Osteoradionecrosis in a Torus Mandibularis Treated by Antimicrobial Photodynamic Therapy: A Case Report.

Background: Osteoradionecrosis (ORN) of the jaws is a late complication after radiotherapy to head and neck cancer. Objective: To describe a rare case of ORN of the torus mandibularis that was successfully managed exclusively with antimicrobial photodynamic therapy (aPDT). Case report: A 72-year-old man presented an exposed necrotic bone observed in the torus mandibularis, extending to the lingual alveolar ridge with no edema nor suppuration. The treatment provided a noninvasive treatment leading to spontaneous sequestrectomy of the torus in 2 weeks with complete mucosal repair in 5 weeks and absence of lesion signs and/or symptoms even after 6 months of follow-up. Conclusions: The aPDT indicated to be a satisfactory treatment for ORN affecting torus mandibularis, a region with surgical limitations, avoiding surgery.

3D printing technology to produce intraoral stents for head and neck radiotherapy: A scoping review.

INTRODUCTION: Radiotherapy remains one of the main treatments for head and neck cancer; however, it is accompanied by acute and chronic adverse effects. Use of three-dimensional (3D) oral stents to modulate radiation intensity to specific target areas have been developed to minimize these adverse effects. This study aimed to present a scoping review of studies published on 3D printing of oral stents and their clinical applicability. METHODS: MEDLINE/Pubmed, Scopus, Web of Science and CENTRAL Cochrane data bases were searched, studies selected, and data collected by three independent reviewers up to December 2022. The review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-analysis-Extension for Scoping Reviews (PRISMA-ScR). RESULTS: The search resulted in 404 studies and 5 articles fulfilled the eligibility criteria and were considered for this review. Three-dimensional printed intraoral stents were produced for 56 patients with indication for radiotherapy. 3D-printed stents were well-tolerated by all tested patients and demonstrated great reproducibility of maxillomandibular relation, required less time for production and lower cost to manufacture. Two studies showed great protection of healthy tissues with 3D-printed stents during radiotherapy. CONCLUSIONS: Three-dimensional printing is promising for production of intraoral stents, however, more studies are needed to improve the technique and further investigate the safety and prevention of oral toxicities from radiotherapy.

Gingival cyst of the adult.

The gingival cyst of the adult (GCA) is a rare odontogenic cyst, consisting of 0.3% of all odontogenic cysts. This case report, based on CARE guidelines for case reports, aims to present a case of a 52-year-old female patient with a symptomatic translucent nodule in the upper left anterior gingiva, measuring approximately 6mm. Excisional biopsy was performed, and the histological examination revealed multiple cystic cavities lined by the squamous epithelium of varying thickness with focal areas of nodular thickenings. The presence of clusters of cells with clear cytoplasm within epithelial thickenings was observed. PAS staining was negative in clear cells. The diagnosis of the GCA was established. Despite its rarity, GCA should be considered in the differential diagnosis of gingival lesions. Conservative surgical treatment proved to be effective, with no signs of recurrence.

Osteoradionecrosis treatment in head and neck cancer patients: An overview of systematic reviews.

AIMS: Evaluate the existing evidence of osteoradionecrosis (ORN) treatment in adults with head and neck cancer, the methodological quality and the evidence grade within systematic reviews (SRs). METHODS: An extensive systematic literature search of SRs that addressed ORN in head and neck cancer patients was conducted with screening of eligible studies, data extraction, methodological (AMSTAR 2) and evidence quality assessment (GRADE) of the SRs by independent and calibrated authors. RESULTS: A total of six SRs were enrolled. Based primarily on studies from the 1990s, there is critically low- or moderate-quality evidence that hyperbaric oxygen therapy (HBO) improves ORN healing. From 2005 onward, evidence has been discovered in relation to treatment with pentoxifylline and tocopherol (PENTO). The SRs indicate that the management of ORN with PENTO appears to be promising. The greatest rates of healing are seen in mild and moderate stages of ORN. However, the quality of evidence regarding PENTO, surgery and other treatments remains critically low. CONCLUSION: There is no standardized protocol to treat ORN. PENTO appears to be the most promising conservative treatment; however, the current level of evidence regarding PENTO is still critically low. More robust clinical studies are needed to establish the best treatment for ORN.

Cytotoxicity, biocompatibility and osteoinductive profile of an MTA-hydrogel-based cement: An in vitro and animal study.

