Effect of preradiation dental intervention on incidence of osteoradionecrosis in patients with head and neck cancer: A systematic review and meta-analysis

BackgroundThe purpose of this systematic review was to examine whether dental intervention involving bone or soft-tissue manipulation preradiotherapy (pre-RT) is associated with lower rates of osteoradionecrosis of the jaw (ORNJ) in patients with head and neck cancer (HNC).Types of Studies ReviewedThe authors included relevant studies from MEDLINE, Embase, and Cochrane Library, including observational studies published from 2007 through 2021 and involving adults who underwent dental intervention pre-RT for HNC. Authors assessed evidence certainty by using the Grading of Recommendations Assessment, Development, and Evaluation approach. Random-effects models were used to calculate pooled relative risk estimates and hazard ratios. When meta-analysis was not possible, study-level measures of association and narrative summaries of the evidence were reported.ResultsTwenty-two studies were included. From the pooled, unadjusted analysis, patients undergoing pre-RT extractions may have a 55% increased risk of experiencing ORNJ (relative risk, 1.55; 95% CI, 0.85 to 2.86; very low certainty); the unadjusted pooled hazard ratio was 3.19 (95% CI, 0.99 to 10.31; very low certainty), corresponding to a possible increased hazard of developing ORNJ (very low certainty). Findings for other pre-RT procedures manipulating bone or tissue relied on limited, observational studies with low or very low certainty evidence.ConclusionsMostly very low certainty evidence suggests that patients with HNC who need pre-RT dental intervention may have an increased risk of developing ORNJ compared with those who do not.Practical ImplicationsMaintaining optimal oral health may help reduce the need for urgent pre-RT dental treatment, potentially reducing ORNJ risk and minimizing delay of oncologic treatment in patients with HNC.     

Association between metabolic syndrome and tooth loss: A systematic review and meta-analysis

BackgroundThe authors conducted a systematic review and meta-analysis to verify the existence and level of scientific evidence concerning the association between metabolic syndrome (MetS), as the main exposure, and tooth loss (TL), as the outcome.Types of Studies ReviewedThrough electronic databases and partially through gray literature, the authors identified observational studies in adults. The authors used no date or language restrictions. The authors evaluated the studies’ methodological quality by using the Newcastle-Ottawa Scale. The authors conducted a random-effects model meta-analysis. The authors assessed the quality of evidence by using the Grading of Recommendations Assessment, Development and Evaluation criteria.ResultsTwelve studies met the eligibility criteria, and 9 were retained for the meta-analysis. Most were cross-sectional studies with good methodological quality. Participants with MetS had fewer teeth (standardized mean difference, −2.77; 95% confidence interval, −4.56 to −0.98) and an increased likelihood of lacking functional dentition (odds ratio, 2.37; 95% confidence interval, 1.89 to 2.96) than did those without MetS. The overall quality of evidence was very low.Conclusions and Practical ImplicationsBetter-conducted longitudinal studies are necessary to establish a causal relationship between MetS and TL to inform the best strategies to prevent TL in populations with MetS.     

National and international guidelines on the replacement of missing teeth with dentures for head and neck cancer patients post-radiotherapy: A rapid review

BackgroundReplacement of missing teeth is not a straightforward task in head and neck cancer (HNC) patients post-radiotherapy. There is debate regarding the best way to care for these patients as it has been reported that using dentures by HNC patients after receiving treatment with radiotherapy might initiate the development of osteoradionecrosis.AimThis rapid review aimed to collate and compare the national and international guidelines for the use of dentures following radiotherapy for HNC patients.Materials and methodsThree steps were included in data collection of this rapid review (first step; identification of dental and relevant non-dental associations/societies, second step, identification of national and international guidelines regarding the dental management of HNC patients, and third step; identification of recommendations about the replacement of missing teeth in HNC patients).ResultsIn the 193 countries recognized by the United Nations, there were 238 relevant societies found, from those 175 confirmed that they do not have clear guidelines. Only 32 associations/societies (all in either Europe and North America) recommend guidelines for their dentists (N = 12 guidelines) about the dental management of HNC patients and show their position regarding the use of dentures for HNC patients after receiving treatment with radiotherapy.ConclusionsThere are very few guidelines and those that do exist differ, lack detail, and rarely go beyond routine advice. Accordingly, clear, detailed, and evidence-based guidelines are required to inform the management of patients with missing teeth following radiotherapy for HNC patients.     

