The role of fluoride in the preventive management of dentin hypersensitivity and root caries

Cerium- and samarium-nitrate interaction and accumulation on human dentin

OBJECTIVE

To investigate the accumulation of cerium-nitrate and samarium-nitrate on dentin without or with smear-layer and to test their antibacterial activity.

DESIGN

24 dentin-enamel slices were cut from 24 extracted molars. 12 slices underwent smear-layer creation (320 grit, 200 g, 5 s), the other 12 smear-layer removal (20 % EDTA, 300 s). Slices were halved to 48 semilunar-shaped specimens. One specimen per tooth was treated with either Ce(NO3)3 (50 wt% aqueous solution; pH = 1.29; n = 6) or Sm(NO3)3 (50 wt% aqueous solution; pH = 1.88; n = 6). The other specimen served as control (A. demin). After water rinsing, elemental composition (Ce, Sm, Ca, P, O, N, Na, Mg, C) was measured (EDX; EDAX Octane-Elect, APEX v2.5, low-vacuum) in dentin. Atomic percent (At%), Ca/P- and Ca/N-ratios were calculated and analyzed non-parametrically (α = 0.05, error rates method). Additionally, antibacterial activity (2 min exposure) of Ce(NO3)3 and Sm(NO3)3 against Streptococcus mutans, Actinomyces naeslundii, Schaalia odontolytica, and Enterococcus faecalis was determined (colony forming units) after anaerobic incubation at 37 °C for 24 h (control: 0.2 % CHX).

RESULTS

At% (median) of Ce and Sm were as follows: Ce(NO3)3 3.4 and 0.9 At%Ce with and without smear-layer, respectively; Sm(NO3)3 2.4 and 1.3 At%Sm with and without smear-layer, respectively. Ce(NO3)3 and Sm(NO3)3-application significantly decreased Ca/P-ratios (1.22 - 1.45; p ≤ 0.02) compared to controls (1.47 - 1.63). With smear-layer, significantly higher Ca/N-ratios (5.1 - 29.3) could be detected across all groups (p ≤ 0.004) compared to specimens without smear-layer (0.37 - 0.48). Ce(NO3)3 and Sm(NO3)3 showed reduction rates of up to ≥ 5 log10 steps for S. mutans, A. naeslundii, and S. odontolytica.

CONCLUSIONS

Cerium and samarium nitrate showed accumulation on dentin and certain antibacterial activity and could therefore be identified as potential compounds to treat and prevent dentin and root caries and dentin hypersensitivity.

Content analysis of fluoride-related posts on Instagram

BACKGROUND

The Internet and social media have become many people's primary sources of health information. Instagram is one of the most popular social media platforms, and users spend a significant amount of time daily on the platform. Therefore, analyzing oral health-related information shared online can help to identify the requirements of specific groups, assisting in the planning and execution of educational public health actions. As a result, this study was carried out to conduct a qualitative evaluation of fluoride-related content on Instagram in 2022-2023.

METHODS

Using hashtags associated with fluoride, a search was conducted on the Instagram application in the Persian language. All fluoride-containing posts were saved, and data was collected thrice at two-month intervals. MAXQDA software version 2020 was used to categorize the collected data content based on type, quality, and quantity.

RESULTS

The qualitative analysis included 1565 (9.45%) posts with fluoride-related content out of 16,475 total posts. After removing the duplicates, 400 posts remained, among which 282 posts (70.5%) and 118 posts (29.5%) were pro- and anti-fluoride, respectively. After qualitative analysis, 270 codes were examined and categorized into three main themes and eight subthemes: "fluoride sources," "The advantages and disadvantages of fluoride," and "Invalid beliefs about fluoride."

CONCLUSION

The frequency of pro-fluoride use was higher than anti-fluoride posts. However, due to the high prevalence of posts containing false information on fluoride toxicity for health, ineffectiveness on caries prevention, and conspiracy theories, there is a need to improve the quality of information on fluoride by providing scientific and unbiased explanations by professionals online or during dental visits and supervising social media content.

Clinical Investigation of Bioelectric Toothbrush for Dentin Hypersensitivity Management: A Randomized Double-Blind Study

BACKGROUND

The objective of this study was to evaluate how effectively the bioelectric toothbrush can alleviate dentin hypersensitivity (DHS) by using electrostatic forces to remove biofilm from the tooth surface.

METHODS

This study divided inpatients of a preventative dental clinic between March and October 2023 into the following two groups: a bioelectric toothbrush group (BET, n = 25) and a non-bioelectric toothbrush group (NBET, n = 18) as a control group. This was a randomized double-blind, placebo-controlled trial study. A survey, the number of hypersensitive teeth, the O'Leary index, the visual analogue scale (VAS), and the Schiff Cold Air Sensitivity Scale (SCASS) were also investigated.

RESULTS

When fluoride toothpaste was applied with a bioelectric toothbrush, the subjects' VAS and SCASS scores reflecting symptoms of hyperesthesia significantly decreased over time, as did the number of hypersensitive teeth and the O'Leary index. Moreover, the bioelectric toothbrush was confirmed to be effective in removing dental plaque.

CONCLUSIONS

Dental clinics must actively promote bioelectric toothbrushes and fluoride toothpaste for patients suffering from hyperesthesia and pain. Furthermore, these items can be suggested as preventative oral care products to patients with potential hyperesthesia.

Inhibitory effects of NaF on mitochondrial energy generation in human platelets in vitro

Background

fluoride is a beneficial ion that has been used in various fields, from industrial products to therapeutics. However, due to its narrow therapeutic index, fluoride sometimes acts as a toxic agent at relatively higher concentrations in the human body. Based on the interest in genetic stability, its cytotoxic effects have been investigated mainly in nucleated, adherent cells, such as fibroblasts. However, the sensitivity of blood cells, especially anucleate platelets, to fluoride is poorly understood. To fill this gap in the literature, we investigated the effects of relatively low levels of fluoride on platelet energy metabolism, function, and viability.

Methods

Platelet-rich plasma (PRP) was prepared from 15 non-smoking healthy male adults (age: 28-63) and treated with NaF (0.5 or 1.0 mM) in microtubes for up to 3 days. Platelet function was evaluated based on aggregation and adhesion activities. Platelet energy metabolism was evaluated based on intracellular ATP levels, extracellular lactate levels, and respiration activities. The mitochondrial membrane potential (Em) and localization of reactive oxygen species (ROS) were visualized using cytochemical methods. Platelet viability was evaluated by cell counting and tetrazolium reduction.

Result

NaF (1 mM) significantly reduced platelet viability and inhibited functions. Behind these phenomena, NaF substantially decreased mitochondrial Em and increased ROS production along with significant decreases in oxygen consumption and ATP levels. Simultaneously, NaF increased the lactate levels. Although not statistically significant, similar effects were observed at 0.5 mM NaF.

Conclusion

At relatively low levels, NaF has the potential to attenuate platelet function probably primarily through the inhibition of mitochondrial energy generation. Cytotoxicity may be directly related to ROS production. These findings suggest that when used topically, for example, for caries prevention in the oral cavity, NaF could interfere with wound healing and tissue regeneration by endogenous and exogenously added platelets in the form of PRP.

Dentin erosive wear is reduced by fluoride varnishes containing nanosized sodium trimetaphosphate in vitro

This study evaluated the effect of fluoride varnishes containing micrometric or nanosized sodium trimetaphosphate (TMP) on dentin erosive wear in vitro. Bovine root dentin blocks were selected by surface hardness and randomly divided into five experimental groups/varnishes (n = 20/group): placebo, 5% sodium fluoride (NaF); 5% NaF+5% micrometric TMP; 5% NaF+2.5% nanosized TMP; and 5% NaF+5% nanosized TMP. Half of the surface of all blocks received a single application of the assigned varnish, with subsequent immersion in artificial saliva for 6 h. Varnishes were then removed and the blocks were immersed in citric acid (90 s, 4×/day, 5 days). After each erosive cycle, ten blocks of each group were immersed in a placebo dentifrice for 15 s (ERO), while the other ten blocks were subjected to abrasion by brushing (ERO+ABR). Dentin erosive wear was assessed by profilometry. Data were submitted to 2-way ANOVA and to the Holm-Sidak test (p<0.05). Dentin erosive wear was significantly higher for ERO+ABR than for ERO for all varnishes. TMP-containing varnishes promoted superior effects against dentin erosive wear compared with 5% NaF alone; and 5% nanosized TMP led to the lowest wear among all varnishes. In conclusion, the addition of TMP to conventional fluoride varnish (i.e., varnish containing only NaF) enhanced its protective effects against bovine root dentin erosion and erosion+abrasion. Additionally, the use of 5% nanosized TMP led to superior effects in comparison to 5% micrometric TMP, both for erosion and erosion+abrasion in vitro.