AIM: This study aimed to evaluate the cytotoxicity, biocompatibility and osteoinductive profile of a mineral trioxide aggregate (MTA)-hydrogel-based material (MTA Flow) in comparison with MTA Angelus. METHODOLOGY: Cell viability was evaluated in human periodontal ligament stem cells (hPDLSCs) using the methyl-thiazol-tetrazolium (MTT) colourimetric assay. Polyethylene tubes containing the tested materials and empty polyethylene tubes (control) were implanted in the subcutaneous tissue of Wistar rats. Cellular (lymphocyte infiltration) and extracellular events (ECM; collagen fibres) were analysed in histological sections. Immunohistochemical (collagen I, osteopontin, bone sialoprotein, bone morphogenetic protein4) analyses were also performed. RESULTS: At 24, 48 and 72 h, all tested groups showed cell viability similar to control (p > .05). Regarding biocompatibility, all groups showed similar cellular events represented by a slight inflammatory reaction characterized by hyperaemia and a mild lymphocytic inflammatory infiltrate. The analysis of lymphocytes during the time showed a decrease in these cells in the control group and a significant interaction between MTA Angelus and control (p < .001), with MTA Angelus showing a more extensive inflammatory infiltrate. Regarding fibres, an increase in content was observed in all groups during the experimental time (7, 30 and 60 days), however, no difference was detected among the experimental groups (p = .063). After 60 days, the immunoexpression of bone matrix proteins in the MTA Flow group was similar to or higher than that observed in the MTA Angelus and in the control group. CONCLUSIONS: MTA Flow showed a non-cytotoxic behaviour, biocompatibility and ability to stimulate tissue mineralization.

Synthesis of Submicrometric Chitosan Particles Loaded with Calcium Phosphate for Biomedical Applications.

Chitosan particles loaded with dibasic calcium phosphate anhydrous (DCPA) is a promising strategy for combining antimicrobial and osteoconduction properties in regenerative medicine. However, mostly micrometer-sized particles have been reported in the literature, limiting their use and reducing their effect in the biomedical field. We have recently overcome this limitation by developing submicrometer-sized particles with electrospray technique. The objective of this study was to understand how the process parameters control the size and properties of submicrometer chitosan particles loaded with DCPA. Solutions of 10 mg/mL chitosan and 2.5 mg/mL DCPA in a 90% acetic acid were electrosprayed under three distinct flow rate conditions: 0.2, 0.5, and 1.0 mL/h. The particles were crosslinked in a glutaraldehyde atmosphere and characterized in terms of their morphology, inorganic content, zeta potential, and minimum inhibitory concentration (MIC) against S. mutans. All conditions showed particles with two similar morphologies: one small-sized with a spherical shape and another larger-sized with a bi-concave shape. All generated a broad particle size distribution, with a similar mean size of ~ 235 nm. The addition of DCPA decreased the zeta potential for all the samples, but it was above 30 mV, indicating a low aggregation potential. The lower flow rate showed the worst efficacy for DCPA incorporation. Antimicrobial activity was greater in chitosan/DCPA particles with flow rate of 0.5 mL/h. It can be concluded that the flow rate of 0.5 mL/h presents the best compromise solution in terms of morphology, zeta potential, MIC, and inorganic content.

Gingival cyst of the adult

ABSTRACT The gingival cyst of the adult (GCA) is a rare odontogenic cyst, consisting of 0.3% of all odontogenic cysts. This case report, based on CARE guidelines for case reports, aims to present a case of a 52-year-old female patient with a symptomatic translucent nodule in the upper left anterior gingiva, measuring approximately 6mm. Excisional biopsy was performed, and the histological examination revealed multiple cystic cavities lined by the squamous epithelium of varying thickness with focal areas of nodular thickenings. The presence of clusters of cells with clear cytoplasm within epithelial thickenings was observed. PAS staining was negative in clear cells. The diagnosis of the GCA was established. Despite its rarity, GCA should be considered in the differential diagnosis of gingival lesions. Conservative surgical treatment proved to be effective, with no signs of recurrence.

Genotoxicity and Cytotoxicity Comparison of Calcium Silicate-Based and Resin-Based Sealers on Human Periodontal Ligament Stem Cells.

