Carolina Paes Torres

Microstructure and mineral composition of dental enamel of permanent and deciduous teeth

Purpose: This study evaluated and compared in vitro the microstructure and mineral composition of permanent and deciduous teeths dental enamel. Methods: Sound third molars (n = 12) and second primary molars (n = 12) were selected and randomly assigned to the following groups, according to the analysis method performed (n = 4): Scanning electron microscopy (SEM), X‐Ray diffraction (XRD) and Energy dispersive X‐ray spectrometer (EDS). Qualitative and quantitative comparisons of the dental enamel were done. The microscopic findings were analyzed statistically by a nonparametric test (Kruskal‐Wallis). The measurements of the prisms number and thickness were done in SEM photomicrographs. The relative amounts of calcium (Ca) and phosphorus (P) were determined by EDS investigation. Chemical phases present in both types of teeth were observed by the XRD analysis. Results: The mean thickness measurements observed in the deciduous teeth enamel was 1.14 mm and in the permanent teeth enamel was 2.58 mm. The mean rod head diameter in deciduous teeth was statistically similar to that of permanent teeth enamel, and a slightly decrease from the outer enamel surface to the region next to the enamel‐dentine junction was assessed. The numerical density of enamel rods was higher in the deciduous teeth, mainly near EDJ, that showed statistically significant difference. The percentage of Ca and P was higher in the permanent teeth enamel. Conclusions: The primary enamel structure showed a lower level of Ca and P, thinner thickness and higher numerical density of rods. Microsc. Res. Tech., 2010.

Surface and subsurface erosion of primary enamel by acid beverages over time

This study evaluated the influence of a cola-type soft drink and a soy-based orange juice on the surface and subsurface erosion of primary enamel, as a function of the exposure time. Seventy-five primary incisors were divided for microhardness test (n=45) or scanning electron microscopy (SEM) analysis (n=30). The specimens were randomly assigned to 3 groups: 1 - artificial saliva (control); 2 - cola-type soft drink; and 3 - soy-based orange juice. Immersion cycles in the beverages were undertaken under agitation for 5 min, 3 times a day, during 60 days. Surface microhardness was measured at 7, 15, 30, 45 and 60 days. After 60 days, specimens were bisected and subsurface microhardness was measured at 30, 60, 90, 120, 150 and 200 µm from the surface exposed. Data were analyzed by ANOVA and Tukeys test (a=0.05). Groups 2 and 3 presented similar decrease of surface microhardness. Regarding subsurface microhardness, group 2 presented the lowest values. SEM images revealed that after 60 days the surfaces clearly exhibited structural loss, unlike those immersed in artificial saliva. It may be concluded that erosion of the surfaces exposed to the cola-type soft drink was more accentuated and directly proportional to the exposure time.

Bond strength of a pit-and-fissure sealant associated to etch-and-rinse and self-etching adhesive systems to saliva-contaminated enamel: individual vs. simultaneous light curing

This study evaluated in vitro the shear bond strength (SBS) of a resin-based pit-and-fissure sealant [Fluroshield (F), Dentsply/Caulk] associated with either an etch-and-rinse [Adper Single Bond 2 (SB), 3M/ESPE] or a self-etching adhesive system [Clearfil S3 Bond (S3), Kuraray Co., Ltd.] to saliva-contaminated enamel, comparing two curing protocols: individual light curing of the adhesive system and the sealant or simultaneous curing of both materials. Mesial and distal enamel surfaces from 45 sound third molars were randomly assigned to 6 groups (n=15), according to the bonding technique: I - F was applied to 37% phosphoric acid etched enamel. The other groups were contaminated with fresh human saliva (0.01 mL; 10 s) after acid etching: II - SB and F were light cured separately; III - SB and F were light cured together; IV - S3 and F were light cured separately; V - S3 and F were light cured simultaneously; VI - F was applied to saliva-contaminated, acid-etched enamel without an intermediate bonding agent layer. SBS was tested to failure in a universal testing machine at 0.5 mm/min. Data were analyzed by one-way ANOVA and Fishers test (alpha=0.05).The debonded specimens were examined with a stereomicroscope to assess the failure modes. Three representative specimens from each group were observed under scanning electron microscopy for a qualitative analysis. Mean SBS in MPa were: I-12.28 (+/-4.29); II-8.57 (+/-3.19); III-7.97 (+/-2.16); IV-12.56 (+/-3.11); V-11.45 (+/-3.77); and VI-7.47 (+/-1.99). In conclusion, individual or simultaneous curing of the intermediate bonding agent layer and the resin sealant did not seem to affect bond strength to saliva-contaminated enamel. S3/F presented significantly higher SBS than the that of the groups treated with SB etch-and-rinse adhesive system and similar SBS to that of the control group, in which the sealant was applied under ideal dry, noncontaminated conditions.

