Temperature rise during Er:YAG cavity preparation of primary enamel

This study aimed to assess in vitro thermal alterations taking place during the Er:YAG laser cavity preparation of primary tooth enamel at different energies and pulse repetition rates. Forty healthy human primary molars were bisected in a mesio-distal direction, thus providing 80 fragments. Two small orifices were made on the dentin surface to which type K thermocouples were attached. The fragments were individually fixed with wax in a cylindrical PlexiglassA (R) abutment and randomly assigned to eight groups, according to the laser parameters (n = 10): G1 -aEuro parts per thousand 250 mJ/ 3 Hz, G2 -aEuro parts per thousand 250 mJ/ 4 Hz, G3 -aEuro parts per thousand 250 mJ/ 6 Hz, G4 -aEuro parts per thousand 250 mJ/10 Hz, G5 -aEuro parts per thousand 250 mJ/ 15 Hz, G6 -aEuro parts per thousand 300 mJ/ 3 Hz, G7 -aEuro parts per thousand 300 mJ/ 4 Hz and G8 -aEuro parts per thousand 300 mJ/ 6 Hz. An area of 4 mm(2) was delimited. Cavities were done (2 mm long x 2 mm wide x 1 mm thick) using non-contact (12 mm) and focused mode. Temperature values were registered from the start of laser irradiation until the end of cavity preparation. Data were analyzed by one-way ANOVA and Tukey test (p a parts per thousand currency signaEuro parts per thousand 0.05). Groups G1, G2, G6, and G7 were statistically similar and furnished the lowest mean values of temperature rise. The set 250 mJ/10 and 15 Hz yielded the highest temperature values. The sets 250 and 300 mJ and 6 Hz provided temperatures with mean values below the acceptable critical value, suggesting that these parameters ablate the primary tooth enamel. Moreover, the temperature elevation was directly related to the increase in the employed pulse repetition rates. In addition, there was no direct correlation between temperature rise and energy density. Therefore, it is important to use a lower pulse frequency, such as 300 mJ and 6 Hz, during cavity preparation in pediatric patients.

Intranasal tooth and associated rhinolith in a patient with cleft lip and palate

We report the case of a 9-year-old girl who presented with a complaint of a malodorous bloody discharge from the left naris. The patient had previously undergone a complete repair of left-sided cleft lip and palate. Clinical examination revealed hyperplasia of the nasal mucosa on the left side. X-ray examination of the nasal cavity demonstrated a radiopaque structure that resembled a tooth and a radiopaque mass similar to an odontoma that was adherent to the root of the suspected tooth. With the patient under general anesthesia, the structure was removed. On gross inspection, the structure was identified as a tooth with a rhinolith attached to the surface of its root. Microscopic examination revealed normal dentin and pulp tissue. A nonspecific inflammatory infiltrate was observed around the rhinolith, and areas of regular and irregular mineralization were seen. Some mineralized areas exhibited melanin-like brownish pigmentation. Areas of mucus with deposits of mineral salts were also observed. Rare cases of an intranasal tooth associated with a rhinolith have been described in the literature. We believe that this case represents only the second published report of an intranasal tooth associated with a rhinolith in a patient with cleft lip and palate

Role of CCR2 in orthodontic tooth movement

Introduction: Cytokines and chemokines regulate bone remodeling during orthodontic tooth movement. CC chemokine ligand 2 (CCL2) is involved in osteoclast recruitment and activity, and its expression is increased in periodontal tissues under mechanical loading. In this study, we investigated whether the CC chemokine receptor 2 (CCR2)-CCL2 axis influences orthodontic tooth movement. Methods: A coil spring was placed in CCR2-deficient (CCR2(-/-)), wild-type, vehicle-treated, and P8A-treated (CCL2 analog) mice. In a histopathologic analysis, the amounts of orthodontic tooth movement and numbers of osteoclasts were determined. The expression of mediators involved in bone remodeling was evaluated by real-time polymerase chain reaction. Results: Orthodontic tooth movement and the number of TRAP-positive cells were significantly decreased in CCR2(-/-) and P8A-treated mice in relation to wild-type and vehicle-treated mice, respectively. The expressions of RANKL, RANK, and osteoblasts markers (COL-1 and OCN) were lower in CCR2(-/-) than in wild-type mice. No significant difference was found in osteoprotegerin levels between the groups. Conclusions: These data suggested a reduction of osteoclast and osteoblast activities in the absence of CCR2. The CCR2-CCL2 axis is positively associated with osteoclast recruitment, bone resorption, and orthodontic tooth movement. Therefore, blockage of the CCR2-CCL2 axis might be used in the future for modulating the extent of orthodontic tooth movement. (Am J Orthod Dentofacial Orthop 2012;141:153-60)