Baseline characteristics as 3-year predictors of tooth fracture and crack progression: Findings from The National Dental Practice-Based Research Network

BackgroundThe authors of this practice-based study estimated the risk of experiencing tooth fractures and crack progression over 3 years and correlated baseline patient-, tooth-, and crack-level characteristics with these outcomes.MethodsTwo-hundred-and-nine National Dental Practice-Based Research Network dentists enrolled a convenience sample of 2,601 participants with a cracked vital posterior tooth that had been examined for at least 1 recall visit over 3 years. Data were collected at the patient, tooth, and crack levels at baseline, annual follow-up visits, and any interim visits. Associations between these characteristics and the subsequent same-tooth fractures and crack progression were quantified.ResultsOf the 2,601 teeth with a crack or cracks at baseline, 78 (3.0%; 95% confidence interval, 2.4% to 3.7%) subsequently developed a fracture. Of the 1,889 patients untreated before year 1, 232 (12.3%; 95% confidence interval, 10.9% to 13.8%) had some type of crack progression. Baseline tooth-level characteristics associated with tooth fracture were the tooth was maxillary and had a wear facet through enamel and a crack was detectable with an explorer, on the facial surface, and in a horizontal direction. Crack progression was associated with males and teeth with multiple cracks at baseline; teeth with a baseline facial crack were less likely to show crack progression. There was no commonality between characteristics associated with tooth fracture and those associated with crack progression.ConclusionsDevelopment of tooth fractures and crack progression over 3 years were rare occurrences. Specific characteristics were associated with the development of tooth fracture and crack progression, although none were common to both.Practical ImplicationsThis information can aid dentists in assessing factors that place posterior cracked teeth at risk of experiencing adverse outcomes.     

The contribution of different permanent tooth types to untreated caries: Implications for public health surveillance and prevention

BackgroundUntreated caries (UC), although highly prevalent, is largely preventable. Information on the contribution of different teeth to UC prevalence and severity could be helpful in evaluating UC surveillance protocols and the relative benefits of caries prevention interventions.MethodsThe authors combined data from 3 cycles (2011-2016) of the National Health and Nutrition Examination Survey for participants aged 6 through 11 years, 12 through 19 years, 20 through 34 years, 35 through 49 years, 50 through 64 years, 65 through 74 years, and 75 years and older. For each age group the authors calculated the contribution of successive permanent tooth types (for example, first molars and second molars) to UC prevalence and severity.ResultsUC prevalence and the percentage of prevalence detected by means of screening molars were, respectively, 5% and 95% among participants aged 6 through 11 years; 16% and 92% among participants aged 12 through 19 years; 29% and 86% among participants aged 20 through 34 years; 26% and 70% among participants aged 35 through 49 years; 21% and 48% among participants aged 50 through 64 years; 16% and 36% among participants aged 65 through 74 years; and 17% and 25% among participants 75 years and older. Among adults aged 50 years and older, no teeth appeared to capture a disproportionate share of UC prevalence. Molars accounted for 87%, 79%, and 56% of severity among participants aged 6 through 11 years, 12 through 19 years, and 20 through 34 years, respectively. After age 34 years, molars accounted for less than 50% of severity.ConclusionsMolars are the tooth type most susceptible to UC well into adulthood.Practical ImplicationsMolars could be used as sentinel teeth for surveillance of UC and adults could benefit from caries prevention that targets molars.     

