Photobiomodulation in dental extraction therapy: Postsurgical pain reduction and wound healing

BackgroundThis scoping review and analysis were designed to assess the amount of time spent delivering photobiomodulation (PBM) light therapy after dental extraction to improve postoperative pain and wound healing.Types of Studies ReviewedThe scoping review was performed according to the Cochrane Collaboration and Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. Publications were specific for human randomized controlled clinical trials, PBM after dental extraction therapy, and related clinical outcomes. Online databases searched included PubMed, Embase, Scopus, and Web of Science. Analyses were conducted to analyze the prescribed intervals of time (seconds) per application of PBM.ResultsOf the 632 studies initially identified, 22 studies fulfilled the inclusion criteria. Postoperative pain and PBM were reported in 20 articles for 24 treatment groups, with treatment times ranging from 17 through 900 seconds and wavelengths from 550 through 1,064 nm. Clinical wound healing outcomes were reported in 6 articles for 7 groups with treatment times ranging from 30 through 120 seconds and wavelengths from 660 through 808 nm. PBM therapy was not associated with adverse events.Conclusions and Practical ImplicationsThere is future potential to integrate PBM after dental extraction therapy to improve postoperative pain and clinical wound healing. The amount of time spent delivering PBM will vary by wavelength and the type of device. Further investigation is needed to translate PBM therapy into human clinical care.     

Homogeneity of dental curing unit beam profile and its effect on microhardness of dental composites with varying thicknesses

ObjectivesThe dental curing unit (DCU) has been reported to emit inhomogeneous light. However, there are no studies on which elements could affect the inhomogeneity of DCUs. This study aimed to analyze the effect of attenuating factors such as the aperture of the lens or neutral density (ND) filters on the DCU's beam profile and evaluate the effect of DCU's inhomogeneous beam profile on the microhardness distribution on composite resin specimens with different thicknesses.MethodsRadiant emittance and spectrum of eight DCUs were investigated with and without ND filters using different optical density (OD) values. Beam profiles of eight DCUs were photographed while increasing the OD values of the ND filter. The change in the beam profile while changing the f-number of the aperture and the OD value of the ND filters were recorded. The Vickers microhardness of Filtek Z350XT and SDR cured by Bluephase Style 20i with 1, 2, 3, and 4 mm specimens of nine points on each surface was measured.ResultsIrradiance and spectrum of DCUs uniformly decreased after attenuation by the ND filters. The beam profile of the DCUs blurred when the f-number of the aperture was higher. The microhardness of Filtek Z350XT showed differences between the central and peripheral areas, and between the points under violet LED and the center on the bottom surface of the 4 mm specimen. The microhardness of the SDR did not show any differences.SignificanceThe inhomogeneity of the beam profile can be affected by attenuation conditions. DCU's inhomogeneous beam profile may have different effects on the composites depending on the thicknesses and types of composite resin used.     

Surgical guides for esthetic crown lengthening procedures: Periodontal and prosthetic aspects

BackgroundIn patients with gingival exposure on smiling due to altered passive eruption, esthetic crown lengthening is often indicated. Meticulous planning and surgical precision are key for successful outcomes. Surgical guides are helpful tools that are seldomly reported on in the literature related to esthetic crown lengthening procedures.Types of Studies ReviewedThe authors searched the literature for articles that described the planning, tools, and execution related to esthetic crown lengthening procedures.ResultsSeveral techniques have been reported to guide the esthetic crown lengthening procedure, ranging from direct bone level measurement to 3-dimensional printed surgical guides.Practical ImplicationsThis review serves the clinician as an aid in the decision-making process for esthetic crown lengthening procedures and available surgical guide options, including computer-based guides.     

Efficacy of oscillating rotating versus side-to-side powered toothbrushes on plaque and gingival index reduction: A systematic review

