Effects of proanthocyanidin-functionalized hydroxyapatite nanoparticles on dentin bonding.

OBJECTIVES: To evaluate the effect of proanthocyanidin-functionalized hydroxyapatite nanoparticles (nHAp_PA) used as pretreatment at different concentrations on the microtensile bond strength (µTBS) and endogenous enzymatic activity (MMPs) on pH-cycled dentin after 24 h and 6 months of artificial aging. MATERIALS AND METHODS: Fifty human sound dentin blocks were randomly assigned to 5 groups (n = 10): (i) negative control (no treatment); (ii) positive control (pH-cycling); (iii) pH-cycling + 2% nHAp_PA for 60s; (iv) pH-cycling + 6.5% nHAp_PA for 60s; (v) pH-cycling + 15% nHAp_PA for 60s. A self-etch adhesive was used for bonding procedures before resin composite build-ups. Specimens were tested with the µTBS test after 24 h and 6 months of laboratory storage. The proteolytic activity in each group was evaluated with gelatin zymography and in situ zymography. Data were statistically analyzed (p < 0.05). RESULTS: At 24 h, the µTBS of the experimental groups were significantly higher than the controls (p ≤ 0.001), and no differences were observed between different concentrations (p > 0.05). Artificial aging significantly decreased bond strength in all groups (p ≤ 0.008); however, nHAp_PA 2% still yielded higher bonding values than controls (p ≤ 0.007). The groups pretreated with nHAp_PA exhibited lower MMP-9 and MMP-2 activities compared to the positive control group and almost the same enzymatic activity as the negative control group. In situ zymography showed that after 6 months of aging, nHAp_PA 2% and nHAp_PA 6,5% decreased enzymatic activity as well as the negative control. CONCLUSIONS: Dentin pretreatment with nHAp_PA increased the bonding performance of a self-etch adhesive and decreased MMP-2 and MMP-9 activities after 6 months.

Wear and roughness analysis of two highly filled flowable composites.

This in vitro study aimed to evaluate surface roughness and wear of highly filled flowables and traditional packable composites. Additionally, the effect of polymerization time on these parameters was evaluated. Two flowable higly filled composites (CMf-Clearfil Majesty ES flow-low viscosity, Kuraray and GUf-Gaenial Universal Injectable, GC) and two packable composites (CM-Clearfil Majesty ES-2, Kuraray and GU-Gaenial A'CHORD, GC) were used to create 160 specimens (n = 40;8 × 6 × 4mm). For each tested material, two subgroups were considered according to the polymerization time (n = 20): 10 s or 80 s. After setting, the specimens were subjected to chewing simulations (240.000 cycles, 20N), and wear was measured by the laser integrated in the chewing simulator. The surface roughness was measured using a rugosimeter, before and after chewing cycles. Two representative specimens per group were observed under scanning electron microscope (SEM). Data were collected and statistically analyzed (p < 0.05). Wear analysis highlighted statistically significant differences between the groups: CMf10-CMf80 (p = 0.000), CMf10-CM10 (p = 0.019), CMf10-GUf10 (p = 0.002), CM10-CM80 (p = 0.000), CM80-GUf80 (p = 0.02), GUf10-GUf80 (p = 0.000), GUf10-GU10 (p = 0.043) and GU10-GU80 (p = 0.013). Statistically significant differences in surface roughness were highlighted between the groups: CMf10-CMf80 (p = 0.038), CMf80-CM80 (p = 0.019), CMf80-GU80 (p = 0.010), CM80-GUf80 (p = 0.34) and GUf80-GU80 (p = 0.003). Surface roughness and wear of highly filled flowable composites were comparable to that of traditional paste composites. Furthermore, a longer curing time leads to an improvement in the mechanical properties of the composites. Highly filled flowables can be a valid alternative to paste composites in occlusal areas due to its similar surface roughness and wear values, especially when overcured.

Push-out bond strength and SEM fractographical analysis of hollow fibre posts used with self-adhesive resin cement: a pilot study.

