Four-Rooted Maxillary First Molars: A Systematic Review and Meta-Analysis.

OBJECTIVES: The majority of human maxillary first molars is usually described as having three roots, but different morphologies were documented in several studies and case reports. One very rare and less investigated anatomical anomaly is the occurrence of four radicular structures in the upper first molars. This communication aimed to define the prevalence of four-rooted maxillary first molars on a meta-analytical basis. The external and internal morphology of these teeth was described by the collection of published case reports. MATERIALS AND METHODS: Six electronic databases were accessed to collect case reports dealing with four-rooted maxillary first molars, as well as population-based cone-beam computed tomography (CBCT) studies. Afterward, the publications were selected according to predefined inclusion/exclusion criteria and evaluated using the Joanna Briggs Institute Critical Appraisal tool. The teeth of the chosen case reports were then independently analyzed by two dental professionals according to different dental classifications. Furthermore, the population studies were meta-analyzed to calculate the global and regional prevalence of four-rooted maxillary molars. RESULTS: Included were forty-nine population-based CBCT studies containing 26663 maxillary first molars. Upon these data, the global incidence of four-rooted maxillary molars was meta-analytically determined as 0.047% (95%-CI:0.011-0.103%). In combination with the case reports, it was pointed out that this anomaly is distributed worldwide. Furthermore, forty-eight case reports were included containing fifty-three maxillary molars with four roots. The analyzed teeth exhibited Versiani´s pulpal chamber floor Types A and B. The majority of four-rooted maxillary first molars were classified as Type I regarding Christie's configuration. But, also 7.54% of the altered teeth could not be described by this classification. 62.34% exhibited four root canals, but also variations with five, six, or seven canals were identified. Furthermore, a significant difference was found in the occurrence rate between male and female patients. CONCLUSION: Due to the worldwide occurrence, dental professionals should be aware of this rare anomaly to avoid treatment errors, especially during endodontic or surgical therapies.

Endodontic Retreatment of Maxillary Second Molar with Four Roots.

The present communication describes the endodontic retreatment of a rare four-rooted maxillary second molar. A 25-year-old patient was referred to our dental practice requesting an apicoectomy because of continuous and permanent pain reaction six months after the first endodontic treatment. The sent radiograph demonstrated three filled root canals (one mesial, two distal) and four radiographically superimposing roots (two mesial, two distal). Due to the diagnosed chronic apical periodontitis and based on the visible untreated root canal, we decided to endodontically re-treat the quadrangular tooth against the referred apicoectomy. In the first session, only the previously untreated mesiopalatal root canal was mechanically prepared and filled with a corticosteroid- and tetracycline-containing paste. After two symptom-free weeks, the gutta-percha was removed from the other canals and calcium hydroxide was applied. Another two weeks later, the four root canals, whose orifices were "irregular quadrilateral" shaped on the pulp chamber floor representing Versiani Type A, were obturated. After the verification of this rare anatomy by cone beam computed tomography, the tooth was classified as Christie's radicular type II. One characteristic of this type is parallel running buccal and palatal roots, which caused a radiographic superimposition and probably led to the endodontic mistreatment in the first case.

Non-pharmacological interventions for reducing mental distress in patients undergoing dental procedures: Systematic review and meta-analysis.

OBJECTIVES: This meta-analysis investigates the efficacy of non-pharmacological interventions in adults undergoing dental procedures under regional or general anesthesia compared to standard care alone or an attention control group on the reduction of mental distress, pain, and analgesic use. DATA SOURCES: To identify relevant papers a comprehensive literature search was carried out in MEDLINE, CENTRAL, Web of Science, and PsycINFO (last search August 2017). Additionally, lists of references of relevant articles and previous reviews were checked. ProQuest Dissertations and Theses Full Text Database was screened to identify any unpublished material. STUDY SELECTION: A total of 29 eligible randomized controlled trials were included, comprising a total of 2.886 patients. Included trials investigated the effects of hypnosis, enhanced information, relaxation, music, or cognitive-behavioral approaches including distraction. RESULTS: Random effects meta-analyses revealed significant positive treatment effects on the reduction of mental distress (g = 0.58, CI 95% [0.39; 0.76]). Effects on pain relief (g = 0.00, CI 95% [-0.28; 0.28]) and the reduction of analgesic use (g = 0.26, CI 95% [-0.22; 0.73]) were not significant. Because effects on mental distress were substantially heterogeneous, subgroup analyses were run yielding significantly larger effects for studies with low risk of bias compared to studies with high or unclear risk of selection and attrition bias. No significant differences appeared between various types of non-pharmacological interventions. CONCLUSIONS: In summary, benefits of non-pharmacological interventions on reducing mental distress were demonstrated with largest effects being shown for hypnosis. However, further high quality trials are needed to strengthen the promising evidence. CLINICAL SIGNIFICANCE: This systematic review and meta-analysis indicated that non-pharmacological interventions may be beneficial for reducing mental distress in patients undergoing dental procedures and could thus be considered as valuable adjunct to standard care.

Expression of the IGF-1, IGFBP-3 and IGF-1 receptors in dental pulp stem cells and impacted third molars.

IGF-1 regulates the metabolism of hard dental tissue through binding to the IGF-1 receptor on target cells. Furthermore, IGF-binding-protein-3 promotes the accessibility of IGF-1. The aim of this study was to investigate the expression of IGF-1, IGFBP-3 and IGF-1R in STRO-1-positive dental pulp stem cells (DPSCs) and fully impacted wisdom teeth in relation to tooth development. Third molars were surgically removed from 60 patients and classified into two groups: teeth showing ongoing development (group 1) and teeth that had completed root shaping (group 2). The transcript and protein levels of IGF-1, IGFBP-3 and IGF-1R were investigated using RT-PCR and immunohistochemistry. The expression of the same proteins was also analyzed in DPSCs. The teeth from group 1 showed significantly stronger expression of IGF-1 and IGF-1R. The major sources of all of the proteins investigated immunohistochemically in sections of wisdom teeth were odontoblasts, cementoblasts and cell colonies in the pulpal mesenchyme. These colonies were identified as stem cells in view of their positivity for STRO-1, and the cells were subsequently sorted by flow cytometry. These DPSCs demonstrated high levels of pluripotency markers and IGF-1 and IGF-1R. We conclude that members of the IGF-1 family are involved in the late stage of tooth development and the process of pulpal differentiation.