Factors Influencing Tooth Sensitivity: Insights From the Hospital Universiti Sains Malaysia Using Bootstrap-Enhanced Ordinal Regression

Introduction Tooth sensitivity, or dentin hypersensitivity (DH), is characterized by sharp, sudden pain in response to stimuli such as cold, heat, sweet, or acidic foods and drinks. In Malaysia, there is limited understanding of the epidemiological aspects of tooth sensitivity, necessitating focused research. The condition results from the exposure of dentinal tubules transmitting stimuli to nerves within the pulp, with contributing factors including gingival recession, enamel erosion, and periodontal disease. This study aims to investigate the factors associated with tooth sensitivity among patients at the Hospital Universiti Sains Malaysia (USM) using advanced statistical methods. Methods This study employed a computational research design to develop an ordinal regression and bootstrap methodology using the RStudio software (Posit PBC, Boston, MA) to analyze secondary data from the Hospital Universiti Sains Malaysia. Six variables were analyzed: tooth wear severity, patient's age, gender, smoking status, alcohol status, and type of toothbrush. The study was conducted in three phases: 1) the development of an ordinal regression model, 2) the development of algorithms for ordinal regression and bootstrap method, and 3) validation using tooth sensitivity data. Results The analysis revealed that the replication with 1000 samples provided the most precise estimates with small standard errors (SE) and consistently significant effects across variables. Tooth sensitivity was influenced by age, toothpaste type, toothbrush type, and brushing frequency. Conclusion The study highlights the importance of considering multiple variables such as age, toothpaste type, toothbrush type, and brushing frequency in understanding tooth sensitivity. The combined ordinal regression and bootstrap technique significantly improved the model's accuracy, providing valuable insights for dental health professionals. These findings underscore the need for specific guidelines on oral hygiene practices to manage and reduce the risk of tooth sensitivity.

Influence of Er:YAG and ND:YAG laser irradiation and fluoride application on surface roughness and dentin surface wear after erosive challenge - An in vitro study

Background

To evaluate the effectiveness of Er:YAG and Nd:YAG laser on dentin hypersensitivity prevention, associated or not to acidulated phosphate fluoride (APF) after erosive challenge.

Material and Methods

104 specimens were obtained from bovine dentine and divided into groups (n=13): G1: Er:YAG; G2: Er:YAG followed by application of APF; G3: application of APF followed by Er:YAG, simultaneously; G4: Nd:YAG; G5: Nd:YAG followed by application of APF; G6: application of APF followed by Nd:YAG, simultaneously; G7:application of APF; G8: untreated. The parameters for Er:YAG were:10s, distance of 4mm, water cooling flow of 2mL/min, 2Hz, 3.92J/cm2. For the Nd:YAG: 10s, distance of 1mm, without cooling, 10Hz, 70.7J/cm2. The erosive drink was a cola at 4°C, 3×/day for 1 minute, for 5 days. Roughness and wear analysis were done in confocal laser microscope. Data were statistically analyzed (α=0.05).

Results

As regards roughness, there was no statistically difference among the groups. The groups irradiated with Er:YAG had a volume loss lower. G6 showed higher values than the groups irradiated with Er:YAG and lower than the other groups. The other groups irradiated with Nd:YAG showed similar wear results to the control.

Conclusions

The Er:YAG laser showed the lowest volume loss from wear analysis, suggesting the increased the acid resistance of dentin. Key words:Dentine sensitivity, Lasers, Sodium fluoride.

Synthesis and characterization of hydroxyapatite nanoparticles and their effects on remineralization of demineralized enamel in the presence of Er,Cr: YSGG laser irradiation

BACKGROUND

This study aims to synthesize and characterize hydroxyapatite nanoparticles (nano-HA) and evaluate their effects on the remineralization of demineralized enamel in the presence to Er,CR: YSGG laser irradiation.

MATERIALS AND METHODS

Enamel specimens from 44 human molars were divided into four groups: control, demineralized enamel, demineralized enamel treated with nano-HA, and demineralized enamel treated with nano-HA followed by Er,Cr:YSGG laser irradiation (0.5, 20 Hz, 60 µs, 20 s). Vickers microhardness test was used to evaluate the enamel surface hardness. The morphology and chemistry of enamel surfaces were assessed using scanning electron microscopy (SEM) and Raman spectroscopy, respectively.

RESULT

The result of this study showed that the application of Er,CR: YSGG laser irradiation to demineralized enamel treated with nano-HA had the highest impact on its microhardness.

CONCLUSION

ER,CR: YSGG laser irradiation promotes enamel remineralization after treatment with nano HA.

The Effects of a Novel Nanohydroxyapatite Gel and Er: YAG Laser Treatment on Dentin Hypersensitivity

PURPOSE

This study evaluates the effects of a novel nanohydroxyapatite gel and Er: YAG laser on the surface roughness, surface morphology, and elemental content after dentin hypersensitivity treatments.

METHODS

Dentin discs (2 × 3 × 3 mm3) were prepared from 75 human molars. Out of 75 human molars, 50 were used to evaluate surface roughness and randomly divided into five groups: Group ID (intact dentin), Group DD (demineralized dentin), Group BF (fluoride varnish/Bifluorid 10), Group Lsr (Er: YAG laser-50 mJ, 0.50 W, 10 Hz), and Group NHA (nanohydroxyapatite-containing gel). Dentin hypersensitivity was stimulated by 35% phosphoric acid for 1 min (except Group ID). The surface roughness (Ra, μm) was measured via contact profilometry (n = 10). Out of the 75 sound human molars, 25 were used to evaluate the surface morphology and elemental content using scanning electron microscopy and energy-dispersive X-ray spectroscopy (n = 5). The data were statistically analyzed using Welsch ANOVA, Games-Howell, Kruskal-Wallis, and Dunn tests (p < 0.05).

RESULTS

Group Lsr showed significantly lower surface roughness than Group NHA and Group BF (p < 0.05). The SEM analysis indicated that most of the dentinal tubules were obliterated for Group NHA. Precipitant plugs with partially occluded dentinal tubules were observed for Group BF, while partially or completely occluded tubules with a melting appearance were detected for Group Lsr. The EDS analysis revealed that Group NHA and Group Lsr presented similar calcium and phosphorus amounts to Group ID. All dentin hypersensitivity treatment methods could provide promising results in terms of tubular occlusion efficiency. However, laser treatment resulted in smoother surfaces, which could help prevent dental plaque accumulation.

Penetration and durability of CPP-ACP paste and sodium fluoride varnish as desensitizing agents: An in vitro comparison

Background

This study aimed to investigate and compare the penetration and durability of two dentin desensitizers, sodium fluoride varnish and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste, using electron microscopy.

Methods

The study was performed on 60 dentin specimens prepared from extracted human premolars. After applying 17% EDTA to remove the smear layer, the specimens were divided into two groups. MI Paste and Bi-fluoride varnish were applied to the specimens. Microscopic images of 20 samples were obtained immediately. Twenty other samples were accessed after 15 days, and the other 20 were accessed after 30 days of toothbrushing and thermal cycling. Both surface and longitudinal cross-sectional images (after sample fracture) were studied. Data were analyzed with two-way ANOVA and Mann-Whitney U test at a significance level of P<0.05.

Results

The mean depth of material penetration was significantly time-dependent and fluctuated in both groups. There was a significant difference between the mean level of plugs between 0, 15, and 30 days (P<0.001). Penetration increased with time for the MI Paste group, while in the Bi-fluoride group, the increase was significant at 15 and 30 days than immediately after application. The mean thickness of the plugs was significantly different at the three time periods, and MI Paste showed a sudden decrease in plug thickness after 15 days.

Conclusion

Immediately after application, Bi-fluoride occluded dentinal tubules more effectively, and its durability after abrasion and thermal fatigue were higher than MI Paste.

