Effects of colchicine on gingival inflammation,apoptosis, and alveolar bone loss in experimental periodontitis

1 Background

The aim of the study was to investigate the effects of colchicine on cytokine production, apoptosis, alveolar bone loss, and oxidative stress in an experimental model of periodontitis in rats.

2 Methods

Forty‐eight rats were divided equally into four groups: healthy (H); periodontitis (P); periodontitis+colchicine low dose (CL, 30 μg/kg/day), and periodontitis+colchicine high dose (CH, 100 μg/kg/day). After 11 days, interleukin (IL) ‐1β, IL‐8, and IL‐10 were analyzed in gingival samples using Enzyme‐Linked ImmunoSorbent Assay. Receptor activator of nuclear factor kappa‐B ligand (RANKL), osteoprotegerin (OPG), total oxidative stress (TOS), total antioxidant status (TAS), and oxidative stress index (OSI) were measured in gingiva and serum. Alveolar bone volume was evaluated via micro‐CT. Apoptotic cells were detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay in histological sections.

3 Results

Colchicine treatment significantly reduced IL‐1β, IL‐8, RANKL, RANKL/OPG, TOS, OSI, and bone volume ratio levels, and increased TAS levels compared to group P (p < 0.05). High dose colchicine treatment (CH) significantly decreased TUNEL+ cell counts compared to group P (p < 0.05).

4 Conclusions

These finding suggest that colchicine has a prophylactic potential for the prevention of periodontal tissue destruction through anti‐inflammatory, anti‐oxidative, anti‐apoptotic, and bone‐protective effects.     

Differential expression of immunologic proteins in gingiva after socket preservation in mini pigs

During healing following tooth extraction, inflammation and the immune response within the extraction socket are related to bone resorption.

Objective

: We sought to identify how the alloplastic material used for socket preservation affects the immune responses and osteoclastic activity within extraction sockets.

Material and Methods

: Using a porcine model, we extracted teeth and grafted biphasic calcium phosphate into the extraction sockets. We then performed a peptide analysis with samples of gingival tissue from adjacent to the sockets and compared the extraction only (EO) and extraction with socket preservation (SP) groups. We also used real-time polymerase chain reaction (PCR) to evaluate the expression level of immunoglobulins, chemokines and other factors related to osteoclastogenesis. Differences between the groups were analyzed for statistical significance using paired t tests.

Results

: Levels of IgM, IgG and IGL expression were higher in the EO group than in the SP group 1 week post-extraction, as were the levels of CCL3, CCL5, CXCL2, IFN-γ and TNF-α expression (p<0.05). In addition, receptor activator of nuclear factor kappa-B ligand (RANKL) was also significantly upregulated in the EO group (p<0.05), as were IL-1β, IL-6 and IL-8 (p<0.05).

Conclusions

: These results suggest that the beneficial effect of socket preservation can be explained by suppression of immune responses and inflammation.     

The Influence of Different Nonsteroidal Anti-Inflammatory Drugs on Alveolar Bone in Rats: An Experimental Study

The aim

The aim of this study was to investigate the effect of dexketoprofen trometamol, meloxicam, diclofenac sodium on any untreated alveolar bone when they are used as drugs for another indication.

Materials and Methods

Twenty eight male Spraque-Dawley rats were randomized into four groups as dexketoprofen trometamol (Group I), meloxicam (Group II), diclofenac sodium (Group III) and control group. Nonsteroidal anti-inflammatory drugs (NSAID) were administered after a fibula fracture for 10 days. Untreated alveolar bone was histopathologically examined for spongious bone density, osteoclastic density and osteoblastic density.

Results

Spongious bone density was lower in study groups (Group I, group II and group III) than the control group (p<0.05). In contrast, the increase in osteoclastic density was observed in other groups apart from the control group (p<0.05). Osteoblastic density was evaluated and it was determined that group II and group III had lower results than the control group (p<0.05) but group I was equal to the control group.