Clinical efficacy of a novel radiofrequency toothbrush for tooth stain reduction and tooth whitening: A randomized controlled trial

BackgroundThe authors aimed to evaluate the effect of a novel radiofrequency (RF) toothbrush on tooth stains and shades compared with a sonic vibrating toothbrush (CVS Health SmileSonic Pro Advanced Clean Sonic Toothbrush, Ranir) that earned the American Dental Association Seal of Acceptance.MethodsThe authors conducted a single-blind prospective study over 6 weeks. Participants were randomized to 1 of 2 study groups to receive either an RF toothbrush (ToothWave, Home Skinovations [test]) or a sonic vibrating toothbrush (SmileSonic powered toothbrush, Ranir [control]) and performed twice-daily toothbrushing with fluoridated toothpaste (Crest Cavity Protection, Procter & Gamble) for 6 weeks. Tooth stains and shades were assessed using the Lobene Stain Index and VITA Bleachedguide 3D-MASTER shade guide (VITA North America) at baseline and after 4 and 6 weeks of toothbrushing. In addition, the VITA Easyshade Advance 4.0 spectrophotometer (VITA North America) was used for shade evaluation. Safety was evaluated by means of oral soft-tissue examinations at each visit. Percentage reduction from baseline was compared between the groups. Statistical analyses were conducted using Mann-Whitney nonparametric model.ResultsEighty-six participants (43 in each group) completed the study with fully evaluable data. At baseline, the groups did not differ significantly in mean measurement scores. Percentage reductions of the measured scores were significantly greater (more extrinsic stain removal and whitening) in the test group than in the control group (P < .001). Both toothbrushes were well-tolerated, and no device-related adverse events were reported during the study.ConclusionsThe RF toothbrush produced substantial benefits in the reduction of tooth stains and whitening of tooth shade compared with a powered toothbrush (CVS Health SmileSonic Pro Advanced Clean Sonic Toothbrush, Ranir) that earned the American Dental Association Seal of Acceptance.Practical ImplicationsThe novel RF toothbrush is a safe and effective tool for stain removal and tooth whitening and can serve as an alternative to other whitening agents.This clinical trial was registered at ClinicalTrials.gov. The registration number is NCT03885609.     

The role of hemostatic agents after tooth extractions: A systematic review and meta-analysis

BackgroundHemostatic agents are used to control bleeding after tooth extraction and have been compared with conventional measures (that is, sutures or gauze pressure) in several studies. The objective of this systematic review was to evaluate the benefits of topical hemostatic agents for controlling bleeding after tooth extractions, especially in patients receiving antithrombotic therapy.Types of Studies ReviewedThe authors conducted a literature search in MEDLINE (PubMed), Scopus, and the Cochrane Central Register of Controlled Trials, including prospective human randomized clinical trials in which researchers compared hemostatic agents with conventional methods and reported the time to achieve hemostasis and postoperative bleeding events.ResultsSeventeen articles were eligible for inclusion. Hemostatic agents resulted in a significantly shorter time to achieve hemostasis in both healthy patients and patients taking antithrombotic drugs (standardized mean difference, –1.02; 95% CI, –1.70 to –0.35; P = .003 and standardized mean difference, –2.30; 95% CI, –3.20 to –1.39; P < .00001, respectively). Significantly fewer bleeding events were noted when hemostatic agents were used (risk ratio, 0.62; 95% CI, 0.44 to 0.88; P = .007). All forms of hemostatic agents (that is, mouthrinse, gel, hemostatic plug, and gauze soaked with the agent) had better efficacy in reducing the number of postoperative bleeding events than conventional hemostasis measures, except for hemostatic sponges. However, this was based on a small number of studies in each subgroup.ConclusionsThe use of hemostatic agents seemed to offer better bleeding control after tooth extractions in patients on antithrombotic drugs than conventional measures.Practical ImplicationsFindings of this systematic review may help clinicians attain more efficient hemostasis in patients requiring tooth extraction. This systematic review is registered in the PROSPERO database. The registration number is CRD42021256145.     