Detachment is the major cause of failure of endodontic fibre posts. Hollow posts have been recently introduced to overcome such issue. The primary aim of this pilot study was to compare the push-out bond strength of hollow posts and traditional solid posts. Eight round-shaped single-canal premolars extracted for periodontal reason were selected as sample and equally randomized into two groups: (i) traditional solid fibre posts-TECH21xop and ii) hollow fibre posts-TECHOLE. A dual-curing self-adhesive cement (new TECHCEM) was used for posts placement. Six horizontal sections-two from each portion of the root (coronal, middle and apical)-were obtained from each sample root, yielding a total of 24 sections for each group. Push-out test was performed on the sections and bond strength values were compared between groups and within each group. Scanning electron microscope (SEM) fractographical analysis was conducted on each section. Additional SEM and EDX analyses were performed on new samples of both posts, to assess fibres density and distribution, and the chemical composition of the fibres and the matrix. Hollow posts showed a significantly higher push-out bond strength (6.36 ± 1.22 MPa) than solid posts (3.64 ± 1.62 MPa). Among the three root portions of the same group, there was no significant difference in bond strength. In both groups, the most frequent type of fracture was a mixed adhesive failure with the cement covering 0 to 50% of the post perimeter. Hollow post fibres appear more similar in size and have a more homogeneous distribution, compared to solid posts. The two post types also have different chemical compositions.

Effect of adhesive strategy on resin cement bonding to dentin.

OBJECTIVE: The cement bonding strategy and the polymerization mode can influence the prognosis of indirect restorations. The microtensile bond strength (µTBS) and dentin endogenous enzymatic activity of a dual-cure resin cement (PV5) used in combination with two dentin surface conditioners (accelerator-enhancer primer, TP or universal adhesive, UA) were evaluated. MATERIALS AND METHODS: PV5 was used to lute composite overlays after dentin treatment with TP or UA. The resin cement was self-cured, SC (1 h at 37 °C) or dual-cured, DC (20 s light-cure followed by 15 min self-cure at 37°C). The µTBS test, fractographic analysis, and the in situ zymography evaluations were performed after 24 h (T0 ) or 1 yr (T12 ) of artificial storage. Data were statistically analyzed (α = 0.05). RESULTS: TP/DC obtained the highest adhesive strengths (45 ± 9 and 36.6 ± 8), while UA/SC (17 ± 8 and 11 ± 4) the lowest, both at T0 and T12 , respectively. DC resulted in superior bonding values than the SC, independent of the dentin surface treatment (p < 0.05). The type of adhesive, curing mode and aging influenced the gelatinolytic activity (p < 0.05). CONCLUSIONS: The dual-cure resin cement used in combination with its accelerator-enhancer primer showed superior bonding performances with respect to universal adhesive. Dual-curing the resin cement was determinant to enhance bonding capability over time, independent of the adhesive strategy. CLINICAL RELEVANCE: Clinicians must be aware to faithfully follow manufacturer's recommendation regarding the adhesive strategy suggested with the resin cement used.

Endogenous Enzymatic Activity in Dentin Treated with a Chitosan Primer.

The aim of this study was to evaluate the effect of different concentrations of chitosan polymer on dentinal enzymatic activity by means of gelatin and in situ zymography. Human dentin was frozen and ground in a miller. Dentin powder aliquots were demineralized with phosphoric acid and treated with three different concentrations of lyophilized chitosan polymer (1, 0.5 and 0.1 wt%) dissolved in distilled water. Dentin proteins were extracted from each experimental group and electrophoresed under non-reducing conditions in 10% SDS-PAGE containing fluorescein-labeled gelatin. After 48 h in the incubation buffer at 37 °C, proteolytic activity was registered under long-wave UV light scanner and quantified by using Image J software. Furthermore, additional teeth (n = 4) were prepared for the in situ zymographic analysis in unrestored as well as restored dentin pretreated with the same chitosan primers. The registered enzymatic activity was directly proportional to the chitosan concentration and higher in the restored dentin groups (p < 0.05), except for the 0.1% chitosan primer. Chitosan 0.1% only showed faint expression of enzymatic activity compared to 1% and 0.5% concentrations. Chitosan 0.1% dissolved in water can produce significant reduction in MMPs activity and could possibly contribute to bond strength preservation over time.

Isolation through rubber dam to prevent COVID-19 exposure during flapless trans-crestal sinus lift procedures.

