Association between odontogenic conditions and maxillary sinus abnormalities: a retrospective cone-beam computed-tomographic study.

BACKGROUND: In this study, we investigated the correlation between odontogenic conditions and the presence of maxillary sinus (MS) abnormalities using cone-beam computed tomography (CBCT) imaging. METHODS: The study unit was defined as the ipsilateral MS, maxillary alveolar bone, and posterior teeth. The study included 1,140 study units from 570 patients visualized with CBCT. MS abnormalities, MS septal walls, the anatomical relationship between the MS and the teeth, and missing teeth were recorded. Adjacent odontogenic infections, including periapical lesions, periodontal bone loss, and combined periodontal-endodontic lesions, were documented, and the shortest distance between the infection and the MS floor was measured. The possible correlations between odontogenic conditions and MS abnormalities were analyzed. Whether the anatomical relationship between the MS and the teeth was related to age or sex was analyzed. The chi-squared test, Fisher's exact test, Mann-Whitney U test, Kruskal-Wallis H test, and logistic regression were used for the statistical analyses. RESULTS: MS abnormalities were detected in 57.54% of patients and 42.89% of MSs. Male sex (OR =1.653; P<0.001) and a MS adjacent to teeth with periapical lesions (OR =5.771; P<0.001), periodontal bone loss (OR =2.778; P<0.001), or combined periodontal-endodontic lesions (OR =13.818; P<0.001) increased the probability of MS abnormalities. In MSs with a single infected tooth, male sex (OR =2.413; P=0.045), infected molar (OR =3.431; P=0.008), and a smaller distance between the infection and the MS floor (OR =0.871; P=0.021) increased the probability of MS abnormality. The maxillary root apices of older subjects tended to be farther from the MS (P<0.001). CONCLUSIONS: Adjacent odontogenic infection increased the probability of MS abnormalities. The likelihood of MS abnormality was related to the distance between the infection and the MS, not to the type of infection.

Evaluation of a broken instrument removal training course for general dentistry residents.

INTRODUCTION: To help general dentistry residents better manage the intracanal broken instrument situation, we introduced a hands-on training course into the endodontic curriculum of a general dentistry residency programme. MATERIALS AND METHODS: Thirty general dentistry residents and 30 residents with endodontic specialty training background in a general hospital served as the experimental group and reference group, respectively. The experimental group underwent a training course including a 30-min lecture and two hands-on sessions (2 h each). After the course, residents from both groups were asked to perform the instrument removal procedure on simulated root canals. Success rate, procedure time and canal volume change were compared between groups. Questionnaire results were also analysed. RESULTS: All residents successfully managed to remove the broken instruments in the test. Procedure time was significantly longer for general dentistry residents (15.8 ± 5.7 min vs 13.7 ± 4.5 min, Mann-Whitney U test, p = .038). Canal volume change was significantly greater for general dentistry residents (8.53 ± 3.82 µl vs 5.94 ± 2.73 µl, independent-samples t-test, p = .004). In the questionnaires, trainees gave overall positive ratings for the course. The marginal homogeneity test on before and after scores of the questionnaire items showed the training helped the trainees to reduce the stress level associated with instrument breakage (p < .001). It also motivated the trainees to remove the broken instrument in some straightforward cases (p < .001). CONCLUSION: The broken instrument removal training course could help the general dentistry residents better manage the intracanal broken instrument situation.

Non-syndromic familial congenital dental deficiency: two cases report.

Congenital dental deficiency can lead to aesthetic and masticatory dysfunction, which have a great effect on the quality of life of patients. Genetic inheritance is the determining factor of congenital dental deficiency, which may follow the pattern of autosomal dominant, recessive, or sex chromosome inheritance. However, the specific genetic mechanisms are not clear. The prevalence of congenital absence of permanent teeth in the general population worldwide are not high, and familial oligodontia in clinically healthy patients is rare. This paper reported two cases of familial non-syndromic congenital teeth loss and included a review of literature referring to the etiology, clinical manifestations, and treatment of congenital dental deficiency.

[Root canal treatment of two-rooted three-canal maxillary first premolar: a case report].

According to literature, the incidence of three-canal maxillary first premolar is between 0.5% and 7.5%. The two types of three-canal maxillary premolars are two-rooted and three-rooted three-canal maxillary premolars. Most case reports in Chinese literature focus on three-rooted three-canal maxillary premolars. To our knowledge, no domestic case report on two-rooted three-canal maxillary premolar has been published. In this study, we describe the root canal treatment of a two-rooted three-canal maxillary premolar.

[The clinical study on the use of diode laser irradiation in the treatment of periodontal-endodontic combined lesions].

