Longevity of bond strength of resin cements to root dentine after radiation therapy.

AIM: To evaluate the bond strength and adhesive interface between several resin cements and root dentine immediately and 6 months after radiotherapy. METHODOLOGY: Sixty maxillary canines were selected and randomly assigned to two groups (n = 30): one group was not irradiated and the other one was subjected to a cumulative radiation dose of 60 Gy. The teeth were sectioned to obtain roots 16 mm long and the canals were prepared with the Reciproc system (R50) and filled using a lateral condensation technique with an epoxy resin sealer. Each group was divided into three subgroups (n = 10) according to the resin cement used for fibreglass fibre post cementation: RelyX-U200, Panavia-F2.0 and RelyX ARC. The posts were cemented in accordance with the manufacturer's recommendations. Three 1-mm-thick dentine slices were then obtained from each root third. The first two slices in the crown-apex direction of each third were selected for the push-out test. The failure mode after debonding was determined with a stereo microscope. The third slice from each root third was selected for scanning electron microscopy (SEM) analyses to examine the resin cement-dentine interface with 100, 1000, 2000 and 4000× magnification. Bond strength data were analysed by anova and Tukey's test (α = 0.05). RESULTS: Significantly lower bond strength (P < 0.0001) was obtained after irradiation compared to nonirradiated teeth. RelyX-U200 cemented fibre posts had the higher bond strength (15.17 ± 5.89) compared with RelyX ARC (P < 0.001) and Panavia-F2.0 (P < 0.001). The evaluation after 6 months revealed lower bond strength values compared to the immediate values (P < 0.001) for irradiated and nonirradiated teeth. Cohesive failures occurred in the irradiated dentine. SEM revealed fractures, microfractures and fewer collagen fibres in irradiated root dentine. RelyX-U200 and Panavia-F2.0 were associated with a juxtaposed interface of the cement with the radicular dentine in irradiated and nonirradiated teeth, and for RelyX ARC, hybrid layer formation and tags were observed in both irradiated and nonirradiated teeth. CONCLUSION: Radiation was associated with a decrease in the push-out bond strength and with lower resin cement/root dentine interface adaptation. Self-adhesive resin cement was a better alternative for fibre post cementation in teeth subjected to radiation therapy. The bond strength decreased after 6 months.

Enamel pearls in permanent dentition: case report and micro-CT evaluation.

OBJECTIVES: To investigate the frequency, position, number and morphology of enamel pearls (EPs) using micro-CT (µCT) and to report a case of an EP mimicking an endodontic-periodontic lesion. METHODS: Cone beam CT (CBCT) was performed in a patient to evaluate a radio-opaque nodule observed on the left maxillary first molar during the radiographic examination. Additionally, 23 EPs were evaluated regarding frequency, position, number and morphology by means of µCT. The results were statistically compared using the Student's t-test for independent samples. RESULTS: 1 pearl was presented in 13 specimens, while 5 specimens presented 2 pearls. The most frequent location of the EPs was the furcation between the disto-buccal and the palatal roots of the maxillary molars. Overall, the mean major diameter, volume and surface area were 1.98 ± 0.85 mm, 1.76 ± 1.36 mm³ and 11.40 ± 7.59 mm², respectively, with no statistical difference between maxillary second and third molars (p > 0.05). In the case report, CBCT revealed an EP between the disto-buccal and the palatal roots of the maxillary first left molar associated with advanced localized periodontitis. The tooth was referred for extraction. CONCLUSIONS: EPs, located generally in the furcation area, were observed in 0.74% of the sample. The majority was an enamel-dentin pearl type and no difference was found in maxillary second and third molars regarding diameter, volume and surface area of the pearls. In this report, the EP mimicked an endodontic-periodontic lesion and was a secondary aetiological factor in the periodontal breakdown.

Effect of Er:YAG laser and EDTAC on the adhesiveness to dentine of different sealers containing calcium hydroxide.

AIM: To evaluate the effect of 15% EDTAC solution and Er:YAG laser irradiation on the adhesiveness to dentine of root canal sealers containing calcium hydroxide. METHODOLOGY: The crowns of 60 maxillary human molars were ground until dentine was exposed. The teeth were divided into three groups of 20 teeth: group I, the dentine surface received no treatment; group II, 15% EDTAC solution was applied to the dentine; group III, the dentine received Er:YAG laser application (11 mm focal distance with perpendicular incidence to dentine surface; 4 Hz frequency; 200 mJ energy; 2.25 W potency; 62 J total energy; 1 min application time). Aluminium cylinders filled with the sealers, Sealer 26, Apexit, Sealapex and CRCS, were then applied to the treated surfaces. Adhesiveness was measured with a universal testing machine, with traction results given in MegaPascals (MPa). These results were submitted to anova tests. RESULTS: Statistical analysis showed significant differences (P < 0.01) amongst adhesiveness values of the sealers and treatments tested. Thus, sealers could be ranked in decreasing adhesiveness values: Sealer 26, CRCS, Apexit, Sealapex. Er:YAG laser irradiation and EDTAC solution application increased adhesiveness values only for Sealer 26 and Apexit. Laser irradiation was superior to EDTAC application only for Sealer 26 adhesiveness values. CONCLUSIONS: Er:YAG laser is as efficient as EDTAC solution in increasing adhesiveness of root canal sealers containing calcium hydroxide to human dentine.