Correlation of plasma osteopontin and osteocalcin with lower renal function in dental patients with carotid artery calcification and tooth loss

ObjectivesTo investigate plasma osteopontin (OPN) and osteocalcin (OCN) levels in dental patients with carotid artery calcification (CAC) and determine the correlations between these proteins and renal function and tooth loss.MethodsThe health parameters and number of teeth of 99 participants were recorded. Panoramic radiographs were taken for CAC evaluation, and OPN and OCN levels were measured.ResultsNone of the participants had overt kidney disease, and 14 (14.14%) had CAC. The age, sex, and health profiles of patients with CAC were not different from those without CAC. The OPN and OCN levels in participants with CAC were higher than in those without (p = 0.026 and p = 0.025, respectively). The OPN levels were correlated with the estimated glomerular filtration rate (eGFR) (p = 0.021) and tooth loss (p = 0.027). The OCN levels were correlated with the eGFR (p = 0.002), tooth loss (p = 0.023), blood urea nitrogen (p = 0.040), and creatinine levels (p = 0.031). The median tooth loss in individuals with an eGFR <60 mL/min/1.73 m² was higher than that of individuals with an eGFR ≥60 mL/min/1.73 m² (p = 0.033). In individuals with CAC, tooth loss correlated more strongly with the eGFR, and the correlation between OPN and OCN levels was more apparent.ConclusionDental patients with CAC and increased tooth loss have a greater tendency for decreased renal function, which may be associated with OPN and OCN; thus, these patients should be referred for investigation.     

Muscle–bone relationship in temporomandibular joint disorders after partial discectomy

ObjectivesTemporomandibular joint osteoarthritis (TMJ-OA) causes degenerative changes in TMJ tissues. The inter-tissue crosstalk that exacerbates illness and organic changes in bone secondary to TMJ-OA potentially affects the muscles; therefore, patients with a muscular disease might also suffer from bone disease. However, knowledge gaps exist concerning muscle pathology at the onset of TMJ-OA. In this study, we documented the pathogeneses of the bone and muscle at the onset of TMJ-OA using a mouse model.MethodsWe performed a partial resection of the TMJ disk to establish a mouse model of TMJ-OA. After the onset of TMJ-OA, we performed various measurements at 8, 12, and 16 weeks post-surgery in the defined groups.ResultsThe volume of the mandibular head in the TMJ-OA group was significantly greater than that in the control group. The temporal muscles in the TMJ-OA group were significantly deformed compared with those in the control group; however, between-group comparisons did not reveal significant differences in the mandibular head or temporal muscles after surgery. Therefore, we hypothesized that the degree of mandibular head hypertrophy would alter the temporal muscles. A subsequent analysis of the correlation between the bone and muscle confirmed that the deformity of the temporal muscle increased with increasing hypertrophy of the mandibular head. Temporal and masseter muscle contact was observed in 25% of surgical groups.ConclusionsThis study demonstrates that TMJ-OA progressed when organic changes occurred in bones and muscles, supporting the symbiotic relationship between bones and muscles.     

A new supernumerary tooth occurring in the same region during follow-up after supernumerary tooth extraction: A case report

A supernumerary tooth (ST) is often detected in the childhood and a surgical approach is usually indicated for its management. Some cases may require orthodontic treatment after extraction; hence, a long-term follow-up is important. A 4-year-and-11-month-old Japanese boy was referred to our hospital for dental caries treatment. A radiographic examination at 5 years and 5 months revealed an ST near the maxillary left primary central incisor, which was later extracted. One year and 6 months after extraction, a metachronous new ST in the same region was detected. We highlight the importance of a regular radiographic examination after ST extraction.     

Regeneration processes of alveolar bone and microvascular changes after the application of platelet-rich fibrin

ObjectivesPlatelet-rich fibrin (PRF) is a promising agent for bone regeneration (BR). Platelets contain several growth factors that promote angiogenesis and BR. In this study, we observed the morphology of alveolar BR.MethodsPRF (Advanced PRF: A-PRF) was prepared by extracting 10 mL of blood from each dog in a collection tube before tooth extraction. The samples were centrifuged at 200 × g for 8 min and incubated for 10 min to allow clotting. The alveolar socket on the dentition's right side was densely filled with PRF. The opposite side, which did not receive PRF, served as the control group. Different methods were used for specimen preparation and observation. Sections stained with hematoxylin and eosin were observed under a light microscope. Bone specimens were observed using stereoscopic microscopy. The resin cast models were examined using a scanning electron microscope. Moreover, bone formation ratio and height were measured.ResultsFourteen days postoperatively, angiogenesis and bone deposition were more advanced in the PRF group than in the control group. Thirty days postoperatively, both groups developed porous bone. In the PRF group, new bone trabeculae (BT) and a network of blood vessels were formed in the bone marrow. Ninety days postoperatively, the resin cast showed a normal bone structure with BT and bone marrow. Thick BT were observed in the PRF group.ConclusionsGrowth factors in PRF stimulate microcirculation and promote angiogenesis and bone deposition. The benefits of PRF include safety and increased bone formation.     