Dental care management in a child with recessive dystrophic epidermolysis bullosa

Epidermolysis bullosa (EB) is a heterogeneous group of rare genetic disorders characterized by marked fragility of the skin and mucous membranes in which vesiculobullous lesions occur in response to trauma, heat or no apparent cause. The recessive form of EB presents the greatest oral alterations including repeated blistering and scar formation leading to limited oral opening, ankyloglossia, tongue denudation, microstomia, vestibule obliteration and predisposition to oral carcinoma. Routine dental care may cause bullae formation on the lips and oral mucosa. Together with the ingestion of soft and frequently carbohydrate food, these anomalies lead to a high caries risk. This paper documents a case of a child diagnosed with recessive dystrophic epidermolysis bullosa (RDEB); describes the phases and difficulties of dental treatment and the measures that dentists and health care providers should adopt in order to provide a safe and effective dental treatment as well as earlier prevention to these patients.

Effect of Er:YAG Laser Parameters on Ablation Capacity and Morphology of Primary Enamel

OBJECTIVE The purpose of this study was to evaluate the ablation capacity of different energies and pulse repetition rates of Er:YAG laser energy on primary molar enamel, by assessing mass loss and by analyzing the surface morphology with scanning electron microscopy. BACKGROUND DATA Previous studies have demonstrated the capacity of the Er:YAG laser to ablate enamel substrate. METHODS Forty-two sound primary molars were bisected in a mesiodistal direction. The enamel surfaces were flattened and their initial mass (in milligrams) was obtained. An area of 4 mm(2) was delimited. The specimens were randomly assigned to 12 groups according to the combination of energy (160, 200, 250, and 300 mJ) and pulse repetition rate (2, 3, and 4 Hz). Er:YAG laser irradiation was performed on each specimen for 20 sec. After irradiation, the final mass was obtained and specimens were prepared for examination with scanning electron microscopy. The data obtained by subtracting the final mass from the initial mass were statistically analyzed using ANOVA and the Tukey test (p < 0.05). RESULTS The pulse repetition rate of 4 Hz provided greater mass loss, different from that seen with 2 Hz, and similar to that seen with 3 Hz. The energy level of 300 mJ resulted in greater mass loss, similar to that seen with 200 and 250 mJ. Scanning electron photomicrographs showed that there was non-selective enamel removal, with fused and cracked areas in all specimens. CONCLUSION The parameters of 200 mJ and 2 Hz produced a good ablation rate with fewer surface alterations in primary molar enamel.

Effect of laser acupuncture and auricular acupressure in a child with trismus as a sequela of medulloblastoma

In several countries the most common cause of death in young people is cancer. Patients with head and neck cancer often have complications after cancer treatment. Radiation therapy can cause oral trismus, which is related to high doses of radiation. Although acupuncture is reported to be effective and is widely used for the treatment of peripheral facial paralysis by promoting an improvement of motor functions, few reports in the literature demonstrate its effectiveness. We report a case in which the symptoms of a patient with facial paralysis after surgical cancer treatment associated with chemotherapy and radiotherapy improved after laser treatment at acupuncture points. Ten weekly sessions of laser therapy were conducted, using the Twin laser device, applied to systemic acupuncture points (LR3, LI4, LI18, LI19, LI20, SI17, SI19, ST4, ST6, ST7, GV20), together with 10 weekly sessions of auricular acupressure. Significant improvement of the trismus was seen, confirmed by the increase in mouth opening from 33.26 to 53.3 mm. The patients family also noted reduced anxiety and hyperactivity. These results suggest that laser acupuncture and auricular acupressure for trismus and facial paralysis following cancer treatment is worth further investigation.

Effect of Erbium-Doped Yttrium Aluminium Garnet Laser Parameters on Ablation Capacity and Morphology of Primary Dentin