OBJECTIVE: To evaluate the adjunctive effect of diode laser irradiation for the treatment of periodontal-endodontic combined lesions. METHODS: 30 cases with periodontal-endodontic combined lesions were selected. All cases were randomly divided into experimental group and control group (n=15). In the control group, patients were treated with root canal therapy and conservative periodontal treatment (scaling and root planning), and patients in the experimental group were treated with root canal therapy and conservative periodontal treatment followed by diode laser irradiation. Clinical measurements including pocket probing depth (PPD), clinical attachment level (CAL), modified bleeding index (mBI), periapical index (PAI) were taken before treatment (baseline). Three and six months after the treatment, the adjunctive effects of diode laser in the treatment of periodontal-endodontic combined lesions were evaluated. RESULTS: Three months after the treatment, the average PPD, CAL and mBI levels were reduced significantly in both groups. But the average PPD reduction in the experimental group was significantly greater (P<0.05) than in control group. However the average CAL and mBI reduction were not significantly different between two groups. Six months after the treatment, the average PPD, CAL and mBI levels were further reduced in the experiment group, but not in the control group. The average PAI levels were reduced significantly in both groups, but the PAI reduction was not significantly different between two groups. CONCLUSION: The use of diode laser as an adjunct procedure in the treatment of periodontal-endodontic combined lesions can aid in achieving success.

[Fracture of the separated nickel titanium instruments during ultrasonic removal: an experimental study].

OBJECTIVE: This in vitro study is to evaluate the effect of ultrasonic power settings and cooling methods on fracture behavior of the separated nickel titanium instruments during ultrasonic removal. METHODS: 40 discarded and 10 new nickel titanium instruments were used to establish the separated instrument removal model. The discarded instruments were divided into four groups according to two ultrasonic power settings(6 or 10) and different cooling methods (using water coolant or without using water coolant), and all the new instruments were put into the group in which ultrasonic vibration was used at a higher power setting (10) without using water coolant. The time required for fracture of the separated instruments was recorded. RESULTS: The time was longer with statistical significance at a lower power setting compared with that at a higher power setting regardless of the use of water coolant. The time was longer with statistical significance by the use of water coolant compared with that without using coolant regardless of power settings (6 or 10). The time required for fracture of the new instruments was longer than that of the discarded instruments with statistical significance. CONCLUSION: During ultrasonic removal of separated nickel titanium instruments, water coolant could decrease the occurrence of fracture. When removing separated nickel titanium instruments with ultrasonic vibration, an attempt without coolant shouldn't be made at a higher power setting.

[Clinical evaluation of large periapical lesions following apical surgery].

OBJECTIVE: To evaluate the therapeutic effect of teeth with large periapical lesions followed apical surgery. METHODS: 59 patients (59 periapical lesions, 91 teeth) with large periapical lesions ranging in size from 6 mm to 21 mm in diameter were included in this study. All teeth were treated by root canal therapy and apical surgery, and the surgical procedure was completed with microsurgical technology and ultrasonic root-end preparation. The outcomes were evaluated clinically and radiographically at 1, 3, 6, 9, 12 and 24-month intervals, and the various factors which may affect the success rate were analyzed statistically. RESULTS: 52 cases (88.1%) of 59 patients were considered success, 6 cases (10.2%) were considered failure, and 1 case (1.7%) was considered in progress. The success rate of elderly patients group (63.6%) was significantly lower than that of the youth group (87.5%) and middle-aged group (95.0%) (P = 0.037; P = 0.017). The success rate of molar group (75.0%) was significantly lower than that of the anterior group (92.6%) and the premolar group (90.0%) (P = 0.041, P = 0.047); however, there was no significant difference in the gender, the number of teeth invaded in lesions, the size of periapical lesion (P > 0.05). CONCLUSION: It is an effective therapy for the teeth with large periapical lesions by apical surgery after root canal treatment.

[Clinical evaluation on the root canal therapy bypassing intracanal separated instruments].

OBJECTIVE: To study and evaluate the clinical effect of root canal therapy bypassing intracanal separated instruments. METHODS: 32 teeth were selected as the test group, from which the intracanal separated instruments couldn't be taken out, adopted the method of root canal preparation and obturation bypassing broken instruments. Meanwhile, 13 teeth were selected as the control group, in which the fractured instruments couldn't be taken out from root canal, and not be cured bypassing broken instruments. 30 teeth were selected as the conventional therapy group, in which the instruments were not fractured, the routine root canal therapy were adopted. The clinical efficacy of three groups were observed and evaluated through periapical index and clinical examination two years later. RESULTS: After two years, 25 teeth were followed up in test group, the success rate of root canal therapy was 80.00%; 11 teeth were followed up in control group, the success rate of root canal therapy was 36.36%. All of the failed cases in two groups were the teeth with broken instruments in tip of root canal. In conventional therapy group, 22 teeth were followed up, and the success rate of root canal therapy was 90.91%. CONCLUSION: Root canal therapy bypassing intracanal separated instruments is a feasible and effective method in treating the teeth with broken instruments.