Conclusion

This study showed that systemically administrated NSAIDs have the potential to affect untreated alveolar bone. This should also be considered in long term use of NSAIDs.Key Words: Non-steroidal anti-inflammatory agents, bone remodeling, osteoblast, osteoclast, maxillary bone     

Assessment of Oro-Maxillofacial Trauma According to Gender,Age, Cause and Type of the Injury

Objectives

The occurrence and causes of maxillofacial trauma varies in different regions of the world. The aim of this study was to identify the occurrence, types and causes of maxillofacial injuries according to the age and gender differences in patients treated at the Department of Maxillofacial Surgery, University Hospital Center Osijek, between January 2011 and December 2013.

Materials and methods

A total of 64 patients, 41 males (64.1%) and 23 females (35.9%), aged from 18 to 86 years (mean age 42) participated in the study. Data collected and analyzed included gender, age, cause of injury and the type of maxillofacial injuries.

Results

The most common cause of injuries in both gender groups was falling down (39% males; 65% females). The second leading cause of injuries in males was interpersonal violence (29%) and in females traffic accident (26%) (p<0.05). The most common type of injury in both gender groups was bone injury (50%; in males zygomatic bones 55%, in females mandible 40%) (p>0.05). The most common causes of injuries in the youngest patients was violence (43%), and in others fall (50-70%; p<0.05). The most common reported type of injury in all age groups was bone injury (more than 50%; p>0.05). The majority of the falls and violence caused bone tissue injuries, and soft tissue and dentalveolar injuries were detected in traffic and sports accidents (p>0.05).

Conclusion

Falling down was the most common cause of oro-maxillofacial injuries in both men and women and in all three age groups. The leading type of injury was bone injury. The data obtained from this study provide important information for future prevention from injuries.Key words: maxillofacial trauma, soft-tissue injury, bone injury, dento-alveolar injury     

USE OF CERVICAL VERTEBRAL DIMENSIONS FOR ASSESSMENT OF CHILDREN GROWTH

Objective:

The purpose of this study was to investigate whether skeletal maturation using cephalometric radiographs could be used in a Brazilian population.

Material and Methods:

The study population was selected from the files of the Oral Radiological Clinic of the Dental School of Piracicaba, Brazil and consisted of 128 girls and 110 boys (7.0 to 15.9 years old) who had cephalometric and hand-wrist radiographs taken on the same day. Cervical vertebral bone age was evaluated using the method described by Mito and colleagues in 2002. Bone age was assessed by the Tanner-Whitehouse (TW3) method and was used as a gold standard to determine the reliability of cervical vertebral bone age. An analysis of variance and Tukey''s post-hoc test were used to compare cervical vertebral bone age, bone age and chronological age at 5% significance level.

Results:

The analysis of the Brazilian female children data showed that there was a statistically significant difference (p<0.05) between cervical vertebral bone age and chronological age and between bone age and chronological age. However no statistically significant difference (p>0.05) was found between cervical vertebral bone age and bone age. Differently, the analysis of the male children data revealed a statistically significant difference (p<0.05) between cervical vertebral bone age and bone age and between cervical vertebral bone age and chronological age (p<0.05).

Conclusions:

The findings of the present study suggest that the method for objectively evaluating skeletal maturation on cephalometric radiographs by determination of vertebral bone age can be applied to Brazilian females only. The development of a new method to objectively evaluate cervical vertebral bone age in males is needed.     

A new improved protocol for in vitro intratubular dentinal bacterial contamination for antimicrobial endodontic tests: standardization and validation by confocal laser scanning microscopy

Objectives

To compare three methods of intratubular contamination that simulate endodontic infections using confocal laser scanning microscopy (CLSM).