Antigingivitis, Desensitizing, and Antiplaque Effects of Alkaline Toothpastes: A Randomized Clinical Trial

Gingivitis is a widespread disease commonly associated with dentin hypersensitivity, that, in turn, may complicate routine dental care, leading to plaque accumulation. We aimed to assess the antigingivitis, desensitizing, and antiplaque effects of a fluoride-containing (TWF) alkaline toothpaste and a fluoride-free (TW) alkaline toothpaste. Eighty-four consenting patients aged 20-25 years with diagnosed gingivitis and dentin hypersensitivity (DH) were recruited in this double-blind, parallel-group study and randomly divided into two groups (each n = 42). Eighty-two patients completed the entire study protocol. The outcomes were assessed after 4 weeks of intervention. A significant improvement in gingival condition was found according to the modified gingival index, with effect sizes of 0.99 [CI95%: 0.52-1.46] and 1.71 [CI95%: 1.18-2.24], and the gingival bleeding index, with effect sizes of 3.17 [CI95%: 2.39-3.94] and 2.64 [CI95%: 1.96-3.32] in the TW and TWF groups, respectively. DH also decreased in both groups, with a significantly greater reduction in the TWF group (effect sizes of 3.28 [CI95%: 2.51-4.04] and 3.10 [CI95%: 2.40-3.80] according to the visual analog scale and Schiff scale, respectively). No side effects were registered. In conclusion, the use of alkaline toothpaste provided a significant reduction in gingival inflammation and bleeding, DH, and oral hygiene after 4 weeks of daily use in young adults. Trial Registration: NCT0562376. Funding: none.

Fast Construction of Biomimetic Organic-Inorganic Interface by Crosslinking of Calcium Phosphate Oligomers: A Strategy for Instant Regeneration of Hard Tissue

The organic-inorganic structure in biological hard tissues ensures their marvelous characteristics but these hybrids are easily destroyed by the demineralization of inorganic components, e.g., the damage of dentin. Current clinical materials for hard tissue regeneration commonly act as "fillers" and their therapeutic effect is limited by the failures of biological-linked organic-inorganic interface reconstruction. Herein, a fast in situ crosslinking of calcium phosphate oligomers (CPOs) on collagen matrixes for efficient organic-inorganic interface re-construction, which can result in a biomimetic hybrid, is demonstrated. By using damaged dentin as an example, the inorganic ionic crosslinking can instantly infiltrate into the dentin matrix to rebuild a dense and continuous calcium phosphate-collagen hybrid within only 5 min, where the structurally integrated organic-inorganic interface is identical to natural dentin. As a result, the damaged dentin can be fully recovered to a healthy one, which is superior to any current dentin treatments. The fast construction of biomimetic hybrid by inorganic ionic crosslinking provides a promising strategy for hard tissue repair and follows great potentials of CPOs as advanced biomedical materials in future.

Development of Root Caries Prevention by Nano-Hydroxyapatite Coating and Improvement of Dentin Acid Resistance

There is no established method for optimizing the use of dentin to prevent root caries, which are increasing in the elderly population. This study aimed to develop a new approach for root caries prevention by focusing on bioapatite (BioHap), a new biomaterial, combined with fluoride. Bovine dentin was used as a sample, and an acid challenge was performed in three groups: no fluoride (control group), acidulated phosphate fluoride treatment (APF group), and BioHap + APF treatment (BioHap group). After applying the new compound, the acid resistance of dentin was compared with that of APF alone. The BioHap group had fewer defects and an increased surface hardness than the APF group. The BioHap group had the smallest lesion depth and least mineral loss among all groups. Using a scanning electron microscope in the BioHap group showed the closure of dentinal tubules and a coating on the surface. The BioHap group maintained a coating and had higher acid resistance than the APF group. The coating prevents acid penetration, and the small particle size of BioHap and its excellent reactivity with fluoride are thought to have contributed to the improvement of acid resistance in dentin. Topical fluoride application using BioHap protects against root caries.

Inhibition of Demineralization of Dentin by Fluoride-Containing Hydrogel Desensitizers: An In Vitro Study

Several desensitizers routinely used clinically for dentin hypersensitivity are expected to inhibit demineralization. This study aimed to evaluate the effectiveness of sealing materials in inhibiting demineralization and increasing fluorine (F) uptake by acid-treated root surfaces. Five noncarious extracted human teeth were used to produce specimens. Three different fluoride-containing materials, namely "MS Coat F" (MS), "MS Coat Hys Block Gel" (HS), and CTX2 Varnish (FV), were used herein. Each material was applied to the demineralized root surface. Single sections were obtained from each specimen. All surfaces of each specimen, except the polished surface, were covered with wax and immersed in an automatic pH cycling system for 2 weeks. Fluorine and calcium distributions in the carious lesions of each specimen were evaluated using proton-induced gamma emission (PIGE) and X-ray (PIXE) techniques, respectively. Dentin demineralization was analyzed using transverse microradiography (TMR) before and after pH cycling. µPIXE/PIGE analysis demonstrated that all sample groups showed increased fluoride uptake on the root surface. TMR analysis revealed that both HS and FV showed significantly lower integrated mineral loss values than the control group. All three samples demonstrated a tendency towards increased fluoride uptake from fluoride-containing hypersensitivity desensitizers and a demineralization inhibition effect on root dentin.

Remineralization of Artificially Demineralized Human Enamel and Dentin Samples by Zinc-Carbonate Hydroxyapatite Nanocrystals

(1) Background: Decalcified enamel and dentin surfaces can be regenerated with non-fluoride-containing biomimetic systems. This study aimed to investigate the effect of a zinc carbonate-hydroxyapatite-containing dentifrice on artificially demineralized enamel and dentin surfaces. (2) Methods: Human enamel and dentin discs were prepared and subjected to surface demineralization with 30% orthophosphoric acid for 60 s. Subsequently, in the test group (n = 20), the discs were treated three times a day for 3 min with a zinc carbonate-hydroxyapatite-containing toothpaste (biorepair^®). Afterwards, all samples were gently rinsed with PBS (5 s) and stored in artificial saliva until next use. Samples from the control group (n = 20) received no dentifrice-treatment and were stored in artificial saliva, exclusively. After 15 days of daily treatment, specimens were subjected to Raman spectroscopy, energy-dispersive X-ray micro-analysis (EDX), white-light interferometry, and profilometry. (3) Results: Raman spectroscopy and white-light interferometry revealed no significant differences compared to the untreated controls. EDX analysis showed calcium phosphate and silicon dioxide precipitations on treated dentin samples. In addition, treated dentin surfaces showed significant reduced roughness values. (4) Conclusions: Treatment with biorepair^® did not affect enamel surfaces as proposed. Minor mineral precipitation and a reduction in surface roughness were detected among dentin surfaces only.

Xylitol Fluoride Varnish: In Vitro Effect Analysis on Enamel by Atomic Force Microscopy

(1) Background: Numerous studies have shown the beneficial role of fluoride in the primary prevention of dental caries. The aim of the present study was to put into evidence the change in the enamel structure immediately after the application of a fluoride varnish. (2) Methods: A xylitol−fluoride varnish was evaluated. The enamel specimens (n = 10) were analyzed by atomic force microscopy on enamel surface and treatment with fluoride varnish applied. The dimensional topographic analysis was performed by 2D and 3D analysis software. Statistical analysis was performed using SPSS Version 26.00 (IBM, Armonk, NY, USA). A one-sample statistics test was used to identify significant differences (p < 0.05). (3) Results: Surface roughness (Ra) measurements ranged from Ra = 0.039 μm (±0.048), to Ra = 0.049 μm (±0.031), respectively (p < 0.05), with an increase in the surface roughness passing from the intact enamel to the enamel exposed to fluoride varnish. When comparing Ra values of the nonfluorinated enamel and fluorinated enamel, significant differences (p < 0.05) were found, suggesting that the varnish had a protective effect on the enamel surface. (4) Conclusions: Xylitol−fluoride varnish, even in one single short-time application, is effective in reducing the surface roughness of enamel structure exposed to abrasion, thus increasing resistance to dental caries.

Functional role of inorganic trace elements in dentin apatite tissue-part III: Se, F, Ag, and B

Dentin hydroxyapatite possesses a unique versatile structure which allows it to undergo ionic substitutions. Trace elements play pivotal roles within the oral cavity, especially in dentin apatite tissue. Therefore, it is critical to explore the role of these elements in dentin apatite structure. The roles of other inorganic elements in dentin apatite were discussed in part I (Mg, Sr, Zn, and Fe) and part II (Cu, Mn, Si, and Li) of these series. In the last part of the review series, the role of selenium, fluorine, silver, and boron in the regulation of dentin apatite structure and function was discussed. We evaluated how these elements affect the overall size, morphology, and crystallinity of dentin apatite crystals. Moreover, we investigated the importance of these elements in regulating the solubility of dentin apatite. An electronic search was performed on the role of these trace elements in dentin apatite from January 2010 to January 2022. The concentration of selenium in teeth has been explored only recently, particularly its incorporation into dentin apatite. Silver nanomaterials inhibit the growth of cariogenic microorganisms as well as arrest the degradation of collagen. Fluorine was found to have important roles in dentin remineralization and dentinal tubule occlusion, making it widely used for hydroxyapatite doping. Boron is critical for mineralized tissues like bone, dentin, and enamel, but its exact role in dentin apatite is unknown. Therefore, understanding the impact of these elements on dentin apatite is potentially transformative, as it may help to fill a significant knowledge gap in teeth mechanics.