In 2020, a highly infective new pathogen (Sars-CoV-2) spread from China to the whole globe, and became responsible of an acute respiratory syndrome, often asymptomatic but potentially lethal, named COVID-19. Airborne and direct contact contamination are the major infection pathways of Sars-CoV-2 and it has been shown that virus spread can also happen in absence of clinical symptoms. SARS-CoV-2 transmission during dental procedures can happen through inhalation of droplets from infected patients or direct contact with mucous membranes, oral fluids, and contaminated instruments. Both sinus lift and implant surgeries often involve bleeding and exposure to oral fluids, and a rubber dam could be used to reduce direct contact and the amount of potentially infected aerosol. The aim of this short case presentation is to illustrate how the use of a rubber dam could be extremely useful in preventing COVID-19 exposure during flapless trans-crestal sinus lift procedures.

Prognostic value of a simplified method for periodontal risk assessment during supportive periodontal therapy.

AIM: To evaluate the association between risk scores generated with a simplified method for periodontal risk assessment (Perio Risk), and tooth loss as well as bone loss during supportive periodontal therapy (SPT). MATERIALS & METHODS: Data related to 109 patients (42 males; mean age: 42.2 ± 10.2 years, range 22-62) enrolled in a SPT programme for a mean period of 5.6 years were retrospectively obtained at two specialist periodontal clinics. Patients were stratified according to Perio Risk score (on a scale from 1 - low risk to 5 - high risk) as calculated at the end of active periodontal therapy. Risk groups were compared for tooth loss as well as the changes in radiographic bone levels occurred during SPT. RESULTS: The mean number of teeth lost per patient during SPT varied from 0 to 1.8 ± 2.5 for patients with a risk score of 1 and 5 respectively (p = 0.041). Mean radiographic bone loss during SPT was ≤0.5 mm in all risk groups, without significant inter-group differences. CONCLUSIONS: Periodontal risk assessment according to Perio Risk may help to identify patients at risk for tooth loss during SPT.

Safe New Approach to the Lingual Flap Management in Mandibular Augmentation Procedures: The Digitoclastic Technique.

PURPOSE: This article describes the digitoclastic technique, an innovative procedure for coronal displacement of the lingual flap. The new technique has the potential to obtain primary flap closure without surgical risks to the anatomical structures on the lingual side of the mandible. MATERIALS AND METHODS: Reconstruction of an atrophic mandible with guided tissue regeneration (guided bone regeneration) and implant placement is described, using the digitoclastic technique to displace the lingual flap coronally. RESULTS: Coronal flap displacement was sufficient to obtain complete passive coverage of the grafted area. No bleeding or neurosensory complications were recorded, and no membrane exposure occurred. CONCLUSIONS: The digitoclastic technique reduces the risk of damage to the lingual nerve and minimizes the amount of bleeding during surgery, allowing progressive and controlled retraction of the flap until the desired detachment is achieved.

Microbiological Distribution of Six Periodontal Pathogens Between Untreated Italian and Dutch Periodontal Patients.

PURPOSE: To compare prevalence and microbial load of six periodontal pathogens between Italian and Dutch patients affected by chronic periodontitis, using oligonucleotide probe technology. MATERIALS AND METHODS: Subgingival plaque samples data from 352 Italians and 115 Dutch periodontal patients were analysed and compared. Bleeding on probing, suppuration, probing pocket depth, clinical attachment level, age, gender, ethnicities and smoking habits were recorded. Presence and level of bacterial species were determined by realtime polymerase chain reaction under the identical microbiological protocol. Statistical analysis was performed using the chi-square test, Mann-Whitney U-test and binary unconditional logistic regression (α = 0.05). RESULTS: Between populations, only Treponema denticola and Porphyromonas gingivalis differed significantly, being more prevalent in the Italian group (p = 0.0001). Except for Tannerella forsythia, all bacterial loads differed significantly: Treponema denticola (p = 0.0001) and Prevotella intermedia (p = 0.001) were higher in Italians, while Porphyromonas gingivalis (p = 0.001), Fusobacterium nucleatum (p = 0.03) and Aggregatibacter actinomycetemcomitans (p = 0.001) were higher in Dutch patients. CONCLUSIONS: Significant differences in prevalence and bacterial load of periodontal pathogens exist between Italian and Dutch patients affected by chronic periodontitis. The microbiological profile, and particularly the bacterial load of pathogens, varied significantly between populations.