Material and Methods

Two pre-existing models of dentinal contamination were used to induce intratubular infection (groups A and B). These methods were modified in an attempt to improve the model (group C). Among the modifications it may be included: specimen contamination for five days, ultrasonic bath with BHI broth after specimen sterilization, use of E. faecalis during the exponential growth phase, greater concentration of inoculum, and two cycles of centrifugation on alternate days with changes of culture media. All specimens were longitudinally sectioned and stained with of LIVE/DEAD^® for 20 min. Specimens were assessed using CLSM, which provided images of the depth of viable bacterial proliferation inside the dentinal tubules. Additionally, three examiners used scores to classify the CLSM images according to the following parameters: homogeneity, density, and depth of the bacterial contamination inside the dentinal tubules. Kruskal-Wallis and Dunn’s tests were used to evaluate the live and dead cells rates, and the scores obtained.

Results

The contamination scores revealed higher contamination levels in group C when compared with groups A and B (p<0.05). No differences were observed between group A and B (p>0.05). The volume of live cells in group C was higher than in groups A and B (p<0.05).

Conclusion

The new protocol for intratubular infection resulted in high and uniform patterns of bacterial contamination and higher cell viability in all specimens when compared with the current methods.     

Simultaneous analysis of T helper subsets (Th1, Th2, Th9, Th17, Th22, Tfh,Tr1 and Tregs) markers expression in periapical lesions reveals multiple cytokine clusters accountable for lesions activity and inactivity status

Previous studies demonstrate that the balance between pro- and anti-inflammatory mediators determines the stable or progressive nature of periapical granulomas by modulating the balance of the osteoclastogenic factor RANKL and its antagonist OPG. However, the cytokine networks operating in the development of periapical lesions are quite more complex than what the simple pro- versus anti-inflammatory mediators'' paradigm suggests. Here we simultaneously investigated the patterns of Th1, Th2, Th9, Th17, Th22, Thf, Tr1 and Tregs cytokines/markers expression in human periapical granulomas.

Methods

The expression of TNF-α, IFN-γ, IL-17A, IL23, IL21, IL-33, IL-10, IL-4, IL-9, IL-22, FOXp3 markers (via RealTimePCR array) was accessed in active/progressive (N=40) versus inactive/stable (N=70) periapical granulomas (as determined by RANKL/OPG expression ratio), and also to compare these samples with a panel of control specimens (N=26). A cluster analysis of 13 cytokine levels was performed to examine possible clustering between the cytokines in a total of 110 granulomas.

Results

The expression of all target cytokines was higher in the granulomas than in control samples. TNF-α, IFN-γ, IL-17A and IL-21 mRNA levels were significantly higher in active granulomas, while in inactive lesions the expression levels of IL-4, IL-9, IL-10, IL-22 and FOXp3 were higher than in active granulomas. Five clusters were identified in inactive lesion groups, being the variance in the expression levels of IL-17, IL-10, FOXp3, IFN-γ, IL-9, IL-33 and IL-4 statistically significant (KW p<0.05). Three clusters were identified in active lesions, being the variance in the expression levels of IL-22, IL-10, IFN-γ, IL-17, IL-33, FOXp3, IL-21 and RANKL statistically significant (KW p<0.05).

Conclusion

There is a clear dichotomy in the profile of cytokine expression in inactive and active periapical lesions. While the widespread cytokine expression seems to be a feature of chronic lesions, hierarchical cluster analysis demonstrates the association of TNF-α, IL-21, IL-17 and IFN-γ with lesions activity, and the association of FOXP3, IL-10, IL-9, IL-4 and IL-22 with lesions inactivity.     

ANTIPLAQUE AND ANTIGINGIVITIS EFFECT OF LIPPIA SIDOIDES. A DOUBLE-BLIND CLINICAL STUDY IN HUMANS

Objectives:

The antiplaque and antigingivitis effect of Lippia Sidoides (LS) was evaluated in this in vivo investigation.

Material and Methods:

Twenty-three subjects participated in a cross-over, double-blind clinical study, using 21-day partial-mouth experimental model of gingivitis. A toothshield was constructed for each volunteer, avoiding the brushing of the 4 experimental posterior teeth in the lower left quadrant. The subjects were randomly assigned initially to use either the placebo gel (control group) or the test gel, containing 10% LS (test group).