Efficacy of artificial intelligence in the detection of periodontal bone loss and classification of periodontal diseases: A systematic review

BackgroundArtificial intelligence (AI) can aid in the diagnosis and treatment planning of periodontal disease by means of reducing subjectivity. This systematic review aimed to evaluate the efficacy of AI models in detecting radiographic periodontal bone loss (PBL) and accuracy in classifying lesions.Types of Studies ReviewedThe authors conducted an electronic search of PubMed, Scopus, and Web of Science for articles published through August 2022. Articles evaluating the efficacy of AI in determining PBL were included. The authors assessed the articles using the Quality Assessment for Studies of Diagnostic Accuracy tool. They used the Grading of Recommendations Assessment, Development and Evaluation criteria to evaluate the certainty of evidence.ResultsOf the 13 articles identified through electronic search, 6 studies met the inclusion criteria, using a variety of AI algorithms and different modalities, including panoramic and intraoral radiographs. Sensitivity, specificity, accuracy, and pixel accuracy were the outcomes measured. Although some studies found no substantial difference between AI and dental clinicians’ performance, others showed AI’s superiority in detecting PBL. Evidence suggests that AI has the potential to aid in the detection of PBL and classification of periodontal diseases. However, further research is needed to standardize AI algorithms and validate their clinical usefulness.Practical ImplicationsAlthough the use of AI may offer some benefits in the detection and classification of periodontal diseases, the low level of evidence and the inconsistent performance of AI algorithms suggest that caution should be exercised when considering the use of AI models in diagnosing PBL. This review was registered at PROSPERO (CRD42022364600).     

Biofilm on and structural damage of rotary cutting instruments after 5 cycles of clinical use and processing

BackgroundRotary cutting instruments (RCIs) are sterilized routinely. The authors aimed to analyze the structural integrity, presence of dirt, and microbial contamination of RCIs used in clinical practice after processing.MethodsEighty-four RCIs (42 carbide burs, 42 diamond burs) were divided into baseline, control, and test groups. The RCIs were evaluated by means of scanning electron microscopy and microbiological analysis. Evaluation criteria included presence of structural damage, dirt, biofilm, and isolated cells and their phenotypic profile.ResultsThe carbide burs from all groups and diamond burs from the test groups had structural damage. Dirt was observed in the baseline and test groups. Three bacterial species were isolated from 4 RCIs (9.52%). An isolated cell was observed from 1 carbide bur. Biofilm was observed on 3 RCIs (7.14%).ConclusionsRCIs should not be subjected to multiple uses; after the first clinical use they accumulate structural damage and dirt that hampers the cleaning step, causing failure in the sterilization process.Practical ImplicationsThe presence of microorganisms and structural damage on the RCIs confirmed that they are not amenable to processing, a fact that characterizes them as a single-use health care product.     

Vitamin C and eggshell membrane facilitate orthodontic tooth movement and induce histological changes in the periodontal tissue

