Objective: To investigate the morphological characteristics of the mandibular first premolars in people from Pearl River Delta region in Guangdong province using three techniques, including periapical radiographs, the radiographs with files inserted the canals and the clearing technique.
Methods: A total of 363 extracted mandibular first premolars were collected and numbered. Two preoperative radiographs were taken in buccolingual and mesiodistal directions respectively. After access opening, the files were placed in the canals and two other radiographs were taken. The mandibular first premolars with multi-canal system were selected and observed under dental operating microscope (DOM). The mandibular first premolars were made transparent and were categorized using the Vertucci's classification.
Results: There were different results among the three approaches. Periapical radiographs could be used to distinguish only between one and multiple canals systems. The incidence of multiple canals was 33.33% from the radiographs with file. The mandibular first premolars had a high frequency (34.44%) of multi-canal system by clearing method. The root canal morphology of the mandibular first premolars showed great variance. The canal orifices of the mandibular first premolars with one or two canal distributed in a buccolingual line. The floor of pulp chamber of the mandibular first premolars with three or four canals was a plat form.
Conclusion: The mandibular first premolars have a high frequency multi-canal system and could be classified in many categories. Using DOM and radiographs with file is a useful way in judging the canal numbers and categories.
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Dent Mater
January 2025
Minnesota Dental Research Center for Biomaterials and Biomechanics, School of Dentistry, University of Minnesota, Minneapolis, MN, USA. Electronic address:
Objective: This study compared the fracture load, stress distribution, and survival probability under cyclic loading of extensively restored teeth treated with multisonic irrigation with those treated with conventional instrumentation, with or without a post.
Methods: Mesial-occlusal-distal cavities were prepared in 30 human mandibular premolars. The teeth were randomly divided into 3 groups of 10 based on the endodontic and restorative procedures: (1) Root canal treatment (RCT) followed by resin composite restoration (control group), (2) RCT followed by a glass fiber post restoration (conventional group), and (3) minimal instrumentation plus multisonic irrigation followed by resin composite restoration (GW group).
Eur J Dent
December 2024
Department of Dental Biomaterials, Faculty of Dentistry, Mansoura University, Mansoura City, Egypt.
Objectives: Orthodontic bracket bond failure is an obstacle in clinical orthodontics. This study investigated the influence of pH cycling on the shear bond strength (SBS), adhesive remnant index (ARI), and survival probability of adhesive-precoated flash-free ceramic brackets.
Materials And Methods: Forty mandibular premolars were randomly divided into two groups ( = 20): C: noncoated orthodontic brackets, and F: flash-free adhesive-precoated orthodontic brackets.
J Indian Prosthodont Soc
January 2025
Department of Prosthodontics, K M Shah Dental College and Hospital, Sumandeep Vidyapeeth, Vadodara, Gujarat, India.
Aim: The aim is to evaluate and compare stress distribution characteristics of ball, magnet, and positioned attachment systems in single and double implant-retained overdentures using the finite element method (FEM).
Setting And Design: In vitro (in silico study) finite element analysis (FEA).
Materials And Methods: A Styrofoam mandible with duplicated silicon mucosa was used to construct a mandibular complete denture.
BMC Oral Health
January 2025
Department of Endodontics, Beijing Stomatological Hospital, Capital Medical University, Tian Tan Xi Li No.4, Beijing, 100050, China.
Background: To evaluate the prevalence and characteristics of taurodontism in northern China by using cone-beam computed tomography (CBCT) and assisting the treatment.
Methods: The study involved CBCT scans of 8112 teeth from 507 participants of northern China, comprising 217 males and 290 females aged 18 to 60. Analysis was conducted using Shifman and Chanannel's criteria to assess the prevalence and attributes of taurodontism, examining differences based on tooth position (maxilla and mandible) as well as gender (P < 0.
BMC Oral Health
January 2025
Oral and Dental Disease Research Center, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
Background: Molariform second premolar is a rare dental anomaly where the second premolar resembles a molar in size and shape. This condition is often linked to macrodontia, a rare enlargement of teeth that disrupts dental proportions and can manifest in isolated, relative, or generalized forms. Although mandibular second premolars are more prone to morphological variability, the occurrence of bilateral molariform premolars, induced by a unique form of gemination, is exceptionally uncommon and infrequently documented, thus making this case clinically significant.
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