Results:

The clinical results showed statistically significant differences for plaque index (PLI) (p<0.01) between days 0 and 21 in both groups, however only the control group showed statistically significant difference (p<0.01) for the bleeding (IB) and gingival (GI) index within the experimental period of 21 days. On day 21, the test group presented significantly better results than the control group with regard to the GI (p<0.05).

Conclusions:

The test gel containing 10% LS was effective in the control of gingivitis.     

ORAL MYOFUNCTIONAL AND ELECTROMYOGRAPHIC EVALUATION OF THE ANTERIOR SUPRAHYOID MUSCLES AND TONGUE THRUST IN PATIENTS WITH CLASS II/1 MALOCCLUSION SUBMITTED TO FIRST PREMOLAR EXTRACTION

Objective:

The aim of this study was to assess the existence of myofunctional alterations before and after first premolar extraction in Class II/1 malocclusion patients that could endanger the long-term dental arch stability.

Materials and Methods:

The study was performed by means of morphological, functional and electromyographic analyses in 17 Class II/1 malocclusion patients (group T) and 17 Class I malocclusion patients (group C), both groups with 12-30-year age range (mean age: 20.93 ± 4.94 years).

Results:

Data analyzed statistically by Student’s t-test showed a significant decrease in the maxillary and mandibular dental arch perimeters after orthodontic treatment (p<0.05). The Kruskal-Wallis test analyzed data from tongue posture at rest and during swallowing, not showing significant differences after treatment (groups Tb and Ta) (p>0.05). However, group T differed significantly from group C (p<0.05). The electromyographic data showed that the anterior right and left suprahyoid muscles acted synergistically in both groups, while having a lower myoelectric activity in group T during swallowing.

Conclusions:

Myofunctional alterations observed after the orthodontic treatment in Class II/1 malocclusion seemed to jeopardize the long-term orthodontic stability, making recurrence possible. Further research should be conducted to compare electromyographic data before and after orthodontic treatment in order to corroborate the results of the present investigation.     

Risk factors for maxillofacial injuries in a Brazilian emergency hospital sample

Background

Maxillofacial injuries occur in a significant number of trauma patients. Epidemiological assessments are essential to reaffirm patterns, identify new trends and develop clinical and research priorities for effective treatment and prevention of these injuries.

Objective

The aim of this study was to identify the epidemiological profile and risk factors associated with maxillofacial trauma treated at a referral emergency hospital for the Public Health System in the State Capital of Goiás, Brazil.

Material and Methods

A cross-sectional study was designed including 530 patients with maxillofacial trauma, 76% male, with a mean age of 25.5±15.0 years. Data were collected between May 2003 and August 2004 over weekly shift-working periods. Results: The main causes of trauma were traffic accidents (45.7%) and physical assaults (24.3%), and differences in etiological factors were identified according to gender (p<0.001). The distribution of patients according to age and etiology showed significant differences for traffic accidents (p<0.01), physical assaults (p<0.001), falls (p<0.001) and sport injuries (p<0.01). In the multinomial logistic regression analysis (R² = 0.233; p<0.05), age was associated with injury in traffic accidents and falls (p<0.01), sports-related accidents were associated with males (p<0.05), and alcohol consumption with assaults and traffic accidents (p<0.001). Facial soft tissue lesions were found in 98% of patients and facial fractures in 51%.

Conclusions

The significant association of maxillofacial trauma with young males and alcohol consumption reinforces the need for educational strategies and the development of policies for the prevention and reduction of associated damage in this specific risk group.     

EFFECT OF LIGHT CURING UNIT ON RESIN-MODIFIED GLASS-IONOMER CEMENTS: A MICROHARDNESS ASSESSMENT

Objective:

To evaluate the microhardness of resin-modified glass-ionomer cements (RMGICs) photoactivated with a blue light-emitting diode (LED) curing light.