Periodontal status after surgical-orthodontic treatment of labially impacted canines with different surgical techniques: A systematic review.

INTRODUCTION: Good periodontal status is essential for a successful treatment outcome of impacted maxillary canines. Whereas the surgical technique used for tooth uncovering has been shown not to affect the final periodontal status of palatally impacted canines, its effect on labially impacted canines is still unclear. METHODS: Searches of electronic databases through January 2015 and reference lists of relevant publications were used to identify studies evaluating the periodontal status of labially impacted canines after combined surgical-orthodontic treatment. Two reviewers independently screened the articles, extracted data, and ascertained the quality of the studies. RESULTS: Ninety-one studies were identified; 3 were included in the review. No included study examined the periodontal outcome of the closed eruption technique. Excisional uncovering was reported to have a detrimental effect on the periodontium (bleeding of the gingival margin, 29% vs 7% in the control group; gingival recession, -0.5 mm [SD, 1.0] vs -1.5 mm [SD, 0.8] in the control group; and width of keratinized gingiva, 2.6 mm [SD, 1.4] vs 4.1 mm [SD, 1.5] in the control group). Impacted canines uncovered with an apically positioned flap had periodontal outcomes comparable with those of untreated teeth. CONCLUSIONS: The current literature is insufficient to determine which surgical procedure is better for periodontal health for uncovering labially impacted canines.

Evaluation of clinical effectiveness and subjective satisfaction of a new toothbrush for postsurgical hygiene care: a randomized split-mouth double-blind clinical trial.

The aim of this RCT was to evaluate plaque control and gingival health promotion effectiveness of a new toothbrush with extra-soft filaments in postsurgical sets. Ten consecutive patients with at least two scheduled symmetrical periodontal surgeries were selected. Following the first periodontal surgery, a test (TB1) or control (TB2) toothbrush was randomly assigned. After the second surgery, the remaining toothbrush was given. Patients were asked to gently wipe the surgical area from days 3 to 7 postoperatively and to gently brush using a roll technique from day 7 till the end of the study. Baseline evaluation took place on the day of surgery and follow-ups were performed at days 7, 14, and 30 postoperatively. A more evident PI reduction was recorded for test toothbrush where a regular decrease was observed till day 14; then, this parameter tended to stabilize, remaining however lower than that recorded for the control toothbrush. There were no statistical differences in the GI between test and control toothbrushes. All patients introduced the test toothbrush at surgical site at third day; the control toothbrush was introduced within a mean of 9 days. The introduction of the test toothbrush 3 days after periodontal surgery may be recommended.

Periodontal Side Effect During Orthopedic Face Mask Therapy.

A 7-year-old patient exhibited gingival recession of tooth #41 and severe plaque accumulation after 3 months of face mask therapy. The recession improved only slightly after appropriate oral hygiene instructions and motivation. Decisive improvement began when the vertical chin pad extension was reduced to avoid pressure on the affected area.

Color match of single-shade restorations after professional dental bleaching: An in vitro study.

Background: Restorative dentistry aims to reproduce natural tooth shades through resin composites that must be layered to obtain colors, opacities, and translucencies, and therefore, clinical success is operator skill dependent. Aims: The purpose of this study is to evaluate the color shift of single-shade composite restorations before and after dental bleaching. Materials and Methods: Eighty human extracted posterior teeth were restored with four single-shade composites (Omnichroma OM; Clearfil Majesty ES-2 Universal CL; Essentia Universal ES; Venus Diamond One VE) (n = 20 each). Standardized V class cavities were prepared on buccal side. VITA Easyshade V spectrophotometer was used to register VITA color and color coordinates 24 h before (T0), 24 h after (T1), and 1 week after (T2) dental bleaching (Opalescence Boost PF 40%). Color differences (ΔEab) and (ΔWID) were calculated and subjected to statistical analysis. Statistical Analysis: Categorical variables were analyzed using Pearson Chi-square, and data from color coordinates were analyzed using one-way analysis of variance and Tukey's multiple comparison test with Bonferroni correction. Paired t-tests were performed to compare continuous measures between groups and treatment time. Results: Instrumental evaluations revealed statistically significant differences between materials (P < 0.05) with lower values for ES and VE samples followed by CL and OM at T0 and T1. At T2, OM and CL ΔEab values decrease getting closer to ES and VE. Conclusion: Single-shade composites seem to match with the surrounding bleached tooth.