Adhesion of a glass-ionomer root canal sealer to human dentine.

This in vitro study evaluated the effect of smear layer removal on adhesion to human dentine of Ketac-Endo, Grossman, and Sealer 26 root canal sealers. A total of 60 extracted human maxillary and mandibular molars with their crowns ground flat were used. The teeth were divided into two groups: Group 1, the dentine surface received no treatment; Group 2, EDTA-C was applied to the dentine surface for 5 min. Ten samples were tested for each sealer and each group. Adhesion was measured with a Universal Testing Machine. Sealer 26 showed greater adhesion both with and without smear layer (p < 0.01). Ketac-Endo and Grossman sealers were statistically equal, having the lowest values of adhesion. Application of EDTA-C did not alter the adhesion of Ketac-Endo and Grossman sealers. However, the use of EDTA-C increased the adhesion of Sealer 26. The epoxy resin-based root canal sealer (Sealer 26) adhered better to dentine prepared with and without EDTA-C than glass-ionomer-based sealers and the zinc oxide eugenol-based (Ketac-Endo and Grossman) sealers.

Clinical aspects of pulpal-periodontal lesions.

It is well known that the main purpose of dentistry is to keep teeth in the oral cavity so that they may fulfill their various roles. This case report demonstrates a method to treat a situation involving a pulpal-periodontal lesion, by using a simple and efficient combined therapy. The clinician can thereby determine the cause of the lesion (pulpal and/or periodontal) and subsequently establish the correct treatment, thus improving the prognosis of the case.

Evaluation of the effect of EDTAC, CDTA, and EGTA on radicular dentin microhardness.

The effect of EDTAC (ethylenediamine tetra-acetic acid plus Cetavion, an ammonium surfactant), CDTA (cyclohexane-1,2-diaminetetra-acetic acid), and EGTA (ethylene glycol-bis-(beta-amino-ethyl ether) N,N,N',N'-tetra-acetic acid) on the microhardness of radicular dentin of the cervical third of human teeth was studied. Five newly extracted maxillary incisors were sectioned transversely at the cementoenamel junction, and the crowns were discarded. The roots were embedded in blocks of high-speed polymerized acrylic resin and cut transversely into 1-mm sections. The second slice of the cervical third of the root of each tooth was sectioned and divided into four parts. Each part was placed on an acrylic disc that was used as a base for microhardness measurement. Fifty microliters of 15% EDTAC, 1% CDTA, or 1% EGTA were applied to the dentin surface. Deionized and distilled water was used as control. Dentin microhardness was then measured with a Vicker's microhardness apparatus with a load of 50 g for 15 s. Statistical analysis showed that the three chelating solutions significantly reduced dentin microhardness when compared with water; however, there was no statistically significant difference among the three solutions.

Dental anomaly: dens evaginatus (talon cusp).

Dens evaginatus is a developmental anomaly characterized by the occurrence of an extra cusp shaped as a tubercle projecting from the palatal or buccal surfaces (talon cusp). In the anterior dentition, dens evaginatus is more commonly found in the maxilla and on the palatal surface of the tooth. The authors present a case of dens evaginatus in a maxillary central incisor, in which the evagination was removed and routine endodontic treatment was performed.

Treatment of middle-apical level root fracture in necrotic teeth.

The purpose of this paper is to present two case reports of dental trauma with middle-apical level root fractures and pulp necrosis. The treatment consisted of programmed applications of calcium hydroxide until a calcified barrier was formed at the fracture level. The technique presented here proved efficient in treating horizontal fractures at the middle and apical thirds of the root.

Effect of different grades of gum rosins and hydrogenated resins on the solubility, disintegration, and dimensional alterations of Grossman cement.