Material and Methods:

Thirty specimens were distributed in 3 groups: Fuji II LC Improved/GC (RM1), Vitremer/3M ESPE (RM2) and Filtek Z250/ 3M ESPE (RM3). Two commercial light-curing units were used to polymerize the materials: LED/Ultrablue IS and a halogen light/XL3000 (QTH). After 24 h, Knoop microhardness test was performed. Data were submitted to three-way ANOVA and Tukey''s test at a pre-set alpha of 0.05.

Results:

At the top surface, no statistically significant difference (p>0.05) in the microhardness was seen when the LED and QTH lights were used for all materials. At the bottom surface, microhardness mean value of RM2 was significantly higher when the QTH light was used (p<0.05). For RM1, statistically significant higher values (p<0.05) were seen when the LED light was used. No statistically significant difference (p>0.05) was seen at the bottom surface for RM3, irrespective of the light used. Top-to-bottom surface comparison showed no statistically significant difference (p>0.05) for both RMGICs, regardless of the light used. For RM3, microhardness mean value at the top was significantly higher (p<0.05) than bottom microhardness when both curing units were used.

Conclusion:

The microhardness values seen when a LED light was used varied depending on the restorative material tested.     

Photodynamic therapy associated with full-mouth ultrasonic debridement in the treatment of severe chronic periodontitis: a randomized-controlled clinical trial

Background:

Photodynamic therapy (PDT) is a method of microbial reduction which can benefit periodontal treatment in areas of difficult access, such as deep pockets and furcations. The aim of this randomized controlled clinical trial was to evaluate the effects of PDT as an adjunct to full-mouth ultrasonic debridement in the treatment of severe chronic periodontitis.

Material and Methods:

Twenty-two patients with at least one pocket with a probing depth (PD) of ≥7 mm and one pocket with a PD of ≥5 mm and bleeding on probing (BOP) on each side of the mouth were included, characterizing a split mouth design. The control group underwent full-mouth ultrasonic debridement and the test group received the same treatment associated with PDT. The PDT was performed on only one side of the mouth and the initial step consisted of subgingival irrigation with 0.005% methylene blue dye. Two minutes after applying the photosensitizer, the low power laser - AsGaAl (Photon Lase III - PL7336, DMC, São Carlos -São Paulo, Brazil) was applied (660 nm, 100 mW, 9 J, 90 seconds per site, 320 J/cm², diameter tip 600 µm).The following clinical parameters were evaluated: plaque index, gingival index, BOP, gingival recession (GR), PD, and clinical attachment level (CAL). All parameters were collected before, 1, 3 and 6 months after treatment.

Results:

An improvement in BOP, PD and CAL was observed after treatment, in both groups, but without any difference between them. After 6 months, the PD decreased from 5.11±0.56 mm to 2.83±0.47 mm in the test group (p<0.05) and from 5.15±0.46 mm to 2.83±0.40 mm in the control group (p<0.05). The CAL changed, after 6 months, from 5.49±0.76 mm to 3.41±0.84 mm in the test group (p<0.05) and from 5.53±0.54 to 3.39±0.51 mm in the control group (p<0.05).

Conclusion:

Both approaches resulted in significant clinical improvements in the treatment of severe chronic periodontits, however, the PDT did not provide any additional benefit to those obtained with full-mouth ultrasonic debridement used alone.     

Minimally traumatic alveolar ridge augmentation with a tunnel injectable thermo-sensitive alginate scaffold

Injectable bone substitutes and techniques have been developed for use in minimally invasive procedures for bone augmentation.

Objective

: To develop a novel injectable thermo-sensitive alginate hydrogel (TSAH) as a scaffold to induce bone regeneration, using a minimally invasive tunnelling technique.

