Safety of laser use under the dental microscope

The aim of this study was to investigate the safety of laser use under the dental microscope. Nd:YAG, Er:YAG and diode lasers were used. The end of the tips was positioned at a distance of 5 cm from the objective lens of a dental microscope. Each eye protector was made into a flat disc, which was fixed on the lens of the microscope. The filters were placed in front of the objective lens or behind the eye lens. Transmitted energy through the microscope with or without the filters was measured. No transmitted laser energy was detected when using matched eye protectors. Mismatched eye protectors were not effective for shutting out laser energy, especially for Nd:YAG and diode lasers. None or very little laser energy was detected through the microscope even without any laser filter. Matched filters shut out all laser energy irrespective of their positions.     

In vitro comparison of different reciprocating systems used during endodontic retreatment

The present study evaluated the effectiveness of two reciprocating systems for the removal of root‐filling material during endodontic retreatment. One hundred extracted mandibular premolars were prepared and root‐filled with gutta‐percha and sealer. Root fillings were removed with K‐files according to the following techniques: Group A – hand instrumentation; Group B – Endo‐Gripper system driven by compressed air; Group C – INTRAmatic 29CH + INTRA‐LUX 3LD driven by compressed air; Group D – Endo‐Gripper system driven by electric engine; Group E – INTRAmatic 29CH + INTRA‐LUX 3LD driven by electric engine. The amount of filling debris on root canal walls was assessed radiographically and analysed using Auto CAD 2000 software. One‐way anova and Duncan’s test revealed statistically significant differences only in the middle third (P = 0.01); the best results being reached in group D. The apical third displayed the greatest amount of filling material debris, regardless of the technique used.     

Expression of Notch signalling-related genes in normal and differentiating rat dental pulp cells

Notch signalling is of fundamental importance to various processes during embryonic development and in adults. The possible role of Hey1, an important Notch signalling component, in odontoblast differentiation was evaluated in this study. Primary cultured dental pulp cells, derived from upper incisors of 5-week-old Wistar rats, were placed in α-modification of Eagle's minimal essential medium supplemented with 10% Fetal Bovine Serum (FBS), and ascorbic acid (AA) and β-glycerophosphate (β-GP), with or without dexamethasone, and cultured on dishes coated with collagen type IA for 7 days. Conventional and real-time Polymerase Chain Reaction (PCR) was performed to determine the expression of Notch-related genes and dentin sialophosphoprotein as a marker of odontoblast differentiation. Dentin sialophosphoprotein and Hey1 expression was significantly increased and decreased in the presence of AA + β-GP compared with controls, respectively. These findings suggest that Hey1 may be a negative regulator in odontoblast differentiation.     

SEM evaluation of the apical external root surface of teeth with chronic periapical lesion

The aim is to verify, under scanning electron microscopy, the occurrence of apical root resorption in anterior and posterior teeth with chronic and radiographically visible periapical lesions. Thirty‐two teeth were extracted, the apical thirds (n = 39) were removed, and prepared to analyse the external apical root surface. All specimens presented irregular areas of root resorption with different depths, located mainly around the apical foramen. Teeth with chronic periapical lesions present areas of external apical root resorption with irregular surface and different depths located mainly around the apical foramen. Root resorptions may show different configurations and destroy the apical root structure more or less extensively.     

MTA pulpotomy of human permanent molars with irreversible pulpitis

The histological success of mineral trioxide aggregate (MTA) pulpotomy for treatment of irreversible pulpitis in human teeth as an alternative treatment was investigated in this study. Fourteen molars which had to be extracted were selected from patients 16–28 years old. The selection criteria include carious pulp exposure with a history of lingering pain. After isolation, caries removal and pulp exposure, MTA was used in pulpotomy treatment. Patients were evaluated for pain after 24 h. Two patients were lost from this study. Twelve teeth were extracted after 2 months and were assessed histologically. Recall examinations confirmed that none of the patients experienced pain after pulpotomy. Histological observation revealed that all samples had dentin bridge formation completely and that the pulps were vital and free of inflammation. Although the results favour the use of MTA as a pulpotomy material, more studies with larger samples and a longer recall period are suggested to justify the use of MTA for treatment of irreversible pulpitis in human permanent teeth.     