Color Stability Assessment of Single- and Multi-Shade Composites Following Immersion in Staining Food Substances.

Composite resins are the material of choice for direct restorations, and their success depends mainly on their color stability, since discoloration causes color mismatch, and consequent patient dissatisfaction. A single- and a multi-shade resin were compared in order to evaluate their pigmentation after immersion in staining substances and to investigate the effect of the polymerization time on their color stability. Two-hundred-and-forty composite specimens were created, half made of a single-shade (Group ONE, n = 120) and half of a multi-shade composite (Group OXP, n = 120). Each group was further divided into ONE30 (n = 60) and OXP30 (n = 60), polymerized for 30″, and ONE80 (n = 60) and OXP80 (n = 60), polymerized for 80″. Randomly, the specimens were immersed in turmeric solution, soy sauce, energy drink, or artificial saliva. By means of a spectrophotometer, ΔE00 and WId were calculated at 24 h (T0), at 7 (T1), and 30 (T2) days. Single-shade composites showed statistically significant differences in color change from the turmeric solution, energy drink, and soy sauce than the multi-shade composites (p < 0.005), showing a higher discoloration potential. The polymerization time did not have significative effects on color stability. Single-shade composites showed more color change than multi-shade systems after immersion in staining substances, and the curing time did not influence color variations.

Comparisons of ammonia- and water-based silver-containing solutions on dentin bonding and enzymatic activity: 1-yr evaluation.

OBJECTIVE: To evaluate the effects of an ammonia-based and a water-based silver-containing solutions on bonding performance and matrix-metalloproteinases (MMPs) activity of a universal adhesive to dentin after 1 year of artificial aging. METHODS: Mid-coronal dentin surfaces of 60 sound human molars were exposed and the following groups were formed according to the surface pre-treatment and etching mode of the universal adhesive (Zipbond Universal, SDI) (n = 10): G1) Zipbond in the self-etch mode (ZSE); G2) Riva Star (SDI) applied before ZSE; G3) Riva Star Aqua (SDI) applied before ZSE; G4) Zipbond in the etch-and-rinse mode (ZER); G5) Riva Star applied before ZER; G6) Riva Star Aqua applied before ZER. The specimens were sectioned and subjected to microtensile bond strength (µTBS) test at baseline (T0) and after 12 months (T12) of artificial storage. Scanning electron microscope (SEM) and energy dispersive spectroscopy analysis (EDS) were also conducted. Three additional molars per group were processed for the in situ zymography analysis at T0 and T12. Data were statistically analyzed (p < 0.05). RESULTS: Dentin pre-treatments and aging decreased bonding values, regardless of the etching mode (p < 0.05). No differences in µTBS were observed between the two silver-containing solutions, both at T0 and T12. Riva Star Aqua and etching significantly increased the MMPs activity, independent of the storage period (p < 0.05). SIGNIFICANCE: Dentin surface pre-treatment with silver-containing solutions negatively affects the bonding performances of resin composite restorations placed with a universal adhesive. However, the ammonia-based product Riva Star might show better stability in the long term, due to lower activation of MMPs.

Changes in Oral Health and Dental Esthetic in Smokers Switching to Combustion-Free Nicotine Alternatives: Protocol for a Multicenter and Prospective Randomized Controlled Trial.

