation time of alveolar socket and extra-alveolar time than the group wherein the donor tooth can be placed successfully (9.75 ± 4.73 min, 3.75 ± 2.57 min). The number of positioning trials with the donor tooth of the group wherein the donor tooth cannot be placed successfully (3.19 ± 0.75) was higher than that of the other group (2.00 ± 0.86). There was no significant difference in survival rates between the two groups. Conclusions Compared with the traditional tooth autotransplantation, the introduction of computer-aided design combined with 3D printing of the model tooth and surgical guides evidently shortens the preparation time of the alveolar socket and the extra-alveolar time of the donor tooth and reduces the number of positioning trials with the donor tooth regardless of the shape deviation between the model and actual teeth.

Fibroma cementoossificante bilateral mandibular apresentando diferentes estágios de maturação: relato de caso clínico / Bilateral ossifying fibroma of the jaw with different maturation stages: a case report

The ossifying fibroma (OF) is characterized as a benign neoplasm originated from the mesenchymal periodontal membrane, being composed of different amounts of mineralized material and fibrocellular stroma, leading to a mixed aspect. More commonly found as solitary lesions, the OF can be multiple in rare cases, normally associated with hyperparathyroidism-jaw tumor syndrome (HPT-JT). The aim of this study is to report a case of bilateral OF in the mandible with different stages of maturation, not associated with HPT-JT. This case shows a 20-year-old female patient with asymptomatic intraoral hard swelling in both sides of the mandible, presenting a slight expansion in the buccal bone cortex, near to the molars, hard to palpation. CBCT showed a unilocular, well-circumscribed hypodense image, with calcified masses only on the right side. Incisional biopsies were performed and a diagnosis of bilateral OF was reached. Due to the different stages of maturation of the lesions, two different surgical approaches were performed, curettage in the left side and surgical resection in the right side with extraction of the lower second premolar and lower first molar. These areas were restored with bone grafts and the left first molar was unresponsive to the pulp vitality test and endodontic treatment was performed. The patient is undergoing periodic clinical and radiographic follow-up, and after 12 months no signs or evidence of recurrence were observed.

Progranulin promotes osteogenic differentiation of periodontal membrane stem cells in both inflammatory and non-inflammatory conditions

Objective The growth factor progranulin (PGRN) is widely expressed and plays important roles in anti-inflammatory signaling and bone regeneration. However, the anti-inflammatory and pro-osteogenic roles of PGRN in periodontitis are seldom studied. We used an in vitro model to investigate whether PGRN can promote osteogenic differentiation of periodontal ligament stem cells (PDLSCs). Methods PDLSCs were treated with PGRN (0 to 100 ng/mL) and the optimal concentrations required to induce proliferation and osteogenesis were identified. PDLSCs were cultured with 10 ng/mL tumor necrosis factor (TNF)-α, 25 ng/mL PGRN, or 10 ng/mL TNF-α + 25 ng/ml PGRN; untreated PDLSCs were used as controls. The effects of PGRN on PDLSC proliferation and osteogenic differentiation were assessed. Results PGRN (5, 25, and 50 ng/mL) promoted PDLSC proliferation and osteogenic differentiation, with the 25-ng/mL dose showing the largest effect. Furthermore, 25 ng/mL PGRN reversed inhibition of osteogenic differentiation by TNF-α. Conclusion PGRN promotes PDLSC proliferation, osteogenic differentiation, and mineralization in both inflammatory and non-inflammatory conditions. The 25-ng/mL PRGN dose was the most suitable for inducing proliferation and osteogenesis. Further studies using animal models will be required to obtain pre-clinical evidence to support using PGRN as a treatment for periodontitis.

A rare case of peripheral giant cell granuloma

Peripheral Giant Cell Granuloma or the so called “Giant Cell Epulis” is the most common oral giant cell lesion. It is described as non-neoplastic, hyperplastic lesion occurring exclusively on gingival/alveolar crest that appears as a overgrowth of tissues, following trauma or irritation arising from periosteum or periodontal membrane. It can be sessile or pedunculated with size usually less than 2cm. Although being uncommon, this lesion carries a lot of uncertainity in terms of its etiology, growth potential, biological behavior (recurrence), histogenesis of its cells and its treatment. We hereby report a case of a 49-year old male patient, with peripheral giant cell granuloma in mandibular posterior region, who was successfully treated and is on regular follow up since 6 months.