Evaluation of cytotoxicity of two root canal filling materials by MTT assay

The aim of this study was to assess the cytotoxicity of two root filling materials GuttaFlow (GF) and gutta-percha (GP) on mouse fibroblasts cell line L-929. In this study there were four groups: GP and GF were considered as study groups and the other two were negative control groups. GP and GF were prepared according to manufacturer's instruction. L-929 fibroblast cells of mouse were passaged with trypsin (Merck, Germany) after elimination of freeze phase. Adequate trypsin was added to cells and they were prepared with 95% of cell vitality. After 24 h, 150 000 cells were put in each well. The cell and dimethyl methacrylate were used as negative and positive controls. Ten specimens from each group were brought into contact with the culture medium and were incubated under sterilised conditions 24 h later. The cytotoxicity of all samples was assessed by dimethylthiazol diphenyltetrazolium bromide test after 1 h, 24 h and 72 h. The results showed that cytotoxicity of GF was less than GP when assessed at 24 h and 72 h, but there was no significant difference at 1 h. In GF, the most and least cytotoxicity were observed at 24 h and 72 h while cytotoxicity of GP increased with time.     

Non‐surgical management of paraesthesia and pain associated with endodontic sealer extrusion into the mandibular canal

The aim of this report was to present a case of endodontic sealer extrusion into the mandibular canal in a 42‐year‐old woman. The patient was referred to the Endodontology and Stomatology Clinics, School of Dentistry, Estácio de Sá University, complaining of 5‐day duration intense spontaneous pain and paraesthesia, both arising after an endodontic intervention. Conventional radiographs and computed tomography of the mandible showed the presence of radiopacities inside the right mandibular canal. History and these radiographs confirmed extrusion of endodontic sealer. Treatment included an anti‐inflammatory drug, completion of endodontic treatment and follow up. The patient reported gradual improvement, becoming asymptomatic after 2 months. Radiographs 30 months after initial examination revealed partial resorption of the foreign material. In conclusion, iatrogenic extrusion of endodontic materials should be included in differential diagnosis of endodontic pain and can sometimes be managed through non‐surgical interventions in some cases.     

Risk factors for obstructive sleep apnea syndrome screening in mood disorder patients

Aims:  Previous studies have reported that the incidence of obstructive sleep apnea syndrome (OSAS) in patients with depression is higher than in the general population. We examined the risk factors to predict OSAS in mood disorder patients with depressive symptoms.
Method:  We conducted polysomnography for patients who satisfied the following criteria: (i) diagnosis of major depressive disorder or bipolar disorder according to the Mini-International Neuropsychiatric Interview (MINI); (ii) a score of ≥10 on the Hamilton Rating Scale for Depression (HAM-D); (iii) fulfillment of either (a) or (b) below: (a) at least one of the following: severe snoring, witnessed apnea during sleep, excessive daytime sleepiness; (b) at least one of the following plus an oxygen desaturation index of 4% ≥5 times/h by pulse oximeter: mild snoring, sleep disturbance, headache, high blood pressure. The patients with apnea hypopnea index ≥5 were diagnosed with OSAS.
Results:  Of the 32 mood disorder patients who met the subject conditions, 59.4% had OSAS. The diagnosis rate with our criteria was significantly higher than the previously reported incidence of OSAS in patients with depression. There was no significant difference among diagnosis rates as to individual risk factors or the number of risk factors. A multiple regression test showed no significant association between apnea–hypopnea index and other clinical factors including depression severity.
Conclusion:  The present results showed that OSAS can be detected at a remarkably higher rate by considering appropriate OSAS risk factors in mood disorder patients, and suggested that there is a high rate of undetected and therefore untreated OSAS among mood disorder patients.     

Effect of 17% EDTA and MTAD on intracanal smear layer removal: A scanning electron microscopic study

The purpose of this study was to determine the effectiveness of MTAD as the final irrigant to remove the smear layer, compared with that of 17% EDTA, both following root canal irrigation with 5.25% sodium hypochlorite (NaOCl). Fifty‐five extracted maxillary and mandibular single‐rooted human teeth were prepared by a crown‐down technique using rotary 0.04 and 0.06 taper nickel‐titanium files. 5.25% sodium hypochlorite was used as the intracanal irrigant. The canals were then treated with 5 mL of one of the following solutions as final rinse: 5.25% sodium hypochlorite, 17% EDTA or MTAD. The presence or absence of smear layer in the coronal, middle and apical portion of each canal was examined with a scanning electron microscope. The results showed that MTAD is an effective final rinse solution for removing the smear layer in canals irrigated with sodium hypochlorite. When 17% EDTA was used as a final rinse, the smear layer was removed from the middle and coronal thirds of canal preparations, but it was less effective in the apical third of the canals.