BackgroundThe authors conducted a systematic review to assess the efficacy of oscillating rotating (OR) versus side-to-side (SS) powered toothbrushes on plaque and gingival index reduction.MethodsThe authors searched 3 electronic databases and the gray literature for randomized clinical trials in which investigators compared OR with SS powered toothbrushes. Two authors independently screened the studies, performed data abstraction, and assessed the risk of bias. The authors used random-effects model meta-analyses to pool results across trials and the Grading of Recommendations Assessment, Development and Evaluation approach to rate the certainty of evidence.ResultsThis systematic review included 24 trials in which researchers enrolled a total of 2,998 patients. There was moderate-certainty evidence that SS toothbrushes may result in little to no difference in plaque index reduction from baseline to 4 weeks compared with OR toothbrushes (standardized mean difference, 0.02; 95% confidence interval, –0.46 to 0.42). There was moderate-certainty evidence that SS toothbrushes may result in little to no difference in gingival index reduction from baseline to 4 weeks compared with OR toothbrushes (standardized mean difference, 0.13; 95% confidence interval, –0.47 to 0.22). There was moderate-quality evidence suggesting little to no difference in adverse events.ConclusionsThe evidence does not suggest the superiority of either OR or SS toothbrushes for plaque or gingival index reduction.Practical ImplicationsClinicians and patients considering the use of either of these toothbrushes are unlikely to observe more benefits with one type versus the other.     

Antiplaque and antigingivitis efficacy of cetylpyridinium chloride with zinc lactate compared with essential oil mouthrinses: Randomized clinical trial

BackgroundThe authors of this study aimed to evaluate the clinical antiplaque and antigingivitis effects of 3 oral hygiene regimens: toothbrushing with standard fluoride toothpaste and manual toothbrush and using a mouthrinse containing cetylpyridinium chloride, zinc lactate, and fluoride (CPC + Zn + F) in an alcohol-free base; toothbrushing with standard fluoride toothpaste and manual toothbrush and using a mouthrinse containing essential oils (EO) in an alcohol-free base; and toothbrushing with manual toothbrush and standard fluoride toothpaste and manual toothbrush (control).MethodsThe participants (N = 120) were randomly assigned to study groups and followed the assigned regimens twice daily for 6 weeks. The participants were examined by a calibrated examiner for the Quigley-Hein plaque index (Turesky modification) and Löe-Silness gingival index at baseline, week 4, and week 6. Statistical analyses were performed separately for plaque and gingival indexes by means of analysis of variance, paired t test, and analysis of covariance (α = 0.05).ResultsAt week 4, the CPC + Zn + F group presented additional reductions in dental plaque compared with EO and control groups of (21.4% [P < .001] and 31.4% [P < .001], respectively). After 6 weeks, these values were 26.7% (P < .001) and 44.8% (P < .001), respectively. For Löe-Silness gingival index, additional reduction in the CPC + Zn + F group compared with EO were 10.6% (P < .001) and 13.7% (P < .001) at 4 and 6 weeks, respectively. Compared with control, these reductions were 13.6% (P < .001) and 17.8% (P < .001), respectively.ConclusionsThe regimen including a mouthrinse containing CPC + Zn + F presented higher antiplaque and antigingivitis effects than EO and control regimens.Practical ImplicationsA mouthrinse containing CPC + Zn + F is an effective protocol for the control of dental plaque and gingivitis.     

Healing of experimental gingival recession defects treated with amnion allograft: Histologic and histometric analysis in dogs

ObjectivesThis study was conducted to compare the healing response of localized gingival recession defects treated with a coronally advanced flap (CAF) and either an amnion allograft membrane (AM) or a connective tissue graft (CTG).MethodsGingival recession defects were surgically created in six healthy mongrel dogs at the labial root surface of the maxillary canines, bilaterally. Using a split mouth design, the defects were treated with CAF and either AM (CAF/AM) or CTG (CAF/CTG). Three animals for each group were scarified at 1 and 3 months. Segments containing the defects were prepared for histological and histometric analysis.ResultsBoth techniques showed similar clinical findings with adequate root coverage. Histologically, healing was characterized by the formation of new cementum and new connective tissue attachment in the CAF/AM group; in the CAF/CTG group, healing was characterized by junctional epithelium, coronally, and connective tissue fibers parallel to the root surface, apically. Histometrically, the CAF/AM group revealed a substantially shorter epithelial length and a longer, new cementum compared with those of the CAF/CTG group after a healing period of 3 months.ConclusionsWithin the limits of this study, we concluded that the AM allograft could promote periodontal healing in gingival recession defects.     