Advances in the Management of Dentin Hypersensitivity: An Updated Review

Background:

Objective: The objective of this narrative review is to present an overview of dentin hypersensitivity and of the prevalence, etiology, mechanism, diagnosis, and clinical management.

Methods:

Available articles (research, reviews, commentary, views, or editorial) on hypersensitivity were searched and reviewed from January 1990 till March 2021 in Pubmed, Scopus, Google Scholar, and Science Direct. Relevant studies in English were included and critically analyzed in this article.

Results:

Dentin hypersensitivity causes severe pain. The most effective and least invasive remedy is using desensitizing toothpaste. In addition, based on the dentin hypersensitivity severity, management can be done professionally in-office and through self-applied at-home treatments.

Conclusion:

Although dentin hypersensitivity causes severe pain, it can be treated using a proper remedy. Correct diagnosis helps in the proper management of dentine hypersensitivity.

Management of dentinal hypersensitivity should be done with more conservative strategies first, followed by irreversible dental interventions.

Effectiveness of Two Different Fluoride-Based Agents in the Treatment of Dentin Hypersensitivity: A Prospective Clinical Trial

Hyperesthesia is related to increased sensitivity of dental tissues to mechanical, chemical and thermal stimuli. The aim of this prospective clinical trial was to compare the effectiveness of a calcium-fluoride-forming agent (Tiefenfluorid®, Humanchemie GmbH, Alfeld, Germany) with that of a fluoride varnish (EnamelastTM, Ultradent Inc., Cologne, Germany) in the treatment of dental hyperesthesia in adult patients. In total, 176 individuals (106 females and 70 males, aged 18-59 years old) diagnosed with dental hyperesthesia (DH) were enrolled. The main clinical symptoms were hyperesthesia from coldness and sweetness during chewing; the types of clinical lesions were also determined and recorded. The patients were selected randomly and divided into two groups: (i) the first group of 96 patients was treated with Tiefenfluorid® applied in three appointments at 7-day intervals; (ii) the second group of 80 patients was treated with EnamelastTM, applied seven times at 7-day intervals. All the patients were recalled 7 days, 14 days, 1 month, 3 months, and 6 months from the last application. At the baseline and during every follow-up visit, the DH was measured with a pulp tester. A random intercept/random slope model was used to evaluate the effect of the treatment, at various times with respect to the initial diagnosis. Within the limits of the present study, Tiefenfluorid® was more effective than EnamelastTM against DH in that it provided long-lasting results, with a significant improvement still detected at the latest 6-month follow-up.

3D Printed In Vitro Dentin Model to Investigate Occlusive Agents against Tooth Sensitivity

Tooth sensitivity is a painful and very common problem. Often stimulated by consuming hot, cold, sweet, or acidic foods, it is associated with exposed dentin microtubules that are open to dental pulp. One common treatment for tooth hypersensitivity is the application of occlusive particles to block dentin microtubules. The primary methodology currently used to test the penetration and occlusion of particles into dentin pores relies upon dentin discs cut from extracted bovine/human teeth. However, this method is limited due to low accessibility to the raw material. Thus, there is a need for an in vitro dentin model to characterize the effectiveness of occlusive agents. Three-dimensional printing technologies have emerged that make the printing of dentin-like structures possible. This study sought to develop and print a biomaterial ink that mimicked the natural composition and structure of dentin tubules. A formulation of type I collagen (Col), nanocrystalline hydroxyapatite (HAp), and alginate (Alg) was found to be suitable for the 3D printing of scaffolds. The performance of the 3D printed dentin model was compared to the natural dentin disk by image analysis via scanning electron microscopy (SEM), both pre- and post-treatment with occlusive microparticles, to evaluate the degree of dentinal tubule occlusion. The cytocompatibility of printed scaffolds was also confirmed in vitro. This is a promising biomaterial system for the 3D printing of dentin mimics.

The effect of layered double hydroxide on fluoride release and recharge from a commercial and an experimental resin varnish

OBJECTIVES

Layered Double Hydroxide (LDH) is capable of fluoride anion exchange and release. This study investigated the effects of incorporating ZnAl-LDH in commercial and experimental dental varnishes, on fluoride release and re-release after charging in NaF.

METHODS

Five discs of each material (commercial ClinproXT varnish and experimental light cured resin varnish), with and without 9%ZnAl-LDH were immersed and agitated in deionised water (DW) at 37 °C. A fluoride ion selective electrode measured fluoride release in DW daily over two-weeks. At 3, 6, 9 and 12 days the discs were recharged in 15 ml 0.05 M NaF solution (37 °C) for five minutes followed by immersion in DW. Energy dispersive X-ray spectra (EDS), weight changes and SEMs were performed on discs, before and after each cycle.

RESULTS

Evidence of ZnAl-LDH was confirmed by the presence of peaks for zinc and aluminium in EDS spectra. Cumulative fluoride and mean fluoride released between Clinpro, Clinpro + LDH and resin were significantly different (ANOVA, Tukey's HSD post-hoc test, p < 0.001) except between the resin and resin + LDH. Mean fluoride concentrations differed significantly after every recharge between Clinpro, Clinpro + LDH and resin, but not between the resin and resin + LDH (p < 0.01). The weights and SEMs of the experimental resins +/-LDH, appeared to be stable whilst the weights of Clinpro samples +/-LDH, fluctuated and fragmented.

SIGNIFICANCE

ClinproXT and experimental resin containing ZnAl-LDH recharged with fluoride did not significantly increase fluoride release compared to the unmodified materials. However, all LDH-F incorporated materials demonstrated fluoride recharging properties which appear beneficial to dentistry and thus further work is required to improve these properties.

Fluoride-Releasing Self-Etch Adhesives Create Thick ABRZ at the Interface

A fluoride-releasing adhesive system is expected to promote mineralization of demineralized dentin/enamel around a composite restoration, thereby contributing to the longevity of the restoration. Scanning electron microscopic (SEM) and transmission electron microscopic (TEM) observations revealed the formation of an “acid–base resistant zone” (ABRZ) beneath the hybrid layer when dentin was treated with a self-etch adhesive system. A thicker ABRZ was formed from the upper slope to the end of the outer lesion, indicating greater resistance against an acid-base challenge, when a fluoride-releasing self-etch adhesive system was used. The slope formation of a fluoride-releasing adhesive is believed to be due to fluoride-release from the adhesive. Quantitative assessment of the acid resistance was performed at the interface using the region of interest (ROI) mode of a digital image analysis software package. The area of the ABRZ is influenced by the concentration of fluoride release from the adhesive resin. The threshold of fluoride concentration in the adhesive may exist to influence the morphology of the ABRZ. X-ray absorption fine structure (XAFS) analysis of the dentin treated with different concentrations of NaF-mouth rinses suggested that different fluoride concentrations result in the formation of different chemical compounds, such as fluorapatite and CaF₂-like structures, on the dentin surface. This may explain the differences in μTBS values and morphological appearance of the ABRZ. NaF is effective in enhancing the enamel/dentin bond durability and also helps create a high quality of ARBZ to improve the clinical success of restorations.

The Potential of Hydroxyapatite Toothpaste to Prevent Root Caries: A pH-Cycling Study

PURPOSE

The effectiveness of a hydroxyapatite (HAP) toothpaste and a fluoride toothpaste in preventing root tissue demineralization (root caries) was compared using an established pH-cycling caries model.

MATERIALS AND METHODS

Sixty dentin blocks were produced from the root tissue of extracted human teeth and were assigned to 3 test groups (n=20/group): 10% hydroxyapatite toothpaste (HAP), 1450 ppm fluoride toothpaste (fluoride), and artificial saliva (artsaliva). Early root caries lesions were developed in each sample by 7-day demineralization using a pH-cycling caries model. The daily cyclic treatment regimen consists of two 2-minute toothpaste-slurry treatment periods, one 6-hour acid challenge using acidified gel (pH 4.5), and then storage in remineralizing solution (artsaliva) for the rest of the time. Demineralization was assessed as the amount of mineral loss (∆z) using transverse microradiography (TMR). Pairwise comparisons (between treatments) were performed using analysis of variance (ANOVA), and then Tukey's HSD for multiple comparisons. All p-values are considered significant if p<0.05.

RESULTS

Both ANOVA and Tukey's HSD indicated no significant (ANOVA; n=20) difference in mean ∆z among the groups, with least ∆z (±Sd) in the HAP (1117±366) compared to fluoride (1392±334) and artsaliva (1406±223). Relative to control, HAP and fluoride inhibited root demineralization by 21% and 6%, respectively.