BACKGROUND: Although the detrimental effects of conventional combustible cigarettes on oral health and dental esthetics are well known, there is limited information about the long-term impact of combustion-free nicotine alternatives (C-F NA) such as e-cigarettes or heated tobacco products. OBJECTIVE: This multicenter, prospective, 3-parallel-arm randomized controlled trial will investigate whether switching from combustible cigarettes to C-F NA will lead to measurable improvements in oral health parameters and dental esthetics over 18 months in adult smokers with limited gum disease. METHODS: Regular smokers not intending to quit and without clinical signs of periodontitis will be randomly assigned (1:4 ratio) to either standard of care with brief cessation advice (control group; arm A) or C-F NA use (intervention group; arm B). The study will also include a reference group of never smokers (reference group; arm C). The primary end point is the change in the Modified Gingival Index (MGI) score from baseline between the control arm (arm A) and the intervention arm (arm B) at the 18-month follow-up. In addition, the study will analyze the within- and between-group (arms A, B, and C) changes in MGI assessment, plaque imaging, dental shade quantitation, tooth stain scores, and oral health-related quality of life questionnaires measured at each study time point. All participants will attend a total of 7 clinic visits: screening, enrollment, and randomization (visit 0); baseline visit-day 14 (visit 1); day 90 (visit 2); day 180 (visit 3); day 360 (visit 4); and day 540 (visit 5). This multicenter study will be conducted in 4 dental clinics in 4 countries. The statistical analysis will involve descriptive statistics for continuous and categorical data. Primary end points will undergo tests for normality and, based on distribution, either a 2-sided t test or Mann-Whitney U test. Linear mixed model with random factors center and study arms by center will also be applied. Secondary end points, including MGI assessment and quality of life, will be subjected to similar tests and comparisons. Only if one value of the parameter MGI is missing after day 1, the last available observation will be carried forward. The analysis will be performed on the substituted data. Secondary parameters will not have missing value replacement. RESULTS: Participant recruitment began in October 2021, and enrollment was completed in June 2023. Results will be reported in 2025. CONCLUSIONS: This will be the first study to provide key insights into oral health benefits or risks associated with using C-F NA in smokers who are seeking alternatives to cigarette smoking. TRIAL REGISTRATION: ClinicalTrials.gov NCT04649645; https://clinicaltrials.gov/ct2/show/NCT04649645. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/53222.

Effect of bleaching on the color match of single-shade resin composites.

PURPOSE: To evaluate the color match of single-shade resin composites before and after bleaching procedures, through instrumental and visual analyses. METHODS: Class V cavities were created on the buccal surfaces of 80 extracted human molars, restored with 4 single-shade composites (Omnichroma; Clearfil Majesty ES-2 Universal; Essentia Universal; Venus Diamond One). A spectrophotometer (VITA Easyshade V) was used to evaluate the tooth/resin color match before (T0), and 24 h (T1) and one week (T2) after dental bleaching (Opalescence Boost PF 40%). Color variations (ΔE00) were calculated and statistically analyzed (P < 0.05). Visual analysis was performed before and after tooth bleaching. RESULTS: Spectrophotometric evaluations revealed statistically significant differences between materials at T0, T1, and T2 (P < 0.05). Visual analysis reported excellent and very good grades (0 and 1, respectively), irrespective of the materials and timepoints. CONCLUSION: Data seem to indicate that single shade composites are able to shift their color when the surrounding tooth undergoes bleaching effects. Single-shade composites seem to achieve a good color match with the surrounding tooth structure, before and after professional bleaching.

Glutaraldehyde-based desensitizers' influence on bonding performances and dentin enzymatic activity of universal adhesives.