Systematic review and meta-analysis of randomized controlled studies comparing oscillating-rotating and other powered toothbrushes

BackgroundThe aim of this study was to systematically review and analyze the difference in efficacy of oscillating-rotating toothbrushes compared with other powered toothbrushes.MethodsThe authors performed a systematic search of the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The authors used the population, intervention, comparison, and outcome format to develop a search strategy to answer the study question. The authors searched PubMed-MEDLINE databases. Inclusion criteria were randomized controlled clinical trials comparing oscillating-rotating (OR) toothbrushes with other powered toothbrushes published from January 1, 2009 through March 1, 2019.ResultsThe authors’ search resulted in 454 articles; 21 articles were downloaded for review, 15 articles were included in the report, and 12 could be used for meta-analysis. All of the studies were randomized controlled clinical trials that assessed plaque removal and gingival inflammation indexes. Results of the meta-analysis of the randomized controlled clinical trials showed that OR toothbrushes had superior, statistically significant outcomes for whole-mouth plaque reduction, assessed using the Rustogi Modified Navy Plaque Index (P < .01), and gingivitis, assessed by using number of bleeding sites (P < .001), but not for the modified gingival index (P > .05) or gingival bleeding index (P > .05).Practical ImplicationsThere is some evidence to suggest that OR powered toothbrushes might remove more plaque and reduce the number of bleedings sites better than other powered toothbrushes, specifically, sonic action toothbrushes.     

Characterization of silver diamine fluoride cytotoxicity using microfluidic tooth-on-a-chip and gingival equivalents

ObjectiveThis study aims to characterize the cytotoxicity potential of silver diamine fluoride (SDF) on dental pulp stem cells (DPSC) and gingival equivalents.MethodsDPSC cultured on 96-well plates was exposed directly to SDF (0.0001–0.01%) and cell viability (IC₅₀) quantified. Effect of SDF on DPSC viability under flow (with dentin barrier) conditions was evaluated using a custom-designed microfluidic "tooth-on-a-chip”. Permeability of dentin discs (0.5–1.5 mm thickness) was evaluated using lucifer yellow permeation assay. Dentin discs were treated with 38% SDF (up to 3 h), and cell viability (live/dead assay) of the DPSC cultured in the inlet (unexposed) and outlet (exposed) regions of the pulp channel was evaluated. To assess the mucosal corrosion potential, gingival equivalents were treated with 38% SDF for 3 or 60 min (OECD test guideline 431) and characterized by MTT assay and histomorphometric analysis.ResultsDPSC exposed directly to SDF showed a dose-dependent reduction in cell viability (IC₅₀: 0.001%). Inlet channels (internal control) of the tooth-on-a-chip exposed to PBS and SDF-exposed dentin discs showed> 85% DPSC viability. In contrast, the outlet channels of SDF-exposed dentin discs showed a decreased viability of< 31% and 0% (1.5 and ≤1.0 mm thick dentin disc, respectively) (p < 0.01). The gingiva equivalents treated with SDF for 3 and 60 min demonstrated decreased epithelial integrity, loss of intercellular cohesion and corneal layer detachment with significant reduction in intact epithelial thickness (p < 0.05).SignificanceSDF penetrated the dentin (≤1 mm thick) inducing significant death of the pulp cells. SDF also disrupted gingival epithelial integrity resulting in mucosal corrosion.     

Critical features of periodontal flaps with regard to blood clot stability: A review

BackgroundWound healing is a multifactorial procedure involving different cell types and biological mediators. The principles of wound healing are also applicable to periodontal tissues. The formation and stability of blood clots play a vital role in successful healing of wounds in periodontal tissues. The aim of the present review was to highlight the vital factors of periodontal flaps associated with blood clot stability.HighlightThe data on periodontal regeneration and wound healing have evolved greatly in light of several factors, including space for blood clots and blood clot stabilization. In periodontal osseous defects, the stability of blood clots seems critical to wound healing. If mechanical forces can be managed by wound stabilization, the gingival flap-tooth root interface may show connective tissue repair. However, compromised adhesion is susceptible to mechanical forces and can cause wound breakage and epithelialization.ConclusionThe presence of a thick blood clot may hinder the plasmatic circulation between the recipient bed and graft during the initial stage of healing, which is critical in cases of mucogingival surgery. Root conditioning can also determine the healing consequence by enhancing blood clot adhesion.     