CONCLUSION

Within the limit of the present study, the tested toothpaste containing 10% HAP is an effective root caries control toothpaste. Toothpaste containing 10% HAP was slightly more effective in preventing tooth demineralization than 1450 ppm fluoride provided as sodium fluoride. Thus, this study shows that HAP toothpastes can serve as an effective alternative to fluoride toothpastes for root caries management.

In situ evaluation of desensitizing toothpastes for protecting against erosive tooth wear and its characterization

OBJECTIVE

This five-phase, single-blind, crossover in situ trial evaluated the effects of desensitizing or anti-erosive toothpastes on dentin erosive wear and tubule occlusion.

MATERIALS AND METHODS

Some characteristics such as relative dentin abrasivity (RDA), viscosity (V), cytotoxicity, and fluoride and calcium (Ca) availability of the toothpastes were also tested. Samples were positioned on removable intraoral appliances from 15 volunteers (n=4), according to the groups, C-control (0 ppm fluoride), F-sodium monofluorophosphate (MFP), A-MFP and arginine+calcium carbonate, CSP-calcium sodium phosphosilicate, and CS-MFP and calcium silicate+sodium phosphate. Erosion-abrasion cycling was performed (1% citric acid, 2min, 6×/day; toothbrushing, 5s, 2×/day). Surface loss (SL) was evaluated by optical profilometry. Environmental scanning electron microscopy images (ESEM) counted the number of open dentin tubules (ODTs). Data were statistically analyzed (α=0.05).

RESULTS

There were no significant differences in SL among groups (p=0.468). The ODT for CSP, CS, and A groups were significantly lower than the control. CSP and CS presented significantly less ODT than F, but they did not significantly differ from A. F and CS were more abrasive than all the other toothpastes; CSP was more abrasive than A, and C was the least abrasive. CSP presented higher V (p<0.05). All toothpastes presented lower cell viability than the control without toothpaste exposure. F and A presented significantly higher values of F^- (p<0.05). All fluoride toothpastes had similar amount of Ca, differing from the control (p<0.05).

CONCLUSION

Although the toothpastes caused similar degree of erosive wear, CSP and CS were able to occlude the dentin tubules.

CLINICAL RELEVANCE

Desensitizing toothpastes containing calcium, sodium, phosphate, and silicate could be a suitable option for treating dentin hypersensitivity.

Low level laser therapy, Er,Cr:YSGG laser and fluoride varnish for treatment of dentin hypersensitivity after periodontal surgery: A randomized clinical trial

This clinical trial aimed to compare the effects of low-level laser therapy (LLLT), Er,Cr;YSGG laser, and fluoride varnish, as compared to the placebo laser on decreasing dentin hypersensitivity (DH). This randomized, double-blinded clinical trial included 60 jaw quadrants in 24 patients who underwent periodontal surgery. The quadrants were randomly assigned to 4 groups and received treatments as follows. Group 1: LLLT with a combination of red and infrared wavelengths, group 2: Er,Cr:YSGG laser (0.25 W and 0.5 W), group 3: fluoride varnish, and group 4: placebo laser. The sensitivity response to the cold spray was recorded using visual analogue scale (VAS) at baseline, immediately, and 1 week post-treatment. The data were analyzed by repeated measures analysis at the significance level of P<0.05. There was a significant reduction in DH after treatment by low-level lasers, Er,Cr:YSGG laser, or fluoride varnish compared to the baseline data (P<0.05), but the placebo group displayed no significant alteration in DH (P=0.069). At 1 week, the VAS score in the Er,Cr:YSGG laser group was significantly lower than that of the LLLT (P= 0.043) and placebo (P<0.001) groups. Furthermore, the subjects who received fluoride varnish exhibited significantly lower DH compared with the placebo group (P = 0.023). Er,Cr:YSGG laser was the most effective strategy in dealing with DH, as it caused the greatest pain reduction over the study period and showed a significant superiority over LLLT and placebo groups. Alternatively, the application of fluoride varnish could be recommended for attenuating DH following periodontal surgery.

Oral care product formulations, properties and challenges

This review explores the physical, chemical and structural properties of key components of oral care products, whilst looking at the challenges which need to be overcome to continue to improve the efficacy of oral care, and improve dental health. Oral care has been an essential part of all populations and cultures around the world for thousands of years. To maintain good oral health, dental plaque causing bacteria and malodour must be controlled whilst also strengthening and protecting the teeth to prevent dental caries. Advanced modern formulations need to provide controlled and extended release of ingredients vital for dental health. With modern day products such as toothpastes and mouthwashes, it has never been easier to maintain good oral hygiene and health, yet the incidence of dental caries is still on the rise. The complex formulations of modern toothpastes and mouthwashes makes them one of the most sophisticated pharmaceutical products on the market today. The demands of the consumer coupled with the complexity of the oral cavity make it one of the most challenging development processes.

Remineralising effects of fluoride varnishes containing calcium phosphate on artificial root caries lesions with adjunctive application of proanthocyanidin

OBJECTIVES

To evaluate the remineralising effects of fluoride (F) varnishes containing bioavailable calcium-phosphate compound (Ca-P) based remineralisation systems and 5000 ppm F toothpaste (FTP) on root caries lesions (RCLs) and the potential effects of proanthocyanidin (PA) for the treatments of RCLs when used as an adjunct to F regimens.

METHODS

Demineralised root dentine and a pH-cycling model were used to mimic RCLs and the oral environment. Remineralising effects of MI Varnish^TM (MIV) containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and Clinpro™ White Varnish (CPWV) containing tri-calcium phosphate (TCP) along with FTP and PA were evaluated regarding the birefringence, elemental composition, mechanical properties and mineral density of remineralised dentine with Duraphat^TM as a comparison.

RESULTS

MIV, CPWV and Duraphat^TM promoted the incorporation of F into RCLs and increased mineral density but did not change microhardness of root dentine significantly. Surface microhardness increased significantly when MIV or CPWV was used with 5000 ppm FTP. Application of PA with F regimens significantly increased subsurface mineral density. When PA was applied with MIV or CPWV along with FTP, the highest ion uptake and relative mineral gain (%ΔZ) was achieved, and significant increase of microhardness was up to 30 μm depth. Generally, MIV was associated with a higher mineral content gain than CPWV.

SIGNIFICANCE

Treatment of carious root surfaces remains challenging due to the complex pathological processes and difficulty in restoring the highly organised structure of root dentine. Treatment strategies targeting both remineralisation and preservation of the dentinal organic matrix have the potential to improve the fluoride-mediated remineralisation approaches.

Preventive effect of experimental polymer-based desensitizers with NaF on demineralization of root dentin -observed using micro-CT

This study compared the effect of experimental polymer-based desensitizers with NaF and oxalic acid (OA) for preventing root demineralization via observation using micro-CT. Bovine root dentin surfaces were treated with coating materials: no treatment; MS0(+) (MS Coat One^®); MS3000(+) (MS Coat^®); MS0(-); MS3000(-); MS7000(+/-); fluoride gel (NaF9000). MS; MS polymer, 0-7000; NaF concentrations, (+/-); OA. The specimens were scanned using micro-CT before and after demineralization (pH4.5, 10 h). Following this, the mean mineral loss (ML) after demineralization was calculated, and the specimens were observed under a scanning electron microscope (SEM). The ML values of MS3000(+), MS7000(-), MS7000(+) and NaF9000 were significantly lower than the other groups (p<0.05). Under an SEM, a membrane structure was observed to have formed on the dentin surface in the presence of the MS, fluoride, and OA. The experimental polymer-based desensitizer with oxalic acid and a high concentration of fluoride is effective for preventing root demineralization.

Can Desensitizing Toothpastes Also Have an Effect on Gingival Inflammation? A Double-Blind, Three-Treatment Crossover Clinical Trial

Background: Many desensitizing toothpastes exist commercially; however, few clinical trials have investigated their anti-inflammatory effects. This study aimed to evaluate the anti-inflammatory effect and patient appreciation of two toothpastes containing desensitizing agents: (1) a zinc-carbonate-hydroxyapatite nanoparticle (CHA) and (2) a calcium sodium phosphosilicate bioactive glass (CSPS). Methods: CHA and CSPS were compared with an anti-inflammatory and antibacterial herbal based toothpaste (HB). The aims were accomplished by comparing the following outcomes: (1) the reduction in plaque and bleeding score (Full Mouth Plaque Score (FMPS) and Full Mouth Bleeding Score (FMBS), respectively); (2) the antibacterial activity (AbA) of the toothpaste by saliva samples; (3) the patient appreciation score (Visual Analogue Scale; VAS). Clinical parameters were assessed at baseline and 14 days post-treatment. Results: The final sample consisted of 25 subjects, aged between 20 and 58 years. Although no differences in FMPS were reported (p > 0.05), both desensitizing toothpastes showed an improvement in FMBS. CSPS and HB recorded more AbA compared to CHA (p < 0.05). Moreover, HB resulted in a higher VAS score than both desensitizing toothpastes (p < 0.05). Conclusion: In conclusion, only CSPS displayed a similar anti-inflammatory effect compared to HB. Despite the low VAS score, CSPS could be considered as a valid and effective toothpaste in subjects with both dentin hypersensitivity and inflamed gums, highlighting its utility in clinical practice.