OBJECTIVES: To evaluate the influence of two glutaraldehyde-based desensitizers (L: GLUMA Desensitizer, Heraeus Kulzer and G: GLUMA Desensitizer PowerGel) prior to the adhesive procedures on microtensile bond strength (µTBS) to dentin and endogenous enzymatic activity. METHODS: Noncarious human third molars (N = 48) were cut to expose middle coronal dentin. Six experimental groups were formed according to the dentin pre-treatment (L or G) and the universal adhesives (IBU - iBond universal, Kulzer or AU - Adhese Universal, Ivoclar Vivadent) used in the self-etch mode (n = 8): 1) L/IBU; 2) G/IBU; 3) IBU; 4) L/AU; 5) G/AU; 6) AU. Specimens were cut into sticks and stressed until failure after 24 h (T0) or 1 yr of aging (T12). Additional 4 teeth were used for in situ zymography evaluation and data were statistically analyzed (α = 0.05). RESULTS: Dentin pre-treatment, adhesive and aging statistically influenced bond strength and enzymatic activity (P<0.001). AU demonstrated higher bond strength values than IBU (P<0.001). The L resulted in higher bond strength compared to the G and control groups (P<0.001). aging statistically influenced bonding performance, especially when no dentin pre-treatment was performed (P<0.001). In situ zymography revealed that at baseline the control groups exhibited lower interfacial fluorescence compared to the experimental groups, irrespective of the adhesive used (P<0,001). However, after 1 yr of artificial storage, no differences were found among the groups (P>0.05). CONCLUSIONS: Glutharldeadeyde-based products increased bond strength and determined a stabilization of the adhesive interface over time apparently not related to the MMPs inhibition. CLINICAL SIGNIFICANCE: The results of this in vitro study suggest that the application of glutaraldehyde-based desensitizers prior to the adhesive procedures when associated with universal adhesives could result in increased bond strength and stabilization of the adhesive interface over time.

Shaping ability of Procodile and R6 Reziflow nickel-titanium reciprocating instruments in curved mesial root canals of mandibular molars: A MicroCT study.

To compare the shaping ability of Procodile and R6 Reziflow instruments used in reciprocating motion in severely curved root canals, assessed with micro-computed tomography (µCT). Fourteen extracted human mandibular first molars were randomly assigned to two instrumentation techniques (n = 14 mesial root canals): Procodile or R6 Reziflow. For both groups, root canals were prepared to the working length up to a size 25, .06 taper. Molars were virtually divided into apical, middle and coronal thirds and µCT was used to scan all samples pre- and post-root canal. Canal transportation, centring ability, volume, surface area and unprepared area were evaluated. Geometrical parameter changes were compared with preoperative values (one-way analyses of variance and Tukey multiple comparison post-hoc test) between groups and Student t-test within groups (α = 0.05) Significantly less transportation was observed associated with the Procodile technique in the molar's coronal third compared to the R6 Reziflow technique (p < .05). No significant differences in root canal centring ability, volume, surface area and unprepared area were observed. Procodile showed a lower percentage increase of surface area compared to R6 Reziflow (p < .05). The Procodile and R6 Reziflow techniques applied to first molar root canal performed similarly except for the less transportation observed in the coronal third using Procodile. RESEARCH HIGHLIGHTS: MicroCT analysis of canal geometry before and after instrumentation revealed that Procodile and R6 Reziflow showed a similar shaping ability to shape curved root canals without substantially modifications of the original tooth anatomy.

Management of a deeply impacted mandibular third molar and associated large dentigerous cyst to avoid nerve injury and improve periodontal healing: case report.

As dentigerous cysts increase in size, the risk of postsurgical complications increases as well. Emphasis is usually placed on the risk of neurologic damage caused by trauma during and after surgical removal and of mandibular fracture resulting from the large residual bone defect. However, influence on the periodontal status of neighbouring teeth should also be taken into account. In this article, we present an interdisciplinary, safe, minimally invasive approach to treating large dentigerous cysts associated with deeply impacted third molars. A dentigerous cyst is an epithelial-lined pathologic cavity that develops in association with the crown of an unerupted tooth and appears radiographically as a well-circumscribed pericoronal radiolucency. The cyst not only inhibits the eruption of the associated tooth (usually, a mandibular third molar), but can also carry it to unusual positions in the jaw. Dentigerous cysts may enlarge causing extensive bone resorption and even pathologic fracture. The greater the size of the cyst, the higher the risk of neurologic damage caused by trauma during and after surgical removal and of mandibular fracture resulting from the postoperative bone defect.7,8 Moreover, the removal of large cysts can lead to a severe infrabony defect at the root surface of adjacent teeth, jeopardizing their long-term periodontal health. "Orthodontic extraction" is a combined orthodontic-surgical approach that decreases the risk of neurologic complications and facilitates the surgical extraction of impacted mandibular third molars that are in close contact with the mandibular canal, even when associated with cystic lesions.13 This case report shows that the interdisciplinary approach is also effective in preventing periodontal breakdown on the distal surface of the adjacent second molar.