Material and Methods

: An injectable TSAH was prepared from a copolymer solution of 8.0 wt% Poly(N-isopropylacrylamide) (PNIPAAm) and 8.0 wt% AAlg-g-PNIPAAm. In vitro properties of the material, such as its microstructure and the sustained release of recombinant human bone morphogenetic protein-2 (rhBMP-2), were investigated. Then, with the subperiosteal tunnelling technique, this material, carrying rhBMP-2, was injected under the labial periosteum of the maxillary anterior alveolar ridge in a rabbit model. New bone formation was evaluated by means of X-ray, micro-computed tomography (micro-CT), fluorescence labelling, histological study, and immunohistochemistry study.

Results

: The material exhibited good injectability and thermo-irreversible properties. SEM showed an interconnected porous microstructure of the TSAH. The result of ALP activity indicated sustained delivery of BMP-2 from the TSAH from days 3 to 15. In a rabbit model, both TSAH and TSAH/rhBMP-2 induced alveolar ridge augmentation. The percentage of mineralised tissue in the TSAH/rhBMP-2 group (41.6±3.79%) was significantly higher than in the TSAH group (31.3±7.21%; p<0.05). The density of the regenerating tissue was higher in the TSAH/rhBMP-2 group than in the other groups (TSAH group, positive control, blank control; p<0.05).

Conclusions

: The TSAH provided convenient handling properties for clinical application. To some extent, TSAH could induce ridge augmentation and mineral deposition, which can be enhanced when combined with rhBMP-2 for a minimally invasive tunnelling injection.     

ELECTROMYOGRAPHIC ACTIVITY ASSESSMENT OF INDIVIDUALS WITH AND WITHOUT TEMPOROMANDIBULAR DISORDER SYMPTOMS

Introduction:

Temporomandibular disorders (TMD) present several signs and symptoms that hinder their correct diagnosis, which is imperative on the elaboration of a treatment plan. Over the past years, several studies have been conducted to characterize and classify TMD to better understand these disorders. Therefore, the purpose of this study was to assess the electromyographic behavior of the masseter and temporal muscles in individuals with and without myogenic, arthrogenic and mixed TMD.

Method:

Forty volunteers of both genders responded to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC-TMD) Questionnaire, were submitted to clinical exam and underwent bilateral electromyographic exam of the masseter and temporal muscles.

Results:

No statistically significant difference (p>0.05) was observed during the assessment of isotonic contraction. Regarding isometric contraction, pairing between the mixed TMD group and the asymptomatic subjects did not present significant difference (p>0.05). Comparison between the myogenic and arthrogenic TMD groups and the asymptomatic group showed statistically significant difference (p<0.05). The findings of the present study demonstrated alteration on the muscle contraction pattern of TMD individuals compared to that of asymptomatic patients.     

Histomorphometric analysis of the temporal bone after change of direction of force vector of mandible: an experimental study in rabbits

Objectives

The present study aimed at performing a histological evaluation of the response of temporal bone tissue to a change of direction of the force vector of the mandible in relation to the base of the skull.

Material and methods

Adult rabbits were assigned into four groups with two control and four experimental animals in each group. Experimental animals underwent surgery, which resulted in a change of direction of the force vector on the right temporomandibular joint. Samples were collected after 15, 30, 60 and 90 days for histological analysis.

Results

In the two-way analysis of variance, the effect of group and time was statistically significant (p<0.001). Additionally, a statistically significant interaction between group and time was observed (p<0.001). Control animals showed normal growth and development of the temporal region. In the experimental group, the change in direction of the force vector of the mandible induced significant changes in the temporal bone, with a bone modeling process, which suggests growth of this cranial structure.

Conclusions

The methodology used in this experiment allows us to conclude that the change in direction of the force vector of the mandible in relation to the skull base induces remodeling and modeling processes in the temporal bone. The resumption of normal oral functions after bone healing of the mandibular fracture appears to increase cell activation in the remodeling and modeling of the temporal bone structure. The observation of areas of temporal bone modeling shows the relevance of further investigation on the correlation between the joint structures and craniofacial growth and development.     