OBJECTIVE To evaluate the ablation capacity of different energies and pulse repetition rates of an erbium-doped yttrium aluminium garnet (Er:YAG) laser on primary dentin by assessing mass loss and to analyze the surface morphology using scanning electron microscopy (SEM). BACKGROUND DATA Previous studies have demonstrated the ability of the Er:YAG laser to ablate dentin substrate. METHODS Forty-eight sound primary molars were bisected in the mesiodistal direction. The dentin surfaces were flattened, and initial mass (mg) was obtained. A 4-mm2 area was delimited. Specimens were randomly assigned to 12 groups according to the combination of energy (160, 200, 250, and 300 mJ) and pulse repetition rate (2, 3, and 4 Hz). Er:YAG laser irradiation was performed for 20 s. After irradiation, the final mass was obtained, and specimens were prepared for SEM. The data obtained by subtracting the final mass from the initial mass were statistically analyzed using analysis of variance and Tukey test (alpha=0.05). RESULTS The pulse repetition rate of 4 Hz provided greater mass loss, and it was different from 2 Hz and 3 HZ. The energy of 300 mJ resulted in greater mass loss, similar to 200 and 160 mJ. SEM micrographs showed dentinal tubule obliteration, structural alterations, and the presence of cracked areas in all specimens. CONCLUSION The settings of 160, 200, and 250 mJ at 2 and 3 Hz promoted a good ablation rate with fewer surface alterations in primary dentin.

Dental findings in Kabuki make-up syndrome: a case report.

This article documents the case history of a 9-year-old Brazilian child diagnosed with Kabuki make-up syndrome (KMS). The clinical features are described, with emphasis on the craniofacial and orodental manifestations. The patient had the distinctive KMS craniofacial features consisting of long palpebral fissure, hypertelorism, high-arched eyebrows with sparse hair in the lateral one-third, eyes with eversion of the lateral one-third of the lower eyelids, long and curved eyelashes, palpebral ptosis, large anteverted prominent ears in a lower position, broad, depressed nasal root with a flat nasal tip, and mild neuropsychomotor developmental deficits. The intraoral examination revealed an anterior open bite, overretention of primary teeth, and a high-arched palate. Two findings in this child have not been previously reported in patients with KMS: the presence of supernumerary teeth and taurodontic teeth in the maxillary arch. The clinical and radiographic detection of these unique dental features may be helpful in identifying children who may have milder forms of KMS.

Self-etch bonding agent beneath sealant: Bond strength for laser-irradiated enamel

Objectives: This study evaluated the in vitro shear bond strength (SBS) of a resin-based pit-and-fissure sealant (Fluroshield [F], Dentsply/Caulk) associated with either an etch-and-rinse (Adper Single Bond 2 [SB], 3M/ESPE) or a two-step self-etch adhesive system (Adper SE Plus [SE], 3M/ESPE) on Er: YAG laser-irradiated enamel. Materials and Methods: Seventeen sound third molar crowns were embedded in acrylic resin, and the mesial-distal enamel surfaces were flattened. The enamel sites were irradiated with a 2.94-μm wavelength Er: YAG laser (120 mJ, 4 Hz, noncontact mode/17 mm, 20 s). The specimens were randomly assigned to three groups according to the bonding technique: I - 37% phosphoric acid etching + SB + F; II - SE + F and III - F applied to acid-etched enamel, without an intermediate layer of bonding agent. In all of the groups, a 3-mm diameter enamel-bonding site was demarcated and the sealant cylinders were bonded. After 24 hours in distilled water, the shear bond strength was tested at a crosshead speed of 0.5 mm/minute. The data were analyzed by one-way ANOVA and Tukey′s test. The debonded specimens were examined with a stereomicroscope to assess the failure modes. Results: The mean SBS values in MPa were I = 6.39 (±1.44); II = 9.50 (±2.79); and III = 5.26 (±1.82). No statistically significant differences were observed between groups I and III; SE/F presented a significantly higher SBS than that of the other groups (P = 0.001). With regard to the failure mode, groups I (65%) and II (75%) presented adhesive failures, while group III showed 50% adhesive failure. Cohesive failure did not occur. Conclusion: The application of the two-step self-etch bonding agent (Adper SE Plus) beneath the resin pit-and-fissure sealant placement resulted in a significantly higher bond strength for the Er:YAG laser-irradiated enamel.

Oral findings and dental treatment in a child with West syndrome

West syndrome (WS) is a rare, severe form of epilepsy that typically manifests early in infancy. It is considered a malignant condition that combines episodes of spasms that occur in clusters (infantile spasm), hypsarrhythmia on the electroencephalogram, and neuropsychomotor delay. Although WS has been widely investigated from a medical standpoint, few reports have focused on the oral findings in patients with this syndrome. This article reports the case history of a 7-year-old child diagnosed with WS. The major clinical features were generalized tooth wear and gingival enlargement, altered chronology and sequence of dental eruption, primary canine cusp-to-cusp relationship, ectopic dental eruption, and mildly arched palate. Multiple white spot lesions were also observed, possibly associated with poor oral hygiene, due to a fermentable carbohydrate-rich diet, and continuous use of sugar-containing medications. Dental care management of patients with special needs is discussed and the dental treatment for this child with WS is described.