Periodontal tissue regeneration by recombinant human collagen peptide granules applied with β-tricalcium phosphate fine particles

ObjectivesRecombinant human collagen peptide (RCP) is a recombinantly created xeno-free biomaterial enriched in arginine-glycine-aspartic acid sequences with good processability whose use for regenerative medicine applications is under investigation. The biocompatibility and osteogenic ability of RCP granules combined with β-tricalcium phosphate (TCP) submicron particles (β-TCP/RCP) were recently demonstrated. In the present study, β-TCP/RCP was implanted into experimental periodontal tissue defects created in beagles to investigate its regenerative effects.MethodsAn RCP solution was lyophilized, granulated, and thermally cross-linked into particles approximately 1 mm in diameter. β-TCP dispersion (1 wt%; 500 μL) was added to 100 mg of RCP granules to form β-TCP/RCP. A three-walled intrabony defect (5 mm × 3 mm × 4 mm) was created on the mesial side of the mandibular first molar and filled with β-TCP/RCP.ResultsA micro-computed tomography image analysis performed at 8 weeks postoperative showed a significantly greater amount of new bone after β-TCP/RCP grafting (2.2-fold, P < 0.05) than after no grafting. Histological findings showed that the transplanted β-TCP/RCP induced active bone-like tissue formation including tartaric acid-resistant acid phosphatase– and OCN-positive cells as well as bioabsorbability. Ankylosis did not occur, and periostin-positive periodontal ligament-like tissue formation was observed. Histological measurements performed at 8 weeks postoperative revealed that β-TCP/RCP implantation formed 1.7-fold more bone-like tissue and 2.1-fold more periodontal ligament-like tissue than the control condition and significantly suppressed gingival recession and epithelial downgrowth (P < 0.05).Conclusionsβ-TCP/RCP implantation promoted bone-like and periodontal ligament–like tissue formation, suggesting its efficacy as a periodontal tissue regenerative material.     

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⁺.     

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.     

Amixicile depletes the ex vivo periodontal microbiome of anaerobic bacteria

ObjectivesAlthough periodontal diseases result from overgrowth of anaerobic bacteria, the effect of a specific knockdown of anaerobes on the disease outcome has yet to be examined. We have reported that amixicile, a non-toxic, readily bioavailable, and novel antimicrobial, specifically targets selected oral anaerobes through inhibition of the activity of pyruvate ferredoxin oxidoreductase (PFOR), a major enzyme mediating oxidative decarboxylation of pyruvate.MethodsHere, we generated an ex vivo microbiome derived from gingival pockets of human subjects with chronic periodontal disease and evaluated the efficacy of amixicile in generating a specific knockdown of anaerobic bacteria present in the microbiome.ResultsOur bioinformatics analysis identified PFOR-like coding capacity in over 100 genomes available from the HOMD database. Many of those bacteria were present in our ex vivo microbiome. Significantly, the anaerobic pathogens relying on PFOR for energy generation were specifically reduced in abundance following treatment with amixicile while non-PFOR bacteria were spared. Specifically, Prevotella, Veillonella, Slackia, Porphyromonas, Treponema, Megasphera, and Atobium were reduced in abundance. Such treatment resulted in the conversion of a microbiome resembling a microbiome derived from sites with periodontal disease to one resembling a microbiome present at healthy sites. We also compared the inhibitory spectrum of amixicile to that of metronidazole and showed that the antibiotics have a similar inhibitory spectrum.ConclusionsThis work further demonstrates that amixicile has the potential to reverse and prevent the outgrowth of anaerobic pathogens observed in subjects with periodontal disease.     

Effect of the duration of a conditioned stimulus on component recognition in binary taste mixtures in rats

ObjectivesThe aim of this behavioral study was to investigate the duration of a conditioned stimulus (CS-duration) necessary for rats to recognize the components of a binary taste mixture in a conditioned taste aversion (CTA) paradigm as well as the relationship between CS-duration and their spontaneous recovery.MethodsThe experimental rats were categorized under conditioned and control groups and further divided into three groups according to the CS-duration: 10, 30, and 60 s. As the test stimuli, a mixture of 100 mM sucrose (S) + 30 μM quinine hydrochloride (Q) and its components were used.ResultsOn day 1 of the CTA test, the number of licks (NL) for S + Q and S in all conditioned groups was significantly lower than that of the control group presented with CS for 60 s (CON-60), which was the representative control group determined by the initial CTA test. For Q, there was no significant difference between NL of the CTA group presented with CS for 10 s and that of CON-60; however, NL in the other two CTA groups, i.e., CTA-30 and CTA-60, was significantly lower than that of CON-60. When the rats were presented with a shorter CS-duration, they showed spontaneous recovery earlier depending on the CS-duration.ConclusionsThese results suggest that rats can recognize a binary taste mixture and its components using a CS-duration of more than 30 s and that spontaneous recovery from CTA learning depends on the CS- duration.