The influence of "C-factor" and light activation technique on polymerization contraction forces of resin composite

Objectives: This study evaluated the influence of the cavity configuration factor ("C-Factor") and light activation technique on polymerization contraction forces of a Bis-GMA-based composite resin (Charisma, Heraeus Kulzer). Material and Methods: Three different pairs of steel moving bases were connected to a universal testing machine (Emic DL 500): groups A and B - 2x2 mm (CF=0.33), groups C and D - 3x2 mm (CF=0.66), groups E and F - 6x2 mm (CF=1.5). After adjustment of the height between the pair of bases so that the resin had a volume of 12 mm(3) in all groups, the material was inserted and polymerized by two different methods: pulse delay (100 mW/cm(2) for 5 s, 40 s interval, 600 mW/cm(2) for 20 s) and continuous pulse (600 mW/cm(2) for 20 s). Each configuration was light cured with both techniques. Tensions generated during polymerization were recorded by 120 s. The values were expressed in curves (Force(N) x Time(s)) and averages compared by statistical analysis (ANOVA and Tukey's test, p<0.05). Results: For the 2x2 and 3x2 bases, with a reduced C-Factor, significant differences were found between the light curing methods. For 6x2 base, with high C-Factor, the light curing method did not influence the contraction forces of the composite resin. Conclusions: Pulse delay technique can determine less stress on tooth/restoration interface of adhesive restorations only when a reduced C-Factor is present.

Amino acids in squamous cell carcinomas and adjacent normal tissues from patients with larynx and oral cavity lesions

Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)

Finite element analysis of bonded model Class I 'restorations' after shrinkage

Objectives. The C-Factor has been used widely to rationalize the changes in shrinkage stress occurring at the tooth/resin-composite interfaces. Experimentally, such stresses have been measured in a uniaxial direction between opposed parallel walls. The situation of adjoining cavity walls has been neglected. The aim was to investigate the hypothesis that: within stylized model rectangular cavities of constant volume and wall thickness, the interfacial shrinkage-stress at the adjoining cavity walls increases steadily as the C-Factor increases. Methods. Eight 3D-FEM restored Class I 'rectangular cavity' models were created by MSC.PATRAN/MSC.Marc, r2-2005 and subjected to 1% of shrinkage, while maintaining constant both the volume (20 mm(3)) and the wall thickness (2 mm), but varying the C-Factor (1.9-13.5). An adhesive contact between the composite and the teeth was incorporated. Polymerization shrinkage was simulated by analogy with thermal contraction. Principal stresses and strains were calculated. Peak values of maximum principal (MP) and maximum shear (MS) stresses from the different walls were displayed graphically as a function of C-Factor. The stress-peak association with C-Factor was evaluated by the Pearson correlation between the stress peak and the C-Factor. Results. The hypothesis was rejected: there was no clear increase of stress-peaks with C-Factor. The stress-peaks particularly expressed as MP and MS varied only slightly with increasing C-Factor. Lower stress-peaks were present at the pulpal floor in comparison to the stress at the axial walls. In general, MP and MS were similar when the axial wall dimensions were similar. The Pearson coefficient only expressed associations for the maximum principal stress at the ZX wall and the Z axis. Significance. Increase of the C-Factor did not lead to increase of the calculated stress-peaks in model rectangular Class I cavity walls. (C) 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Effectiveness of Tooth Wipes in Removing Babies' Dental Biofilm

Purpose: To assess the effectiveness of tooth wipes in removing dental biofilm from babies' anterior teeth, as well as to evaluate the babies' behaviour and the guardians' preference concerning hygiene methods. Materials and Methods: In this random blind cross-over study, 50 high caries risk babies, from 8 to 15 months old, were divided into two groups: babies with oral hygiene performed by caregivers (n = 25) or by their mothers (n = 25). The caregivers and mothers removed biofilm using three methods of oral hygiene (tooth wipes, toothbrushes and gauze), one in each experimental phase. Professional cleaning was done before each phase, which had 2 days of biofilm accumulation and 1 experimental day, when caregivers and mothers used one method to remove biofilnn. Examiners blinded to the study design assessed the biofilm index at baseline, prior to and following biofilm removal using each method. The babies' behaviour and the mothers'/caregivers' preference were assessed. Results: The tooth wipes, toothbrushes and gauze significantly reduced the amount of biofilm (P < 0.001). The mothers' group removed more biofilm than the caregivers' group, using toothbrushes or tooth wipes (P < 0.05). Babies in the mothers' group had better behaviour using tooth wipes than toothbrushes (P < 0.05). Mothers and caregivers preferred to use tooth wipes. Conclusions: Tooth wipes are effective in removing biofilrn from babies' anterior teeth and are the method best accepted by mothers, caregivers and babies.