In the present study, we investigated the effect of the addition of different grades of gum rosins and hydrogenated resins to Grossman cement on dimensional stability, solubility and disintegration. pH and conductivity, which may affect these properties, were also determined. The experiments were performed according to Specification 57 of the American Dental Association for root canal cements using Grossman cements containing three gum rosins (grades X, WW, and WG) and two hydrogenated resins (Staybelite and Staybelite ester 10). The results showed that the solubility, disintegration, and dimensional stability of Grossman cement containing Staybelite and Staybelite ester 10 were inferior to the values considered acceptable by the American Dental Association Specification 57.

Periapical cemental dysplasia: case report.

The authors present a case of periapical cemental dysplasia affecting the mandibular left canine, with vital pulp, in a 43-year-old black female patient, an occurrence that follows the classical cases found in the literature. The need of a careful history, clinical and radiographic exams and vitality tests are emphasized in order to reach the correct diagnosis of this disease.

The influence of different grades of rosins and hydrogenated resins on the powder-liquid ratio of Grossman cements.

In this study, the effect of different grades of rosin and hydrogenated resin on the setting time of Grossman cement was evaluated. The experiments were carried following the American Dental Association Specification number 57 for root canal sealers. For this analysis, different Grossman cement powders were prepared using different grades of rosin (X,WW and WG) and hydrogenated resin (Staybelite and Staybelite ester 10). The pH and electrical conductance of the different grades of rosin and hydrogenated resin were evaluated. The physicochemical properties of the Grossman cements obtained with the different grades of rosin and hydrogenated resins interfere in the powder-liquid ratio of the cements. The sealers obtained with the hydrogenated resin showed a higher powder-liquid ratio.

Treatment of dens invaginatus in supernumerary teeth.

The endodontic treatment and aesthetic restoration of a case of Oehlers Type I dens invaginatus in supernumerary teeth is presented.

Root canal therapy of an anomalous maxillary central incisor: a case report.

A case of endodontic conservative treatment of a maxillary central incisor with an atypical crown and Type III dens invaginatus is presented. The greatest difficulty was to locate the root canals due to the atypical internal anatomy. There were not two clear canals, but the coronal pulp chamber showed two entrances to the root canal. The tooth presented a distal periodontal pocket and various lingual radicular grooves. The appearance of the crown was improved by alteration of its dimension using diamond rotary instruments and correction with photopolymerized resin.

In vitro study of root canal anatomy of maxillary second premolars.

The external anatomy of 435 maxillary second premolars and the internal anatomy of 300 of these premolars were studied in vitro. For the study of the internal anatomy, the teeth were decalcified and cleared. One canal was found in 67.3% of the second premolars, two canals in 32.4% and three canals in 0.3% of these premolars. A total of 90.3% had one root and 9.7% two roots. A predominance of root curvature toward the distal was found in maxillary second premolars with both one or two roots.

Internal anatomy, direction and number of roots and size of human mandibular canines.

The internal anatomy, direction and number of roots and size were studied on 830 extracted human mandibular canines. The internal anatomy was studied using the methyl salicylate clearing method, which showed that 98.3% of these teeth presented a single root, with 92.2% presenting one canal and one foramen, 4.9% with two canals and one foramen, and 1.2% with two canals and two foramina. The incidence of two-rooted canines was low, 1.7%. As to direction of the roots, 51% were straight, 14.6% presented mesial, 25.5% distal, 1.0% lingual, 3.2% buccal, and 4.4% sigmoid curvatures. The mean length of the teeth was 25.5 mm, ranging from 20.3 mm to 32.8 mm.

Root form and canal anatomy of maxillary first premolars.

The external and internal anatomy of 240 extracted, maxillary first premolars was studied. The external anatomy was studied by measuring each tooth and by observing the direction of the root curvatures from the facial and proximal aspects. The internal anatomy of the pulp cavity was studied by a method of making the teeth translucent. A total of 55.8% of the teeth had a single root, 41.7% had two roots and 2.5% had three roots. Considering all of the first premolars, 17.1% had one canal, 80.4% had two canals and 2.5% had three canals.

Endodontic treatment of a maxillary lateral incisor presenting dens invaginatus and transposition to the region of the canine--case report.

Endodontic treatment was performed in a maxillary lateral incisor presenting two different types of anomalies: dens invaginatus and transposition to the region of the canine. The two transposed teeth were subsequently restored with light-cured composite, bringing dental esthetics to normal in a single session.

In vitro study of the incidence of radicular grooves in maxillary incisors.

The purpose of this investigation was to determine the prevalence of radicular grooves in 500 central and 421 lateral extracted maxillary incisors. Radicular grooves were present in 2.0% of the central and 2.6% of the lateral maxillary incisors. The majority of radicular grooves in central maxillary incisors were detected on the buccal root surface (1.6%), and fewer on the lingual root surface (0.4%). In lateral maxillary incisors, the radicular grooves were always observed on the lingual surface.