OBJECTIVE: This study aimed to assess the genotoxicity and cytotoxicity of Sealer Plus BC (SBC), AH Plus (AHP) and MTA Fillapex (MTF). METHODS: Human periodontal ligament dental stem cells (hPDLSCs) from third molars were isolated and cultured in a clonogenic medium. Cells were maintained in an incubator, and cell growth was monitored daily. hPDLSCs were characterised under flow cytometry and stem cell surface markers. The tested groups were a control group, SBC, AHP and MTF. Each sealer was prepared according to the manufacturer's instructions and placed in a clonogenic medium to produce a conditioned media. Conditioned media were then diluted to 10% to be placed in contact with culture cells in cell viability assay afterwards. The cells were harvested and plated into 96 wells culture plates. Genotoxicity was assessed by evaluation of micronucleus formation and cytotoxicity by MTT-based assay. All experiments were performed in triplicate. Data normality was verified by the Kolmogorov-Smirnov test. Statistical analysis for genotoxicity was performed with Kruskal-Wallis and Dunn's tests and two-way ANOVA for cytotoxicity, both with a significance level of 5%. RESULTS: Cells expressed typical levels of mesenchymal stem cell surface markers. No differences in the number of micronuclei were observed among all groups (P>0.05). In all periods analysed (24, 48, and 72 h), the sealers presented statistically different results for cell viability (P<0.05), with SBC presenting the lowest cytotoxicity, followed by the control group, MTF, and AHP. CONCLUSION: All sealers presented low genotoxicity, and Sealer Plus BC presented the lowest cytotoxicity.

Effects of the crosslinking of chitosan/DCPA particles in the antimicrobial and mechanical properties of dental restorative composites.

The development of restorative materials containing antibacterial agents is an alternative to reduce the progression of caries lesions. OBJECTIVE: to compare the influence of the degree of crosslinking of chitosan particles loaded with dibasic calcium phosphate (DCPA) on the mechanical properties, degree of conversion (DC), and antimicrobial properties of experimental composites. METHODS: Chitosan/DCPA particles were synthesized by the electrospraying, crosslinked by 0, 8, or 16 h in glutaraldehyde, and characterized by zeta potential and minimum inhibitory concentration (MIC) against S. mutans. Experimental resin composites of Bis-GMA and TEGDMA and 59.5% of barium glass were synthesized, chitosan/DCPA particles were added at 0 or 0.5 wt% with the different crosslinking time. The materials were subject to DC analysis, three-point bending test at 24 h and 7 days, and antimicrobial assays. Data were submitted to one-way ANOVA and Tukey test (α = 0.05). RESULTS: The particles with longer crosslinking time presented higher zeta potential and MIC, and the composite containing these particles showed significantly higher biofilm inhibition than the control group. The other two groups were similar to each other and the control. The composite containing particles with 88 h crosslinking time showed the lowest flexural strength at 7 days in water, and materials with non-crosslinked particles and longer crosslinking time presented flexural strength similar to control. The flexural modulus and DC showed no statistical difference among groups. SIGNIFICANCE: composite resin containing 0.5% chitosan/DCPA particles crosslinked by 16 h showed a reduction of biofilm formation without affecting the mechanical properties in relation to the control.

Pro-angiogenic potential of a functionalized hydrogel scaffold as a secretome delivery platform: An innovative strategy for cell homing-based dental pulp tissue engineering.

Angiogenesis is a key process that provides a suitable environment for successful tissue engineering and is even more crucial in regenerative endodontic procedures, since the root canal anatomy limits the development of a vascular network supply. Thus, sustainable and accelerated vascularization of tissue-engineered dental pulp constructs remains a major challenge in cell homing approaches. This study aimed to functionalize a chitosan hydrogel scaffold (CS) as a platform loaded with secretomes of stem cells from human exfoliated deciduous teeth (SHEDs) and evaluate its bioactive function and pro-angiogenic properties. Initially, the CS was loaded with SHED secretomes (CS-S), and the release kinetics of several trophic factors were assessed. Proliferation and chemotaxis assays were performed to analyze the effect of functionalized scaffold on stem cells from apical papilla (SCAPs) and the angiogenic potential was analyzed through the Matrigel tube formation assay with co-cultured of human umbilical vein endothelial cells and SCAPs. SHEDs and SCAPs expressed typical levels of mesenchymal stem cell surface markers. CS-S was able to release the trophic factors in a sustained manner, but each factor has its own release kinetics. The CS-S group showed a significantly higher proliferation rate, accelerated the chemotaxis, and higher capacity to form vascular-like structures. CS-S provided a sustained and controlled release of trophic factors, which, in turn, improved proliferation, chemotaxis and all angiogenesis parameters in the co-culture. Thus, the functionalization of chitosan scaffolds loaded with secretomes is a promising platform for cell homing-based tissue engineering.

aPDT for oral decontamination of hospitalized patients with COVID 19.