Oral Rehabilitation Using Noninvasive Restorative Approach for Late Mixed Dentition of Preterm Birth Child with Amelogenesis Imperfecta

Preterm birth children comprise about 6% of live births around the world. It is known that premature children exhibit oral anomalies that could affect the function and/or appearance of their dentition in addition to their medical needs. A diagnosis of amelogenesis imperfecta (AI) can present a challenge for both the patient and the treating clinician. This can be more complicated in the case of child treatment, where cooperation and some of the treatment modalities for adults can not be considered. Conventional management of such children is not possible due to the ongoing process of growth and development and the ability of the child to cope with the extensive and lengthy treatment procedure. This article highlights a minimally invasive method for managing AI using adhesive and full-coverage restoration that requires no tooth preparation; this allows the structural integrity of the teeth to be maintained, along with their vitality. As a result, the child will have teeth with better function and aesthetic, to improve eating, appearance, and self-confidence.

Shockwave application enhances the effect of dentin desensitizer

OBJECTIVES

The purpose of this study was to develop a new device that can improve the effect of desensitizer using shockwaves and to verify its efficacy.

METHODS

A micro-shockwave generator was developed using a piezoelectric actuator (PIA-1000, piezosystem jena GmbH, Jena, Germany), an Arduino Uno microcontroller (Arduino, Torino, Italy), and a high voltage pulser (HVP-1000, piezosystem jena GmbH) at 700 V (400 A) and 100 μs. The occlusal surfaces of 20 extracted human upper and lower third molars without caries or restoration were reduced to expose the occlusal dentin, and the prepared occlusal surfaces were acid-etched with 32% phosphoric acid to remove the smear layer. The tooth specimens were connected to a fluid flow measurement instrument (nanoFlow, IB SYSTEMS, Seoul, Korea), permeability through dentin via dentinal fluid flow (DFF) was measured for 300 s, and the average DFF rate (Baseline DFF rate) was calculated. A desensitizer (SuperSeal, Phoenix Dental, Fenton, MI, USA) was applied to the acid-etched occlusal dentin surface of 10 randomly selected tooth specimens, left for 10 s, and rubbed with a microbrush for 30 s (Group 1). For the remaining teeth, the desensitizer was applied, and a shockwave (100 μm stroke, 10,000 G) was applied for 10 s (2 shots/s) and rubbed with a microbrush for 30 s (Group 2). After desensitizer application, subsequent DFF was measured for 600 s, and the average DFF rate was calculated (post-application DFF rate). DFF was continuously measured in real-time at 25 ± 0.5 ℃ under a hydrostatic pressure of 25 cm. The percentage reduction in DFF rate after desensitizer application (with or without shockwave) was calculated with respect to baseline DFF rate. Data were analyzed with independent t-test (α = 0.05).

RESULTS

For all tooth specimens, DFF rate decreased after desensitizer application irrespective of the presence of shockwaves. The percentage reduction in DFF rate of SuperSeal with shockwave (Group 2) was 42.8 ± 19.0%, which was significantly higher than the 26.2 ± 13.6% of the SuperSeal only group (Group 1) (p < 0.05).

SIGNIFICANCE

Measurement of DFF change in real-time shows that shockwaves can help reduce dentin permeability beyond that SuperSeal dentin desensitizer produced alone.

Anti-demineralization characteristics of surface pre-reacted glass-ionomer (S-PRG) filler-containing varnishes

This study investigated the anti-demineralization effects of surface pre-reacted glass-ionomer (S-PRG) filler-containing varnishes. Thirty-five bovine root specimens were divided into five treatment groups, with seven specimens each coated with 1) MI varnish (MIV), 2) F varnish (FV), 3) PRG varnish I (PV), 4) PRG varnish II (with sodium fluoride added, PVF), and 5) acid-resistant nail varnish (Control). A 3×1 mm area of the dentin surface adjacent to each varnish was demineralized for one week at 37°C. Integrated mineral loss (IML) of these lesions was determined by transverse microradiography, as was the amount of fluoride released by each material. IML was significantly lower in the PV and PVF groups than in the Control group, and was significantly lower in the PVF than in the MIV and FV groups. These findings indicated that S-PRG filler-containing varnishes, especially varnish containing sodium fluoride, had superior anti-demineralization effects on root dentin.

Effects of microsurface structure of bioactive nanoparticles on dentinal tubules as a dentin desensitizer

In this in vitro study, spherical mesoporous bioactive glass nanoparticle (MBGN) and non-porous bioactive glass nanoparticle (BGN) were fabricated. The impact of mesopores on dentinal tubule occlusion and bioactivity was compared to examine the potential of these materials in alleviating dentine hypersensitivity (DH). MBGN, dense BGN were synthesized by sol-gel methods and characterized. Bioactivity and ion dissolution ability were analyzed. Twenty-four simulated sensitive dentin discs were prepared and randomly divided into three groups (n = 8 each); Group 1, no treatment; Group 2, Dense BGN; Group 3, MBGN. Then, four discs per group were treated with 6wt.% citric acid challenge to determine the acidic resistance. The effects on dentinal tubule occlusion were observed by FESEM. The microtensile bond strength (MTBS) was also measured. Cytotoxicity was examined using the MTT assay. According to the results, dense BGN without mesopore and MBGN with mesopore were successfully fabricated. Dense BGN and MBGN occluded the dentinal tubule before and after acid challenge. However, only MBGN formed a membrane-like layer and showed hydroxyapatite formation after soaking SBF solution. There were no significant differences in MTBS among dense BGN, MBGN (P>0.05). The cell viability was above 72% of both materials. The higher bioactivity of MBGN compared with that of dense BGN arises from the structural difference and it is anticipated to facilitate dentin remineralization by inducing hydroxyapatite deposition within the dentinal tubule.

Evaluation of diode laser along with 1.23% acidulated phosphate fluoride gel on dentinal tubule occlusion: An in vitro study

Context

Several studies have recommended the use of lasers in treatment of dentinal hypersensitivity. These materials have been used alone or in combination with an active desensitizing agent.

Aims

The present study aimed to evaluate the use of 1.23% acidulated phosphate fluoride (APF) gel and 810 nm diode laser when used alone and when used together on exposed dentinal tubules.

Settings and Design

Sixty-one extracted teeth were sectioned with a diamond saw and dentin slices were prepared. They were then treated with 37% orthophosphoric acid to remove the smear layer.

Materials and Methods

One of the 61 sections was left as an untreated control, whereas the remaining sixty sections were divided into three groups of twenty sections each. The first set of sections (Group 1) was treated with laser alone, whereas the second set (Group 2) was treated with APF alone. A third set of sections (Group 3) was treated with a combination of laser and APF. The sectioned teeth were then evaluated using field emission scanning electron microscopy, and the percentage of dentinal tubule occlusion was observed.

Statistical Analysis

The Shapiro-Wilk normality test was performed to check for the normal distribution of data, whereas the Kruskal-Wallis test was used to compare the mean percentage of dentinal tubule occlusion between the three groups. The Chi-square test was used to compare the number of images with complete tubular occlusion between the three groups.

Results

A total of 96 images were processed from the sixty sectioned samples. It was seen that the sections in Group 3 showed the highest percentage of dentinal tubule occlusion. Group 3 also showed the highest number of samples with complete dentinal tubule occlusion. Significantly lesser levels of dentinal tubule occlusion were seen in Groups 1 and 2.

Conclusions

Diode lasers were effective in occluding dentinal tubules. The addition of 1.23% APF significantly increased the efficacy and thoroughness of dentinal tubule occlusion. Significantly lesser levels of dentinal tubule occlusion were seen in the sections treated with laser alone and APF alone.