ObjectivesCollagen remodeling of the periodontal tissue is an important mechanism that involves several biologically active substances to accelerate orthodontic tooth movement. It is known that Vitamin C (VC) enhances collagen production and induces tooth movement. Moreover, the eggshell membrane (ESM) is an integral component of various formulations used to promote wound healing. The purpose of our study was to determine the effects of combined treatment with VC and ESM on periodontal tissues during tooth movement.MethodsNine-week-old male osteogenic disorder Shionogi rats were randomized into four groups: control, VC, ESM, and VC + ESM. The control group was given tap water, and the VC, ESM, and VC + ESM groups were orally administered 0.1% VC solution, 1 wt% ESM solution, and a combination of 0.1 wt% VC and 1 wt% ESM solutions, respectively. A force of 25 or 75 g was applied for 10 days to produce orthodontic tooth movement. Distances of tooth movement were measured on days 3, 7, and 10 of treatment. Histological examination of the periodontal ligament was performed to determine the increase in type I and III collagen levels in response to treatment.ResultsDistances of tooth movement were significantly greater in the VC + ESM group than in the control group. The compression area of the alveolar bone showed increased osteoclastic activity and higher levels of bone resorption in the VC + ESM group. Expression levels of type I and III collagen in the tension area of the alveolar bone were higher in the VC + ESM group than in the control group.ConclusionsThis study revealed that the combined administration of VC and ESM accelerated tooth movement by protecting the periodontal tissue during orthodontic treatment. The combined clinical application of VC and ESM could potentially shorten orthodontic treatment time.     

Application of hiPSCs in tooth regeneration via cellular modulation

BackgroundInduced pluripotent stem cell (iPSC)-based technology provides limitless resources for customized development of organs without any ethical concerns. In theory, iPSCs generated from terminally differentiated cells can be induced to further differentiate into all types of organs that are derived from the embryonic germ layers. Since iPSC reprogramming technology is relatively new, extensive efforts by the researchers have been put together to optimize the protocols to establish in vitro differentiation of human iPSCs (hiPSCs) into various desirable cell types/organs.HighlightsIn the present study, we review the potential application of iPSCs as an efficient alternative to primary cells for modulating signal molecules. Furthermore, an efficient culture system that promotes the differentiation of cell lineages and tissue formation has been reviewed. We also summarize the recent studies wherein tissue engineering of the three germ layers has been explored. Particularly, we focus on the current research strategies for iPSC-based tooth regeneration via molecular modulation.ConclusionIn recent decades, robust knowledge regarding the hiPSC-based regenerative therapy has been accumulated, especially focusing on cellular modulation. This review provides the optimization of the procedures designed to regenerate specific organs.     

Impact of Medicaid dental coverage expansion on self-reported tooth loss in low-income adults

BackgroundLow-income adults delay oral health care due to cost more than any other health care service. These delays lead to caries, periodontal disease, and tooth loss. Expanding Medicaid dental coverage has increased dental visits, but the potential impact on previously unmet oral health needs is not well understood.MethodsIn this analysis, the authors estimated the association between Medicaid dental expansion and tooth loss. Data on self-reported tooth loss among adults below 138% federal poverty guideline were obtained from the Behavioral Risk Factor Surveillance System. A difference-in-differences regression was estimated. Additional analyses stratified according to age and separated extensive and limited dental benefits.ResultsExpanding Medicaid dental coverage is associated with increased probability of total tooth loss of 1 percentage point in the total sample, representing a 20% relative increase from the pre-expansion rate. This increase was concentrated in states offering extensive dental benefits and was largest (2.5-percentage-point greater likelihood) among adults aged 55 through 64 years for whom both extensive and limited dental benefits were associated with total tooth loss.ConclusionsMedicaid expansion with extensive dental benefits was associated with increased total tooth loss among low-income adults. This finding suggests that greater access to oral health care addressed previously unmet oral health needs for this population.Practical ImplicationsAs public dental coverage continues to expand, dental care professionals may find themselves treating a greater number of patients with substantial, previously unmet, oral health needs. Additional research to understand the long-term effects of Medicaid dental insurance for adults on their oral health is needed.     

Biological modification of tooth surface by laser-based apatite coating techniques