Aggressive behavior of peripheral giant cell granuloma: A case report

Background: Peripheral Giant Cell Granuloma (PGCG) considered one of the commonest oral giant cell lesions and gingival epulis. It is probably a non neoplastic lesion but rather reactive in nature which originates from the periodontal membrane or the periosteum as a reaction to chronic trauma or local irritation. This article reports a case of PGCG in a 6 years old male patient complaining of massive gingival swelling associated with looseness of related teeth which is highly unlikely to occur with such lesions, that may lead to misdiagnosis. Material and method: Surgical excision followed by histopathological examination was performed and confirmed using CD34 and CD45 for detection and confirming the origin of multinucleated giant cells (MNGCs). Results: Immunopositivity for CD34 was demonstrated only as cytoplasmic reaction of endothelial cells lining blood vessels while negative reaction was observed in MNGCs or in stromal mononuclear cell. Moreover, cytoplasmic immunoreactivity for CD45 was revealed in MNGCs and few stromal cells. Conclusion: Correlating clinical, radiographic and histopathologic examination reaching definite and early diagnosis is mandatory for management of such lesions thus eliminating potential risk of damaging to adjacent hard tissue structures. Keywords: Peripheral giant cell granuloma; multinucleated giant cells; CD34; CD45.

Combination of SDF-1 and bFGF promotes bone marrow stem cell-mediated periodontal ligament regeneration

Stromal cell derived factor-1 (SDF-1) and basic fibroblast growth factor (bFGF) were reported to induce the differentiation of bone marrow stem cells (BMSCs) into cells with characteristics of periodontal ligament fibroblasts. Thus SDF-1 and bFGF may play a positive role in BMSCs-mediated periodontal ligament regeneration. Here, the methylthiazolyldiphenyl tetrazolium bromide (MTT) assay was used to investigate the effect of scaffolds, SDF-1 and bFGF on BMSCs proliferation. RT-PCR and Western blot were used to evaluate gene and protein expression. Beagle dogs were used to establish an animal model of tooth reimplantation and to investigate the effects of scaffolds, BMSCs, SDF-1 and bFGF on periodontal ligament regeneration. X-ray images and micro computed tomography (micro CT) were used to assess morphological changes in replanted teeth and surrounding alveolar bone. H&E staining and Masson’s staining were also performed. BMSCs from Beagle dogs growth on scaffolds consisted of dense structured collagens. SDF-1 and bFGF effectively promoted the differentiation of BMSCs into fibroblasts, periodontal membrane reconstruction, and cell proliferation in vitro. SDF-1 and bFGF also stimulated the expression of type I collagen (Col I), type III collagen (Col III), CXC family chemokine receptor 4 (CXCR4), and S100 calcium binding protein A4 (S100A4), and decreased the expression of alkaline phosphatase (ALP). In our experimental Beagle dog model of tooth extraction and replantation, application of SDF-1 and bFGF significantly elevated periodontal membrane reconstruction and thus supported the survival of replanted teeth. In conclusion, the findings from the present study demonstrated that SDF-1 and bFGF enhance the process of periodontal ligament reconstruction, and provide a basis and reference for the use of stem cell tissue engineering in promoting periodontal membrane regeneration.

A Histological Study of Vasoconstriction by Local Anesthetics in Mandible

To assess the effect of epinephrine-containing local anesthetics on vasoconstriction, we immunohistochemically measured the intravascular lumen area in different regions of the mandible. Twelve male Wistar rats were used. General anesthesia was induced and maintained with sevoflurane. Infiltration anesthesia was performed with 0.2 mL of epinephrine-free 2% lidocaine (E−) near the left mandibular first molar and with 0.2 mL of epinephrine-containing 2% lidocaine (E+) near the right mandibular first molar. After decalcification, the specimens were paraffinized, and thin sections were prepared and immunohistologically stained with an antismooth muscle actin antibody. The intravascular lumen area was measured in the mucosa, periodontal membrane, Haversian/Volkmann's canal, and bone marrow. A Mann-Whitney U test was used for statistical processing, and p < .05 was considered to indicate a statistically significant difference. In the oral mucosa and the periodontal membrane, E+ had a significantly smaller vascular lumen area than E−. In the Haversian/Volkmann's canal and the bone marrow, no significant intergroup difference was observed in the intravascular lumen area. We postulate that this is due to a low smooth muscle content of blood vessels in the mandible and suggest that the vasoconstrictive effect of epinephrine-containing local anesthetics within the mandible is ineffective.