Evaluation of the Effects of 810 nm Diode Laser Alone and in Combination With Gluma© and Chromophore on Dentinal Tubule Occlusion: A Scanning Electron Microscopic Analysis

Introduction: Tooth hypersensitivity is among the most common patient complaints caused by the response of exposed dentin to external stimuli. No definite treatment has been suggested so far for dentin hypersensitivity (DH). This study aimed to compare the efficacy of the diode laser alone and in combination with Gluma and chromophore in occluding opened dentine tubules and the treatment of DH. Methods: This in vitro study was conducted on 30 extracted human third molars kept in 0.1% thymol solution. The teeth were mounted in transparent acrylic resin and the buccal enamel was cut to expose the outer third of dentin. The samples were then divided into 6 groups of negative control (no smear layer removal), positive control (smear layer removal with 6% citric acid application), 810 nm diode laser irradiation (energy density 55.55 J/cm2 , 1 W for 20 seconds in a continuous mode), chromophore (1 mg/mL indocyanine green, ICG) plus diode laser irradiation (1 W, 20 seconds), Gluma plus diode laser irradiation, and Gluma + chromophore + diode laser. Dentinal tubules were evaluated under a scanning electron microscope at x2000 magnification. The mean percentage of the obstruction of dentinal tubules was reported as mean and standard deviation. Considering the normal distribution of the data, two-way ANOVA was applied to compare the efficacy of treatments, and an independent-samples t test was used for pairwise comparisons at P<0.05 level of significance. Results: The highest mean percentage of the obstruction of dentinal tubules was noted in the diode laser/chromophore/Gluma group (65.68±12.31%) while the lowest value was noted in the diode laser/Gluma group (24.33±5.90%). Pairwise comparisons revealed significant differences between all groups (P <0.05) except for the difference between the laser/Gluma/chromophore and laser/ chromophore groups (P =0.20). Conclusion: It seems that chromophore increases the efficacy of the diode laser for the obstruction of dentinal tubules.

Sylc Air Polishing Versus Fluoride Varnish Application in Managing Dentin Hypersensitivity in Non-Carious Cervical Lesions: A Randomized Clinical Trial

Objective:

To determine the effectiveness of Sylc (a bioactive glass-based powder) delivered by an air polishing system compared to fluoride varnish application in managing Dentin Hypersensitivity (DH).

Methods:

This study was a double-blinded randomized clinical trial where 50 participants with DH in at least one tooth with a non-carious cervical lesion were included and randomized into two groups (25 participants each) to receive either Sylc air polishing or fluoride varnish application. Baseline and post-intervention measurements of pain were carried out using evaporative, thermal and tactile stimuli using a modified visual analog scale at 3 minutes, 1, 2, 3and 4 weeks, 6 months and 1 year post-intervention. Data for pain intensity was recorded and analyzed for each group.

Results:

For the three stimuli used, Sylc air polishing showed statistically significant reduction of pain intensity (P<0.05) after 3 weeks and up to 1 year post-intervention. Fluoride varnish application showed a statistically significant reduction of pain intensity in evaporative and thermal stimuli at 1 week post-intervention only.

Conclusion:

Sylc air polishing was effective in relieving pain due to DH after 3 weeks and up to 1 year post-intervention, which showed that it can be used as a long-term treatment for DH.

Sylc Air Polishing Versus Fluoride Varnish Application in Managing Dentin Hypersensitivity in Non-Carious Cervical Lesions: A Randomized Clinical Trial

Objective:

To determine the effectiveness of Sylc (a bioactive glass-based powder) delivered by an air polishing system compared to fluoride varnish application in managing Dentin Hypersensitivity (DH).

Methods:

This study was a double-blinded randomized clinical trial where 50 participants with DH in at least one tooth with a non-carious cervical lesion were included and randomized into two groups (25 participants each) to receive either Sylc air polishing or fluoride varnish application. Baseline and post-intervention measurements of pain were carried out using evaporative, thermal and tactile stimuli using a modified visual analog scale at 3 minutes, 1, 2, 3and 4 weeks, 6 months and 1 year post-intervention. Data for pain intensity was recorded and analyzed for each group.

Results:

For the three stimuli used, Sylc air polishing showed statistically significant reduction of pain intensity (P<0.05) after 3 weeks and up to 1 year post-intervention. Fluoride varnish application showed a statistically significant reduction of pain intensity in evaporative and thermal stimuli at 1 week post-intervention only.

Conclusion:

Sylc air polishing was effective in relieving pain due to DH after 3 weeks and up to 1 year post-intervention, which showed that it can be used as a long-term treatment for DH.

Topical Fluoride to Prevent Root Caries: Systematic Review with Network Meta-analysis

The aim of this systematic review and network meta-analysis was to summarize the direct and indirect clinical evidence on the effectiveness of professionally applied and self-applied topical fluorides in preventing dental root caries. Controlled clinical trials with any follow-up duration were included. MEDLINE, PubMed, Embase, Scopus, and Cochrane Library were searched. Two reviewers independently carried out the selection of studies, data extraction, risk-of-bias assessments, and assessment of the certainty in the evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Fixed effects model and frequentist approach were used in the network meta-analyses. Nine clinical trials involving 4,030 participants were included. Five professionally applied and 7 self-applied topical fluoride agents or combinations were included in the meta-analyses. Compared to control group, 38% silver diamine fluoride solution, 5% sodium fluoride varnish, and 1.2% acidulated phosphate fluoride reduced root caries increment after 2 y (ranging from 0.59 to 0.85 mean decayed or filled root [DF-root]). Fluoride mouth rinse and fluoride toothpaste, used alone or in combination, reduced root caries increment after 1 y (ranging from 0.29 to 1.90 mean DF-root). Among the professionally applied topical fluorides reviewed, an annually applied 38% silver diamine fluoride (SDF) solution combined with oral health education is most likely to be the most effective in preventing dental root caries. Among the reviewed self-applied topical fluoride methods, daily use of a 0.2% sodium fluoride (NaF) mouth rinse is most likely to be the most effective, followed by 1100 ppm to 1500 ppm fluoride toothpaste plus 0.05% NaF mouth rinse, and 1100 ppm to 1500 ppm fluoride toothpaste.

Effect of Chlorhexidine and Fluoride Varnishes on Streptococcus mutans Count and Dental Plaque Index

AbstractThe control of dental plaque by chemical means can be a valuable auxiliary resource for individuals who have difficulties in performing dental plaque control through regular oral hygiene procedures. The aim of this study was to evaluate the effect of chlorhexidine and fluorine varnishes on the levels of Streptococcus mutans (S. mutans) present in the dental biofilm and on the dental plaque index. The study was carried out in a sample comprised thirty-nine schoolchildren between 13 and 15 years of age, distributed into 2 groups. Group I received a single layer of varnish with chlorhexidine and thymol on the maxillary right first molar. Group II received the application of varnish with fluoride following the same methodology. S. mutans count and dental plaque index recording were performed 7 days before the application and 7, 15 and 30 days after the treatment. It was observed that chlorhexidine and fluoride varnishes significantly reduced the number of S. mutans in dental plaque for 30 days (p<0.05). There was no difference between the varnishes. With regard to the dental plaque index, there was no alteration in any of the experimental time periods for both groups. It was concluded that varnishes, mainly those that contain fluoride, can be an interesting alternative for the prevention of dental caries in collective oral health programs. Keywords: Chlorhexidine. Fluorides. Dental Plaque. ResumoO controle da placa dental por meios químicos pode ser um valioso recurso auxiliar para indivíduos que apresentam dificuldades em realizar o controle da placa dental por meio de procedimentos regulares de higiene bucal. O objetivo neste estudo foi avaliar o efeito dos vernizes de clorexidina e de flúor sobre os níveis de Streptococcus mutans (S. mutans) presentes no biofilme dental e sobre o índice de placa dental. O estudo foi realizado em uma amostra composta por 39 escolares, entre 13 e 15 anos de idade, distribuídos em 2 grupos. O grupo I recebeu uma única aplicação de verniz com clorexidina e timol no primeiro molar superior direito. O grupo II recebeu a aplicação de verniz com flúor seguindo a mesma metodologia. A contagem de S. mutans e o índice de placa dental foram registrados 7 dias antes da aplicação e 7, 15 e 30 dias após o tratamento. Observou-se que os vernizes de clorexidina e flúor reduziram significativamente o número de S. mutans na placa dental por 30 dias (p <0,05). Não houve diferença entre os vernizes. Com relação ao índice de placa dental, não houve alteração em nenhum dos períodos experimentais para ambos os grupos. Concluiu-se que os vernizes, principalmente aqueles que contêm flúor, podem ser uma alternativa interessante para a prevenção da cárie dentária em programas coletivos de saúde bucal. Palavras-chave: Clorexidina. Fluoretos. Placa Dentária.

