Endodontic management of the maxillary first molars with two root canals: A case report and review of the literature.

BACKGROUND: The complex anatomy of the maxillary first molars has always been a major challenge for complete root canal treatment in endodontic therapy. Here, we present two cases of maxillary first molars, each with only two root canals, which have been rarely reported. We also perform a literature review of maxillary first molar anatomy. CASE SUMMARY: The two patients were referred to the hospital after 1) finding a cavity in their tooth with a color change and, 2) a toothache during mastication, respectively. Both of these cases were diagnosed as apical periodontitis by X-ray imaging and cone beam computed tomography (CBCT). Non-surgical endodontic therapy was performed with the assistance of a dental operating microscope (DOM). CBCT showed rare but accurate images of both patients, each with two root canals and two roots in their maxillary first molars. Both roots were located in the buccal in the palatal direction, and each root had only one clear root canal. In addition, each maxillary first molar in both patients was symmetrical to that on the opposing side with only two separate root canals. Non-surgical endodontic therapy was performed with the assistance of a DOM. Finally, the teeth were restored using composite resin and the patients were satisfied with the results. CONCLUSION: Making full use of CBCT and DOM would contribute to helping dentists make correct diagnoses and successfully treat teeth with rare root canal morphologies.

[Expression of transient receptor potential vanilloid 3 ion channel protein in human odontoblasts].

OBJECTIVE: To investigate the expression of transient receptor potential vanilloid 3 (TRPV3) ion channel protein in human odontoblasts (OD). METHODS: Twenty intact and healthy third molars extracted for orthodontic purpose were included. The quality of dental tissue sections was determined through HE staining, and the OD layer was further determined by dentin sialophosphoproteins (DSPP) antibody staining, and finally the expression of TRPV3 ion channel protein in human dental pulp tissue was examined by TRPV3 ion channel protein-specific antibody. The expression of TRPV3 channel proteins in human OD at different part of dental pulp was compared using Image Pro Plus (IPP) and SPSS software. RESULTS: TRPV3 channel protein expressed on the cell body of OD in the coronal and root pulp, and the expression in the coronal pulp was significantly higher than that in the root pulp. The TRPV3 protein also expressed at the odontoblastic process, with the higher expression in the crown (IA = 2516 ± 162) than in the root (IA = 2224 ± 150) and external root (IA = 2121 ± 92) (P < 0.05), but the expression between the lateral root area and external root area was not significantly different (P > 0.05). CONCLUSIONS: Human odonoblasts expressed TRPV3 ion channel protein and the expression level was different at different part of dental pulp OD.

[Re-mineralization ability of Galla chinensis extracts on root carious lesions with or without non-collagen proteins].

OBJECTIVE: To evaluate the re-mineralization ability of Galla Chinensis extracts (GCE) on two artificial carious lesions in bovine root de-mineralized in vitro. METHODS: Fourteen bovine root blocks were divided into two parts from buccal to lingual direction. The mesial blocks were treated with a demineralization solution and the distant blocks were treated with another demineralization solution. Two specimens from each group were selected randomly and examined with polarization microscope (PLM). After all blocks were demineralized, half surface of the demineralized zone was covered and the another half was treated with 0.5% NaCl to extract soluble dentin phosphate protein (S-DPP). Then all specimens were submitted to pH-cycling for one week. In the first four days, all specimens were treated with GCE for 21 h and with demineralization solution for 3 h. In the remaining three days, all specimens were treated with GCE. The re-mineralization ability of GCE on the specimens was evaluated by laser scanning confocal microscope (LSCM). RESULTS: There existed intact surface layers on subsurface lesions but no surface layers were produced on erosive lesions. The re-mineralization ability of GCE on erosive lesions improved significantly with the treatment of 0.5% NaCl solution (P < 0.05). But it had no significant effect on subsurface lessions. CONCLUSION: Extraction of S-DPP with 0.5% NaCl can improve the re-mineralization ability of GCE on root caries with erosive lesions. This finding supports the proposition that Galla Chinesis may be a promising anti-caries natural medicine in the future.

Effect of Galla chinensis on the remineralization of two bovine root lesions morphous in vitro.