BackgroundDevelopment of new clinical regenerative procedures is needed for the reconstruction of the connective tissue attachment lost to periodontal disease. Apatite coating on the affected root surfaces could improve root surface biocompatibility and promote the reestablishment of connective tissue attachment.HighlightWe developed two novel techniques that use laser light for coating the tooth surface with apatite. In the laser-assisted biomimetic (LAB) process, a tooth substrate was placed in a supersaturated calcium phosphate solution and irradiated for 30 min with low-energy pulsed laser light. Due to the laser-assisted pseudo-biomineralization, a submicron-thick apatite film was created on the laser-irradiated tooth surface. Furthermore, we created a fluoride-incorporated apatite film on the tooth surface using the LAB process and demonstrated its antibacterial activity against Streptococcus mutans.In the laser-induced forward transfer with optical stamp (LIFTOP) process, a thin apatite film loaded with the cell-adhesion protein, fibronectin, was prepared beforehand as a raw material on the optical stamp (carbon- and polydimethylsiloxane-coated support) by a conventional biomimetic process. After irradiation with a single laser pulse, the film (microchip) was transferred onto a tooth substrate via laser ablation of the carbon sacrificial layer. The LIFTOP process requires only a short processing time and has a minimal heat effect on the film; thus, the film exhibits cell adhesion activity even after the LIFTOP process.ConclusionThe LAB and LIFTOP processes have the potential as novel tools for tooth surface modification in the treatment of periodontal disease.     

Advanced platelet-rich fibrin (A-PRF) has an impact on the initial healing of gingival regeneration after tooth extraction

ObjectivesPlatelet-rich fibrin (PRF) is widely used in wound healing because it contains several growth factors, including vascular endothelial growth factor (VEGF). In this study, we investigated the effects of advanced PRF (A-PRF) in early-stage gingival regeneration after tooth extraction.MethodsBlood sample was collected from females beagle dogs (age: 12 months) before tooth extraction for A-PRF preparation. All animals were sacrificed by perfusion-fixation on postoperative days 1, 3, and 7. The upper jaws were prepared for hematoxylin and eosin staining and immunostaining (for CD34 and VEGF). The lower jaw samples were prepared for scanning electron microscope observations. Blood flow in the gingiva before and after surgery was measured using laser Doppler flowmetry.ResultsIn the A-PRF group, a large number of microvessels were observed in the gingival tissue on postoperative day 1. The microvessels in the control group were fewer and sparse. Regarding the vascular resin cast, a large number of new blood vessels were observed on postoperative day 1 in the A-PRF group. A stronger CD34-positive signal was obtained around the blood vessels in the A-PRF group than in the control group. Further, a strong VEGF-positive signal was observed in the perivascular tissue in the A-PRF group. Gingival blood flow was significantly higher in the A-PRF group after surgery.ConclusionA-PRF had a positive impact on angiogenesis in the gingiva through the induction of VEGF expression. Thus, A-PRF may be beneficial for gingival tissue regeneration.     

Biochemical and X-ray micro-computed tomographic analyses of critical size bone defects grafted with autogenous bone and mercerized bacterial cellulose membranes salified with alendronate

ObjectivesThis study aimed to evaluate the repair of critical-sized bone defects grafted with autogenous bone and mercerized bacterial cellulose membranes (BCm) salified with alendronate (ALN).MethodsForty-eight male Wistar rats underwent surgery to create a 5 mm-diameter bone defect in the calvarium. The removed bone was particularized, regrafted into the defect, and covered by a BCm according to the group: control group (CG), simply mercerized BCm; group 1 (G1), negatively charged BCm (BCm-CM^-) salified with ALN; and group 2 (G2), positively charged BCm (BCm-DEAE⁺) salified with ALN. Serum samples were collected preoperatively and before euthanasia to analyze osteoprotegerin (OPG), parathyroid hormone (PTH), sclerostin (SOST), and fibroblast growth factor 23 (FGF23) levels. The animals were euthanized after 15 or 60 d. Calvaria were analyzed using quantitative microtomography (μCT).ResultsThere was an increased level of PTH in the CG compared to the G2 group, at day 60 (p = 0.019). When analyzing the same group over time, G1 presented an increased FGF23 level on days 15 and 60 (p < 0.05). CG presented an increase in PTH (p = 0.037) at day 60. The μCT analysis detected increased trabecular separation on day 15 in G2 compared to G1 (p = 0.040).ConclusionsSalification of ionized BCm with ALN had no direct effect on bone repair; however, BCm-CM^- increased the levels of FGF23 over time. BCm-DEAE⁺ decreased PTH levels compared to mercerized BCm. BCm-CM-salified with ALN-induced superior bone quality, with respect to trabecular separation, compared to BCm-DEAE⁺.