Effect of erosive and abrasive stress on sealing ability of different desensitizers: In-vitro study

This in vitro study examined the sealing ability of different desensitizing agents under a chemo-mechanical stress condition. For the study, a total of 144 extracted, caries-free human third molars were used to produce 1 mm-thick dentin discs. The specimens were divided randomly into four groups: Superseal (SS), Gluma (GL), Gluma Self-etch (GS), and Tooth Coat (TC). For each group, the permeability was measured before and after applying the desensitizer, after being exposed to Coca Cola for 5 minutes, and after 3150 strokes of a brushing abrasion. The decrease in permeability after the erosive and abrasive stress was analyzed by ANOVA and Tukey post hoc test. As a result, the dentin permeability decreased significantly for all desensitizers immediately after application (p < 0.05). SS and GS showed a significant difference in permeability reduction observed immediately after application and after acid action with Coca Cola (p < 0.05). After brushing abrasion, the permeability reduction decreased significantly for all desensitizers tested in this study (p < 0.05). TC showed the largest decrease in dentinal permeability compared to that of the other desensitizers and the differences were significant after brushing abrasion (p < 0.05). All tested desensitizers were effective in reducing dentin permeability. The behavioral characteristics under erosive and abrasive stress varied according to the products used. TC exhibited excellent sealing ability among the other desensitizers.

Effects of different anti-caries agents on microhardness and superficial microstructure of irradiated permanent dentin: an in vitro study

BACKGROUND

To compare different anti-caries agents on microhardness and micromorphology of irradiated permanent dentin in vitro, and try to find the most effective agent to prevent radiation-dentin-destruction.

METHODS

A total of 120 dentin samples were prepared from 60 human teeth and randomly divided into 8 groups (n = 15), [ (1)] blank control [2]; irradiation control [3]; irradiation+ fluoride [4]; irradiation+ casein phosphate polypeptide-amorphous calcium phosphate (CPP-ACP) [5]; irradiation+ CPP-ACP+ fluoride [6]; irradiation+ infiltration resin [7]; irradiation+ infiltration resin+ fluoride [8]; irradiation+ infiltration resin+ CPP-ACP. Seven samples of each groups were chosen randomly for microhardness test and eight for scanning electron microscope observation.

RESULTS

A decrease of microhardness (P < 0.05) and an obvious morphological change were presented on dentin surface after radiotherapy. After applications of anti-caries agents, the morphological destructions were effectively restored. The infiltration resin plus fluoride group (56.00 ± 4.02 Kg/mm2), infiltration resin plus CPP-ACP group (56.05 ± 3.69 Kg/mm2), infiltration resin group (54.70 ± 4.42Kg/mm2) and CPP-ACP plus fluoride group (53.84 ± 6.23Kg/mm2) had the highest dentin microhardness value after radiotherapy, and no statistically significant difference were found between them.

CONCLUSIONS

Infiltration resin, CPP-ACP, fluoride and their pairwise combination can effectively prevent radiation-dentin-destruction. Among them, infiltration resin with CPP-ACP, infiltration resin with fluoride, CPP-ACP with fluoride, and infiltration resin have the most protective effects on irradiation-dentin-destructions.

Calcium Pre-Rinse: Effect on permeability of dentin tubules by fluoride rinse

Background

The aim of this study was to evaluate whether calcium (CaL) solution would enhance the capacity of sodium fluoride (NaF) solution in reducing the permeability of hypersensitive dentin.

Material and Methods

Thirty-two Wistar rats ingested for 45 days acidic isotonic drink (Gatorade, pH 2.7) ad libitum to induce dental erosion. Then, molar teeth received a cold stimulus to confirm the presence and score the intensity of dentin hypersensitivity based on body contraction and noise. Animals were allocated to four groups (n=8), according to the solution(s) applied in the oral cavity: NaF (12 mmol/L, 1 min); CaL (150 mmol/L, 1 min); CaL followed by NaF (CaF+NaF, 1 min each); distilled water (DW, 1 min, as negative control). The animals were euthanized and the mandibles dissected into hemimandibles, which were sealed with sticky wax, except for the occlusal surface of the molar teeth. The samples were immersed in 10% copper sulphate solution and in 1% dithioxamide alcoholic solution (25 min each). The samples were sectioned longitudinally and imaged under optical microscope. Then, dentin permeability was measured as the area of copper ion penetration, using ImageJ software. Photomicrographs were obtained by scanning electron microscopy.

Results

68.7% of animals had body contraction associated or not with noise. One-way ANOVA followed by Tukey´s test indicated that groups treated with NaF solution, whether or not preceded by CaL solution, presented lower permeability than the remaining groups [CaL+NaF: 3405.7 μm2 (±1796.4); NaF: 4111.7 μm2 (±2450.6); CaL: 42254.6 μm2 (±30399.2); DW: 37064.6 μm2 (±21994.4)]. Photomicrographs showed that CaL+NaF group presented an increased proportion of occluded dentin tubules in comparison to the NaF-only group.

Conclusions

Although qualitatively there seems to be a benefit in using CaL pre-rinse, this solution did not quantitatively enhance the capacity of NaF in reducing permeability of hypersensitive dentin.

Key words:Dentin hypersensitivity, Fluoride, Calcium lactate, Animal model.

Effects of silver diamine fluoride/potassium iodide on artificial root caries lesions with adjunctive application of proanthocyanidin

Treatment of carious root surfaces remains challenging due to the complex pathological processes and difficulty in restoring the original structure of root dentine. Current treatments targeting the de-/re-mineralisation processes are not entirely satisfactory in terms of the protection of the dentinal organic matrix and the highly organised structure of dentine. In this in vitro study, a cross-linking agent - proanthocyanidin (PA) was used in conjunction with a fluoride-based treatment - silver diamine fluoride/potassium iodide (SDF/KI) to putatively stabilise the organic dentinal framework as well as strengthen the collagen-mineral phase interaction. The effectiveness of this strategy was evaluated 24 h after application in terms of the distribution of ion uptake and microstructure of dentine after treatment as well as analysis of the nano-mechanical properties using a dynamic behaviour model. Results showed that individual use of SDF/KI significantly improved the surface microhardness and integrated mineral density (Z) up to 60 µm depth and the recovery of creep behaviour of demineralised dentine in the surface area compared to that treated with deionised distilled water (DDW). The combined treatment of PA and SDF/KI achieved a more homogenous mineral distribution throughout the lesions than SDF/KI alone; a more significant incremental increase in surface microhardness and Z was observed. Specifically, a superior effect on the subsurface area occurred with PA + SDF/KI, with significant improvements in microhardness, elastic modulus and recovery of creep behaviour of the demineralised dentine. Application of SDF/KI induced small discrete crystal formation distributed over the dentine surface and PA contributed to the formation of slit-shaped orifices of the dentinal tubules that were partially occluded. STATEMENT OF SIGNIFICANCE: Demographic transitions and improved oral health behaviour have resulted in increased tooth retention in elderly people. As a consequence, the risk of root dentine caries is increasing due to the age-associated gingival recession and the related frequent exposure of cervical root dentine. Root caries is difficult to repair because of the complex aetiology and dentine structure. The recovery of dentine quality depends not only on reincorporation of minerals but also an intact dentinal organic matrix and the organic-inorganic interfacial structure, which contribute to the biomechanics of dentine. With the capability of dentine modification, cross-linking agents were applied with a fluoride regimen, which improved its treatment efficacy of root caries regarding the distribution of ion uptake and recovery of dentine biomechanics.

The effectiveness of home-use photobiomodulation toothbrush for treating dentin hypersensitivity: A pilot study

Background and Aims

Dentin hypersensitivity is a frequent oral condition among patients suffering from gingival recession. Recent studies have suggested that photobiomodulation has the potential to reduce inflammation and relieve pain. The present study aims to assess the effectiveness of a new design of photobiomodulation toothbrush with specific irradiation parameters as a homecare device in treating dentin hypersensitivity and to compare its therapeutic effect with that of fluoride varnish.

Materials and Methods

Thirty patients with gingival recession and dentin hypersensitivity were selected and randomly assigned to three groups of equal size: fluoride varnish, photobiomodulation, and the combination. Dentin pain and hypersensitivity were measured using visual analog scale (VAS) by two distinct tests: the contact test with a periodontal probe and the air blast test on the areas of gingival recession and denuded root; once at baseline and again one month after the initial application of treatments. Laser irradiation was carried out at the wavelength of 660 nm in CW with an output power of 40 mW for 30 seconds per spot (1.2 J per spot, 6 J/cm² energy density, and 200 mW/cm² power density), perpendicularly to denuded root surfaces in non-contact mode.

Results

A significant reduction in dentin pain and hypersensitivity was observed in all three groups. However, the reduction was significantly greater in the combination group.

Conclusion

At-home treatment of dentin hypersensitivity with photobiomodulation toothbrush is a convenient, safe, and effective method for the management of dentin hypersensitivity.