Emerging variants of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) may have an impact on the virus's transmissibility and pathogenicity and an increased risk of reinfection. Antimicrobial photodynamic therapy (aPDT) is a promising technique to decontaminate the oral cavity to minimize and inactivate microorganisms' load. This article reports through a case series, a proposal for efficient oral decontamination for hospitalized patients with COVID 19 using aPDT. Samples of oral tissues were obtained after aPDT and analyzed using two methods of RT-qPCR to elucidate qualitative and quantitative viral profiles of SARS-CoV-2 RNA in the oral cavity. There was a reduction of viral load in the oral cavity immediately or one hour after the use of aPDT. This method could be a good option to decontaminate the oral cavity to minimize and inactivate microorganism load.

Dental tissue-derived stem cell sheet biotechnology for periodontal tissue regeneration: A systematic review.

OBJECTIVE: This study aimed to conduct a systematic review of the use of a cell sheet formed by mesenchymal stem cells derived from dental tissues (ddMSCs) for periodontal tissue regeneration in animal models in comparison with any other type of regenerative treatment. DESIGN: PubMed and Scopus databases were searched for relevant studies up to December 2020. The review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. RESULTS: Of the 1542 potentially relevant articles initially identified, 33 fulfilled the eligibility criteria and were considered for this review. Even with a wide variety of selected study methods, the periodontal tissue was always regenerated; this indicates the potential for the use of these cell sheets in the future of periodontics. However, this regeneration process is not always complete. CONCLUSION: Despite the implantation, ddMSCs sheets have a great potential to be used in the regeneration of periodontal tissue. More in vivo studies should be conducted using standardized techniques for cell sheet implantation to obtain more robust evidence of the relevance of using this modality of cell therapy for periodontal tissue regeneration.

Effect of human dental pulp stem cell conditioned medium in the dentin-pulp complex regeneration: A pilot in vivo study.

BACKGROUND: Dental trauma, restorative operative procedures and/or caries lesions can expose the dental pulp. Facing this clinical condition, where the maintenance of the dentin-pulp complex vitality is imperative, is challenging in Dentistry. Dental pulp stem cells conditioned medium contains trophic factors that could help in this task. This in vivo pilot study aimed to evaluate the effects of the human dental pulp stem cells conditioned medium on the dental pulp tissue response to vital pulp therapy. MATERIAL AND METHODS: Concentrated conditioned medium was obtained by incubating characterized human dental pulp stem cells with fresh culture medium. Pulp exposures performed at the first upper molars (n = 20) of Wistar rats were directly capped with: MTA or MTA + Conditioned Medium. Four and 8 weeks later, the samples were qualitatively analyzed in histological sections (H&E). RESULTS: When the conditioned medium was associated with MTA, there were a high percentage of samples presenting formation of dentin bridges and small percentage of pulp tissue with inflammatory signs in both experimental times. The conditioned medium improved the organization of the newly formed hard tissue. CONCLUSIONS: The association of dental pulp stem cell conditioned medium with MTA showed beneficial effects on dentin-pulp complex regeneration and has promising potential for studies in regenerative dentistry.

Development and characterization of a new chitosan-based scaffold associated with gelatin, microparticulate dentin and genipin for endodontic regeneration.

OBJECTIVE: An ideal scaffold for endodontic regeneration should allow the predictableness of the new tissue organization and limit the negative impact of residual bacteria. Therefore, composition and functionalization of the scaffold play an important role in tissue bioengineering. The objective of this study was to assess the morphological, physicochemical, biological and antimicrobial properties of a new solid chitosan-based scaffold associated with gelatin, microparticulate dentin and genipin. METHODS: Scaffolds based on chitosan (Ch); chitosan associated with gelatin and genipin (ChGG); and chitosan associated with gelatin, microparticulate dentin and genipin (ChGDG) were prepared by using the freeze-drying method. The morphology of the scaffolds was analyzed by scanning electron microscopy (SEM). The physicochemical properties were assessed for biodegradation, swelling and total released proteins. The biological aspects of the scaffolds were assessed using human cells from the apical papilla (hCAPs). Cell morphology and adhesion to the scaffolds were evaluated by SEM, cytotoxicity and cell proliferation by MTT reduction-assay. Cell differentiation in scaffolds was assessed by using alizarin red assay. The antimicrobial effect of the scaffolds was evaluated by using the bacterial culture method, and bacterial adhesion to the scaffolds was observed by SEM. RESULTS: All the scaffolds presented porous structures. The ChCDG had more protein release, adhesion, proliferation and differentiation of hCAPs, and bacteriostatic effect on Enterococcus faecalis than Ch and ChGG (p < 0.05). SIGNIFICANCE: The chitosan associated with gelatin, microparticulate dentin and genipin has morphological, physicochemical, biological and antibacterial characteristics suitable for their potential use as scaffold in regenerative endodontics.