Monitoring the effectiveness of root canal procedures on endotoxin levels found in teeth with chronic apical periodontitis

Objective:

The aim of this study was to monitor the effectiveness of root canal procedures by using different irrigants and intracanal medication on endotoxin levels found in root canals of teeth with chronic apical periodontitis.

Material and Methods:

Thirty root canals of teeth with pulpal necrosis associated with periapical lesions were selected and randomly divided into groups according to the irrigants used: GI - 2.5% NaOCl, GII - 2% chlorhexidine (CHX) gel, and GIII - saline solution (SS) (all, n=10). Samples were collected with sterile/apyrogenic paper points before (S1) and after root canal instrumentation (S2), after use of 17% ethylenediaminetetraacetic acid (EDTA) (S3), and after 30 days of intracanal medication (Ca(OH)₂+SS) (S4). A turbidimetric kinetic Limulus Amebocyte Lysate assay was used for endotoxin measurement.

Results:

Endotoxins were detected in 100% of the root canals investigated (30/30), with a median value of 18.70 EU/mL. After S2, significant median percentage reduction was observed in all groups, irrespective of the irrigant tested: 2.5% NaOCl (99.65%) (GI), 2% CHX (94.27%) (GII), and SS (96.79%) (GIII) (all p<0.05). Root canal rinse with 17% EDTA (S3) for a 3-minute period failed to decrease endotoxin levels in GI and a slight decrease was observed in GII (59%) and GIII (61.1%) (all p>0.05). Intracanal medication for 30 days was able to significantly reduce residual endotoxins: 2.5% NaOCl (90%) (GI), 2% CHX (88.8%) (GII), and SS (85.7%) (GIII, p<0.05). No differences were found in the endotoxin reduction when comparing s2 and s4 treatment groups.

Conclusion:

Our findings demonstrated the effectiveness of the mechanical action of the instruments along with the flow and backflow of irrigant enduring root canal instrumentation for the endotoxin removal from root canals of teeth with chronic apical periodontitis. Moreover, the use of intracanal medication for 30 days contributed for an improvement of endotoxin reduction.     

Surface properties of multilayered,acrylic resin artificial teeth after immersion in staining beverages

Objective

To evaluate the effect of staining beverages (coffee, orange juice, and red wine) on the Vickers hardness and surface roughness of the base (BL) and enamel (EL) layers of improved artificial teeth (Vivodent and Trilux).

Material and Methods

Specimens (n=8) were stored in distilled water at 37°C for 24 h and then submitted to the tests. Afterwards, specimens were immersed in one of the staining solutions or distilled water (control) at 37°C, and the tests were also performed after 15 and 30 days of immersion. Data were analyzed using 3-way ANOVA and Tukey’s test (α=0.05).

Results

Vivodent teeth exhibited a continuous decrease (p<0.0005) in hardness of both layers for up to 30 days of immersion in all solutions. For Trilux teeth, similar results were found for the EL (p<0.004), and the BL showed a decrease in hardness after 15 days of immersion (p<0.01). At the end of 30 days, this reduction was not observed for coffee and water (p>0.15), but red wine and orange juice continuously reduced hardness values (p<0.0004). Red wine caused the most significant hardness changes, followed by orange juice, coffee, and water (p<0.006). No significant differences in roughness were observed for both layers of the teeth during the immersion period, despite the beverage (p>0.06).

Conclusions

Hardness of the two brands of acrylic teeth was reduced by all staining beverages, mainly for red wine. Roughness of both layers of the teeth was not affected by long-term immersion in the beverages.     

Influence of root canal sealer on the radiographic appearance of filling voids in maxillary single-rooted teeth

Objective

This study compared the influence of three epoxy resin-based sealers with distinct radiopacities on the observers'' ability to detect root canal filling voids during radiographic analysis.