The present study aims to evaluate the effect of Galla chinensis compounds on the remineralization of two artificial root lesions morphous in vitro. Sixty bovine dentine blocks were divided into two groups and individually treated with two levels of demineralization solutions to form erosive and subsurface artificial carious lesions in vitro. Each group was then divided into three subgroups, each of which were treated with a remineralization solution (positive control), deionized water (negative control), or 4 000 mg⋅L(-1) aqueous solutions of Galla chinensis extract. The dentine blocks were then subjected to a pH-cycling regime for 7 days. During the first 4 days, the daily cycle included 21-h deal and 3-h demineralization applications. The dentine blocks were dealt with the entire day during the remaining 3 days. Two specimens from each of the treatment groups were selected and observed under a polarized light microscope. Data collected using a laser scanning confocal microscope were computerized and analyzed. Galla chinensis extract clearly enhanced the remineralization of both erosive lesion and subsurface lesion patterns in the specimens (P<0.05). The level of remineralization of the erosive lesion by Galla chinensis extract was lower than that of the subsurface lesion (P<0.05). In addition, the remineralization of the subsurface lesion by Galla chinensis extract was higher than that of the remineralization solution (P<0.05). No significant difference between the remineralization of erosive lesions by Galla chinensis extract and the remineralization solution was observed (P>0.05). So Galla chinensis extract has the potential to improve the remineralization of artificial root lesions under dynamic pH-cyclic conditions, indicating its potential use as a natural remineralization medicine.

[Cross-sectional study of dentine hypersensitivity in smaller cities and rural area in Sichuan province].

OBJECTIVE: To investigate the clinical characteristics and risk factors of dentine hypersensitivity in smaller cities and rural area in Sichuan province. METHODS: The examinee aged 20 - 69 years old were interviewed and divided into five age groups (20 - 29, 30 - 39, 40 - 49, 50 - 59 and 60 - 69). The random sampling methods were performed in this study. A total of eight spots were survied, including 4 communities and 4 spots in rural area of Sichuan province. The information about the examinee's age, gender, occupation, education level, tooth brushing methods, the frequencies of eating fresh fruits and fruit juices and so on, were asked and recorded. All subjects were further diagnosed by a blast of air from a triple syringe connected to an air compressor at a pressure of 4 atm under room temperature of about 19 - 24°C. RESULTS: The premolars were the most commonly affected, followed by the first molar. The exposed root surface was the most commonly affected position [63.87% (663/1038)]. The first premolar had the greatest number of teeth with dentine hypersensitivity [29.96% (311/1038)]. Different tooth had different sensitive position. Female, too much time of using a tooth brush, and hydrochloric acid in gastric juice were risk factors for dentine hypersensitivity (OR value = 2.175, 1.157, 1.760). CONCLUSIONS: Dentine hypersensitivity is influenced by multiple factors. Prevention and treatment need be performed by improving general oral health and periodontal conditions.

[Epidemiological survey of dentine hypersensitivity of 630 adults in rural of Sichuan province].

OBJECTIVE: To investigate the prevalence and potential risk factors of dentine hypersensitivity of adults in rural of Sichuan province. METHODS: All representative samples, including 630 adults living in rural of Sichuan Province, were selected by multi-stage, stratified and random sampling. The dentine hypersensitivity of all 630 cases was surveyed with questionnaire and oral clinical examination. SPSS 18.0 software was used for statistical analysis. RESULTS: 27.9% of all subjects were suffered from dentine hypersensitivity, sour was the most common stimulus of dentine hypersensitivity. The first premolar was the most common tooth with dentine hypersensitive, which occupied 27.4% of the total affected teeth. Female, acid regurgitation symptom, low frequency of toothbrush replacement (over 3 months), high tooth-brushing force and frequency of fresh fruits consumption (over 2 times per week) probably were high risk factors of dentine hypersensitivity. CONCLUSION: The prevalence of dentine hypersensitivity occurs in rural of Sichuan province is high, thus for future the publicity and education on dentine hypersensitivity preventive should be strengthened.

[Epidemiological survey of dentine hypersensitivity of young people in Chengdu City].