Biological Properties of Experimental Methacrylate-Based Sealers Containing Calcium Phosphates.

This study aimed to evaluate, in vitro and in vivo, the biocompatibility of experimental methacrylate-based endodontic sealers containing α-tricalcium phosphate (α-TCP) or nanostructured hydroxyapatite (HAp). Experimental methacrylate-based dual-cure sealers with the addition of α-TCP or HAp, at 10%wt were formulated and compared to AH Plus (AHP). Cell viability was assessed by 3-(4,5-dimethyl-thiazoyl)-2,5-diphenyl-tetrazolium bromide (MTT), and sulforhodamine B (SRB). Sealers were implanted in rats' subcutaneous tissue and histologically evaluated. Bioactivity was assessed by alkaline phosphatase enzyme activity (ALP) and Alizarin Red (AR), using apical papillary cells (SCAPs), and by the bone deposition measured in surgical cavities on rats' femur filled with AH Plus or α-TCP. In both viability assays, HAp and AHP sealers were similar, and α-TCP presented lower viability compared to the others at MTT assay (p<0.05). A gradual decrease of the inflammatory response according to the periods was observed and AHP was the only that presented giant cells (7-day period). Collagen fibers condensation increased according to the periods, with no differences among sealers. There was an increase at ALP activity and mineralized nodules deposition according to periods. HAp and α-TCP presented higher values for ALP activity at 5 days and at 5, 10, and 15 days for AR and were different from AHP (p<0.05). α-TCP presented superior values at 10 and 15 days compared to HAp and AHP for AR (p<0.05). At 90 days, α-TCP and control (empty cavity) showed high bone deposition compared to AHP (p<0.05). α-TCP and HAp, in a methacrylate-based sealer, presented biocompatibility and bioactivity, with the potential to be used as endodontic sealers in clinical practice. Further investigations are required to gain information on the physicochemical properties of these sealers formulation before its clinical implementation.

Physical and Biological Properties of a Chitosan Hydrogel Scaffold Associated to Photobiomodulation Therapy for Dental Pulp Regeneration: An In Vitro and In Vivo Study.

BACKGROUND: The regeneration of dental pulp, especially in cases of pulp death of immature teeth, is the goal of the regenerative endodontic procedures (REPs) that are based on tissue engineering principles, consisting of stem cells, growth factors, and scaffolds. Photobiomodulation therapy (PBMT) showed to improve dental pulp regeneration through cell homing approaches in preclinical studies and has been proposed as the fourth element of tissue engineering. However, when a blood clot was used as a scaffold in one of these previous studies, only 30% of success was achieved. The authors pointed out the instability of the blood clot as the regeneration shortcoming. Then, to circumvent this problem, a new scaffold was developed to be applied with the blood clot. The hypothesis of the present study was that an experimental injectable chitosan hydrogel would facilitate the three-dimensional spatial organization of endogenous stem cells in dental pulp regeneration with no interference on the positive influence of PBMT. METHODS: For the in vitro analysis, stem cells from the apical papilla (SCAPs) were characterized by flow cytometry and applied in the chitosan scaffold for evaluating adhesion, migration, and proliferation. For the in vivo analysis, the chitosan scaffold was applied in a rodent orthotopic dental pulp regeneration model under the influence of PBMT (660 nm; power output of 20 mW, beam area of 0.028 cm2, and energy density of 5 J/cm2). RESULTS: The scaffold tested in this study allowed significantly higher viability, proliferation, and migration of SCAPs in vitro when PBMT was applied, especially with the energy density of 5 J/cm2. These results were in consonance to those of the in vivo data, where pulp-like tissue formation was observed inside the root canal. CONCLUSION: Chitosan hydrogel when applied with a blood clot and PBMT could in the future improve previous results of dental pulp regeneration through cell homing approaches.