Department of Restorative Dental Sciences, College of Dentistry, Jazan University, Jazan, Saudi Arabia.
Department of Restorative Dental Sciences, College of Dentistry, Jazan University, Jazan, Saudi Arabia.
J Endod. 2019 Oct;45(10):1209-1218. doi: 10.1016/j.joen.2019.06.009. Epub 2019 Aug 1.
The aims of this in vivo cone-beam computed tomographic (CBCT) study were to evaluate the prevalence, characteristics, and correlations between the fused rooted maxillary first and second molars as well as their consequent merged and C-shaped canals in a Saudi Arabian population.
CBCT imaging of 726 maxillary first and second molars from 208 subjects of Saudi origin were evaluated in the present study. The prevalence of fused rooted maxillary molars, merged canals, C-shaped configurations, and correlations between the presence of fused rooted teeth between first and second molars were examined as the primary outcome. Differences by sex, location in the jaw, and bilateral symmetry (similarity between right- and left-side teeth in the same patient) were evaluated as the secondary outcome. The Z test was used for differences in the independent proportions, the chi-square test was used for differences between sex and locations, and the Cohen kappa test was used for bilateral symmetry. The kappa test was also used for intrarater reliability. A value of P < .05 was considered significant.
The prevalence of fused rooted maxillary first and second molars was 7% and 21%, respectively. Within fused rooted teeth, the presence of merged canals was 8.3% and 32.1%, whereas the prevalence of C-shaped canals was 8.3% and 5.1% in first and second maxillary molars, respectively. Among 57 subjects who had fused rooted maxillary molars, 19.3% showed a correlation between first and second molars. In fused rooted maxillary molars, 3.8% first molars and 13% second molars were bilaterally symmetrical. There were no statistically significant differences between sexes and right- and left-sided fused rooted maxillary molars, merged canals, or C-shaped canals.
Maxillary second molars presented more complex external and internal morphology compared with maxillary first molars, with an overall prevalence of 14% of fused rooted maxillary molars and 3.7% merged and 0.8% C-shaped canal configurations for all maxillary molars. The clinician should be aware of such challenges, and for a better treatment outcome, the use of CBCT imaging (small field of view) and an operative dental microscope can be considered when a preoperative periapical radiograph shows signs of fused rooted maxillary molars.
本体内锥形束计算机断层扫描（CBCT）研究的目的是评估沙特阿拉伯人群中融合根上颌第一和第二磨牙的流行率、特征以及它们融合的、合并的和 C 形根管之间的相关性。
本研究评估了 208 名沙特阿拉伯人共 726 颗上颌第一和第二磨牙的 CBCT 图像。主要观察指标为融合根上颌磨牙、合并根管、C 形形态的发生率，以及第一和第二磨牙之间融合根牙的存在的相关性。其次观察指标为性别、颌骨位置和双侧对称性（同一患者右侧和左侧牙齿的相似性）的差异。独立比例的 Z 检验、性别和位置的卡方检验以及双侧对称性的 Cohen kappa 检验用于分析。kappa 检验也用于评估内部一致性。P 值<.05 被认为具有统计学意义。
融合根上颌第一和第二磨牙的发生率分别为 7%和 21%。在融合根牙中，合并根管的发生率分别为 8.3%和 32.1%，而第一和第二上颌磨牙的 C 形根管发生率分别为 8.3%和 5.1%。在 57 名有融合根上颌磨牙的患者中，19.3%的患者第一磨牙和第二磨牙之间存在相关性。在融合根上颌磨牙中，3.8%的第一磨牙和 13%的第二磨牙双侧对称。性别、右侧和左侧融合根上颌磨牙、合并根管或 C 形根管之间无统计学差异。
上颌第二磨牙的外部和内部形态比上颌第一磨牙更复杂，总体而言，融合根上颌磨牙的发生率为 14%，所有上颌磨牙的合并根管和 0.8% C 形根管发生率分别为 3.7%和 0.8%。临床医生应注意到这些挑战，对于更好的治疗效果，当术前根尖片显示融合根上颌磨牙的迹象时，可以考虑使用 CBCT 成像（小视野）和手术牙科显微镜。