Material and methods

The root canals of 48 extracted maxillary canines were prepared and divided into three groups. Each group was laterally condensed with one sealer (AH Plus^TM, Acroseal^® or a non-radiopaque sealer), and a longitudinal void was simulated in half of the specimens from each group (n=8). Buccolingual radiographs were obtained and randomly interpreted for voids by a radiologist and an endodontist in a blinded fashion. Teeth were cut and inspected under a microscope to confirm the position of void. Differences in sensitivity and specificity between groups and examiners were compared using the Fisher''s Exact and McNemar tests, respectively (α=0.05).

Results

Significantly lower sensitivity levels (p<0.05) were observed in the coronal portion of fillings performed with both radiopaque sealers. Specificity values for Acroseal^® were significantly higher (p<0.05) in the coronal and apical portions of fillings.

Conclusions

The type of root canal sealer can affect the observers'' ability to detect root canal filling voids during radiographic analysis of upper single-rooted teeth.     

QMix? irrigant reduces lipopolysacharide (LPS) levels in an in vitro model

The presence of endotoxin inside the root canal has been associated with periapical inflammation, bone resorption and symptomatic conditions.

Objectives

To determine, in vitro, the effect of QMix^® and other three root canal irrigants in reducing the endotoxin content in root canals.

Material and Methods

Root canals of single-rooted teeth were prepared. Samples were detoxified with Co-60 irradiation and inoculated with E. coli LPS (24 h, at 37°C). After that period, samples were divided into 4 groups, according to the irrigation solution tested: QMix^®, 17% EDTA, 2% chlorhexidine solution (CHX), and 3% sodium hypochlorite (NaOCl). LPS quantification was determined by Limulus Amebocyte Lysate (LAL) assay. The initial counting of endotoxins for all samples, and the determination of LPS levels in non-contaminated teeth and in contaminated teeth exposed only to non-pyrogenic water, were used as controls.

Results

QMix^® reduced LPS levels, with a median value of 1.11 endotoxins units (EU)/mL (p<0.001). NaOCl (25.50 EU/mL), chlorhexidine (44.10 EU/mL) and positive control group (26.80 EU/mL) samples had similar results. Higher levels were found with EDTA (176.00 EU/mL) when compared to positive control (p<0.001). There was no significant difference among EDTA, NaOCl and CHX groups. Negative control group (0.005 EU/mL) had statistically significant lower levels of endotoxins when compared to all test groups (p<0.001).

Conclusion

QMix^® decreased LPS levels when compared to the other groups (p<0.001). 3% NaOCl, 2% CHX and 17% EDTA were not able to significantly reduce the root canal endotoxins load.     

Altered β-catenin expression in oral mucosal dysplasia: a comparative study

Objective

The current study aimed to investigate the β-catenin expression in oral leukoplakia (OL) with different degrees of epithelial dysplasia and normal oral mucosa.

Material and Methods

Formalin-fixed, paraffin-embedded tissue samples of 39 OL (mild dysplasia n=19, moderate dysplasia n=13, and severe dysplasia n=7), and 10 normal oral mucosa (control group) were submitted to immunohistochemical reactions to anti-β-catenin primary antibody. A qualitative β-catenin analysis was performed based on the percentage of positive cells. The cellular location and the epithelial layer were also considered. The Chi-square test and the Fisher’s exact test were used to verify possible differences in the β-catenin expression among the OL groups. A p-value of <0.05 was considered statistically significant.

Results

Membranous expression of β-catenin in parabasal and basal layers was gradually lost in the higher degrees of epithelial dysplasia. In normal oral mucosa, β-catenin was detected only in the cytoplasmic membrane. However, a significant increase in cytoplasmic β-catenin could be observed between mild and moderate dysplasia (Fisher Exact test - p<0.001) and between mild and severe dysplasia (p<0.001).

Conclusions

The β-catenin cytoplasmic expression observed in this study may represent the initial stage of modifications in the E-cadherin-catenin complex, along with morphological cellular changes.