OBJECTIVE: To investigate the prevalence and risk factors of dentine hypersensitivity of young people in Chengdu city. METHODS: The dentine hypersensitivity of 741 cases aged 18-35 living in Chengdu city were surveyed with questionnaire and oral examination by random collection during June to July in 2008. The relative risk factors to dentine hypersensitivity were analyzed. RESULTS: 128 cases (17.27%) were diagnosed as dentine hypersensitivity. The prevalence of dentine hypersensitivity was higher among female than male (P<0.01). Cold was the most common stimulus for dentine hypersensitivity (62.80%). The most common affected tooth was the right maxillary first premolar (15.51%). Acid regurgitation, carbonated beverage, hard toothbrush type and heavy toothbrushing force were risk factors to dentine hypersensitivity. CONCLUSION: The prevalence of dentine hypersensitivity of Chengdu city's young people is widespread. Acid and incorrect toothbrushing methods can cause dentine hypersensitivity. The correct protective measure to dentine hypersensitivity should be publicized.

[The influence of age upon circadian rhythm of human pulp sensibility].

OBJECTIVE: To explore the influence of age on the circadian rhythm of pulp sensibility, guide the diagnosis and treatment of dental and endodontic diseases. METHODS: The first lower molars of young, middle-aged, and aged volunteers were inspected for the threshold of pulp sensitivity. Each inspection was implemented every 4 hours earlier, totally 7 times during 24 hours. All values of pulp sensibility threshold from each volunteer were analyzed by Halberg methods for cosinor-rhythmometry. The chronobiology characteristics of pulp sensibility were compared among young, middle-aged, and aged. RESULTS: The pulp sensibility threshold values of the young, middle-aged, and aged indicated to have the circadian rhythm alternation in period of 24 hours, with fitting well to a cosine curve. The trend of rhythm curve was similar to all three age groups. The acrophase and bathyphase appeared at 0:00 and 12:00 separately. The values and amplitudes of pulp threshold sensibility showed to be: young>aged> middle-aged. CONCLUSION: The circadian rhythm of pulp sensibility changes according with age. The pulp sensibility threshold value is lower in aged people than in the young, and the lowest sensibility threshold is in middle-aged people. Besides, the extent of rhythm fluctuation is the least in middle-aged people.

[Comparison of the painless effect of four anesthetic methods during pulpal treatment].

OBJECTIVE: To compare the painless effect of four anesthetic methods during opening pulp cavity and undergoing pulpectomy for acute or chronic pulpitis. METHODS: 80 teeth of 80 patients were randomly allocated into four groups. Each group had 20 teeth. Anesthetic methods applied four different groups included block anesthesia of nerve, supraperiosteal infiltration, periodontal membrane injection and intrapulpal injection. Anesthesia doses were recorded and the pierced points, the zones of pain, the time of anesthesia action, the time of anesthesia persistence and the degrees of anesthesia were evaluated with four levels synthetic evaluation standard of anesthesia. RESULTS: Compared with periodontal membrane injection and intrapulpal injection, block anesthesia of nerve and supraperiosteal infiltration had the later time of anesthesia action and the longer time of anesthesia persistence (P<0.05). In four anesthetic methods, block anesthesia of nerve had the best painless effect (P<0.05). CONCLUSION: Four anesthetic methods have their own superiorities, and we should select proper anesthetic methods in clinical work.

[Effect of light-emitting diode curing light and halogen light on microleakage of extracted teeth].

OBJECTIVE: To evaluate the effect of light-emitting diode (LED) curing light and Halogen dental curing light on the microleakage of Clearfil AP-X composite restorations and to provide evidence for clinical use of LED curing light. METHODS: Class V cavities were prepared in 73 freshly extracted teeth. The teeth were randomly divided into two groups being exposed to light-emitting diode curing light MORITA PENCURE and halogen light 3M ESPE Elipar 2500 respectively, and then treated with thermocycling (500 cycles, 5-55 degrees C), section and dyeing. The amounts of dye infiltration and marginal seal were examined by stereomicroscope and scanning electron microscope (SEM) respectively. RESULTS: No significant differences were found in the amount of dye infiltration shown in the stereo-photomicrograph between the two groups. However, the SEM revealed better marginal seals of those teeth exposed to LED curing light. CONCLUSION: The LED curing light may be able to achieve the same or better effect on reducing microleakage compared with the Halogen dental curing light. Further studies are needed.