Retrospective Clinical Study of 988 Dual Acid-Etched Implants Placed in Grafted and Native Bone for Single-Tooth Replacement

Purpose: To evaluate the influence of sex, implant characteristics, and bone grafting on the survival rate of dual acid-etched (DAE) implants. Materials and Methods: Patients treated with internal-hex DAE implants for single-tooth replacement in a military dental clinic between January 2005 and December 2010 were included in this study. Clinical data related to implant characteristics, implant location, presence of grafted bone, and implant failures were collected. The primary outcome was implant loss. The survival rate was analyzed using the Kaplan-Meier method. Cox regression modeling was used to determine which factors would predict implant failure. Results: DAE implants were evaluated in a total of 988 patients (80.3% men). Twenty-four (2.4%) implants failed, most were cylindric (54.2%) with regular platforms (70.8%) and were 10 mm long (58.3%). The failure rate was 2.4% for the anterior maxilla, 3.3% for the posterior maxilla, 1.6% for the anterior mandible, and 2.0% for posterior mandible. The cumulative survival rate was 97.6%. The failure rate was 8.8% in implants placed after sinus augmentation, 7.3% in bone block-grafted areas, and 1.6% in native bone. Based on multivariable analysis (Cox regression), sinus augmentation and bone block grafting had a statistically significant effect on implant failure; the hazard ratios were 5.5 and 4.6, respectively. Conclusion: The results revealed that DAE implants had high survival rates, and no influence of sex, location, shape, diameter, or length on failure rates could be observed. However, a significant association was observed between failure and presence of bone graft in the implant area. Int J Oral Maxillofac Implants 2012;27:1243-1248

What is Missing for Traditional Design-Centric Engineering Education to Better Prepare Newly Graduated Engineers for the Global Era?

This paper presents an analysis of the capacity of design centric methodologies to prepare engineering students to succeed in the market. Gaps are brainstormed and analyzed with reference to their importance. Reasons that may lead the newly graduated engineers not to succeed right from the beginning of their professional lives have also been evaluated. A comparison among the two subjects above was prepared, reviewed and analyzed. The influence of multidisciplinary, multicultural and complex environmental influences created in the current global business era is taken into account. The industry requirements in terms of what they expect to 'receive' from their engineers are evaluated and compared to the remaining of the study above. An innovative approach to current engineering education that utilizes traditional design-centric methodologies is then proposed, aggregating new disciplines to supplement the traditional engineering education. The solution encompasses the inclusion of disciplines from Human Sciences and Emotional Intelligence fields willing to better prepare the engineer of tomorrow to work in a multidisciplinary, globalized, complex and team working environment. A pilot implementation of such an approach is reviewed and conclusions are drawn from this educational project.

Influence of prior 810-nm-diode intracanal laser irradiation on hydrophilic resin-based sealer obturation

Dentin wall structural changes caused by 810-nm-diode laser irradiation can influence the sealing ability of endodontic sealers. The objective of this study was to evaluate the apical leakage of AH Plus and RealSeal resin-based sealers with and without prior diode laser irradiation. Fifty-two single-rooted mandibular premolars were prepared and divided into 4 groups, according to the endodontic sealer used and the use or non-use of laser irradiation. The protocol for laser irradiation was 2.5W, continuous wave in scanning mode, with 4 exposures per tooth. After sample preparation, apical leakage of 50% ammoniacal silver nitrate impregnation was analyzed. When the teeth were not exposed to irradiation, the Real Seal sealer achieved the highest scores, showing the least leakage, with significant differences at the 5% level (Kruskal-Wallis test, p = 0.0004), compared with AH Plus. When the teeth were exposed to the 810-nm-diode laser irradiation, the sealing ability of AH Plus sealer was improved (p = 0282). In the Real Seal groups, the intracanal laser irradiation did not interfere with the leakage index, showing similar results in the GRS and GRSd groups (p = 0.1009).

Ni/Pd@MIL-101: Synergistic Catalysis with Cavity-Conform Ni/Pd Nanoparticles

Deutsche Forschungsgemeinschaft [SFB 840]

Revisiting a medical case of "stinging" in the human oral cavity caused by ingestion of raw squid (Cephalopoda: Teuthida): new data on the functioning of squid's spermatophores

Male squid produce intricate spermatophores that, when transferred to the female, undergo the spermatophoric reaction, a complex process of evagination that leads to the attachment of the spermatangium, that is, the everted spermatophore containing the sperm mass. While this process is still not completely understood, the medical literature includes several reports of "oral stinging" (i.e., punctured wounds in the human oral cavity) following consumption of raw male squid, which contains undischarged spermatophores able to inflict such wounds. Here, we revisit a recent medical report of oral stinging by Shiraki et al. (Pathol Int 61:749-751, 2011), providing an in-depth reanalysis of their histological biopsies and revealing vital information on the functioning of squid spermatophores. The morphology of the spermatangia attached within the oral cavity is similar to the condition found in spermatangia naturally attached to female squids. The spermatangia were able to superficially puncture the superficial layers of the oral stratified squamous epithelium, and numerous, minute stellate particles from the squid spermatophore were found adhered to the oral epithelium. These findings corroborate previous hypotheses on the functioning of squid spermatophores, namely that spermatophore attachment generally involves tissue scarification, and that stellate particles play a vital role in the attachment process. Moreover, spermatophore attachment is confirmed to be autonomous (i.e., performed by the spermatophore itself) in another squid species (possibly a loliginid), and the results strongly indicate that the attachment mechanism is not dependent upon a specialized epithelium, nor a mate's specific chemical stimulus. From the pathological point of view, the best prophylactic measure at present is the removal of the internal organs of the raw squid prior to its consumption.

Multiple Tooth Agenesis in Non-syndromic Patient: a rare case report

Dental agenesis is a term referred to the absence of one or more teeth. However, oligodontia is a severe type of tooth agenesis involving six or more congenitally missing teeth, excluding the third molars. Oligodontia has a low prevalence and is a very rare condition. The aim was to show this case report of a 13-year-old female patient who presented oligodontia with absence of eight permanent teeth and condylar atrophy on left side. The patient had no history of any syndrome or systemic disease according to the anamnesis. Is very important to know oligodontia features to perform a carefully treatment plan.

Celecoxib treatment does not alter recruitment and activation of osteoclasts in the initial phase of experimental tooth movement

In a previous study, we reported that the short-term treatment with celecoxib, a nonsteroidal anti-inflammatory drug (NSAID) attenuates the activation of brain structures related to nociception and does not interfere with orthodontic incisor separation in rats. The conclusion was that celecoxib could possibly be prescribed for pain in orthodontic patients. However, we did not analyze the effects of this drug in periodontium. The aim of this follow-up study was to analyze effects of celecoxib treatment on recruitment and activation of osteoclasts and alveolar bone resorption after inserting an activated orthodontic appliance between the incisors in our rat model. Twenty rats (400420 g) were pretreated through oral gavage with celecoxib (50 mg/kg) or vehicle (carboxymethylcellulose 0.4%). After 30 min, they received an activated (30 g) orthodontic appliance, set not to cause any palate disjunction. In sham animals, the appliance was immediately removed after introduction. All animals received ground food and, every 12 h, celecoxib or vehicle. After 48 h, they were anesthetized and transcardiacally perfused through the aorta with 4% formaldehyde. Subsequently, maxillae were removed, post-fixed and processed for histomorphometry or immunohistochemical analyses. As expected, incisor distalization induced an inflammatory response with certain histological changes, including an increase in the number of active osteoclasts at the compression side in group treated with vehicle (appliance: 32.2 +/- 2.49 vs sham: 4.8 +/- 1.79, P<0.05) and celecoxib (appliance: 31.0 +/- 1.45 vs sham: 4.6 +/- 1.82, P<0.05). The treatment with celecoxib did not modify substantially the histological alterations and the number of active osteoclasts after activation of orthodontic appliance. Moreover, we did not see any difference between the groups with respect to percentage of bone resorption area. Taken together with our previous results we conclude that short-term treatment with celecoxib can indeed be a therapeutic alternative for pain relieve during orthodontic procedures.

Mini-implant insertion based on tooth crown references: a guide-free technique

Mini-implant insertion requires accurate surgical technique. This study shows an insertion technique using only tooth crown references; its scientific basis is evaluated radiographically. The sample consisted of 213 inter-radicular septa, evaluated in 53 bitewing radiographs. The proximal contour of adjacent tooth crowns was used to define septum width. The midpoint of the septum width was linked to the interdental contact point to determine septum midline. The distances from septum midline to "mesial and distal teeth were measured to evaluate the septum midline centralization degree in two different septum heights. The difference between mesial and distal distances represented the septum midline deviation degree. The mesial and distal distances were compared by t-tests, and the septum midline deviation was correlated with septum height using Pearson's correlation test. The mesial and distal distances were not statistically different in the midpoint of the septum height, but they were different at the apical septum height. There was a moderate correlation (r = 0.45) between septum midline deviation and septum height. The tooth crown references evaluated on interproximal radiographs determine a high centralization degree of the septum midline on which the insertion site could be defined. The greater centralization degree was observed at the coronal septum area.