The aim of this study was to investigate the physiological foramen diameter, shape and distance between physiological and anatomical apex of maxillary and mandibular first and second molars. Accurate knowledge of the ...The aim of this study was to investigate the physiological foramen diameter, shape and distance between physiological and anatomical apex of maxillary and mandibular first and second molars. Accurate knowledge of the physiological foramina morphology; thus, inherent mechanical shaping technical hindrances, is decisive when taking the corresponding root canal final preparation decision. The morphological dimensions of a total of 1 727 physiological foramina were investigated by means of micro-computed tomography. Mean narrow and wide （to a high number, oval） diameters of the physiological foramen were 0.24, 0.22 and 0.33 mm and 0.33, 0.31 and 0.42 mm in mesiobuccal （MB）, distobuccal （DB） and palatal （P） roots in maxillary first molars; 0.24, 0.22 and 0.33 mm and 0.41, 0.33 and 0.44 in MB, DB, and P roots in maxillary second molars. Mandibular first molars showed mean narrow and wide diameters of 0.24 and 0.30 mm and of 0.39 and 0.46 mm in mesial （M） and distal （D） roots; second mandibular molars showed 0.25 and 0.31 mm and 0.47 mm in M and D roots. The mean distance between the physiological foramina and anatomical apex was 0.82, 0.81 and 1.02 mm and 0.54, 0.43 and 0.63 mm in MB, DB and P roots of the maxillary first and second molars, respectively. A mean distance of 0.95 mm （M） and 1.05 mm （D） in the first and 0.78 mm （M） and 0.81 mm （D） in the second mandibular molars was observed. Based on the results obtained, assumable recommendations for final preparation size of the physiological foramen were calculated. However, when taking into consideration, the resulting standard deviations of marginal errors must be cautiously considered when taking a final decision in clinical endodontic treatment.展开更多
Objective: To investigate if caries in the pre-treatment early mixed dentition is associated with caries development in the permanent dentition during orthodontic treatment. Material and Methods: We included 41 consec...Objective: To investigate if caries in the pre-treatment early mixed dentition is associated with caries development in the permanent dentition during orthodontic treatment. Material and Methods: We included 41 consecutive patients (29 girls, 12 boys) with a pre-treatment documentation in the mixed (mean age 9.4 years) and a post treatment documentation in the permanent dentition (age 14.9 years) (two-phased treatment time 4.5 (±1.6) years). The DMFT/S indices were calculated. High-risk and low-risk groups were defined according to dmfs + DMFS score before treatment. Results: Initial dmft/s + DMFT/S (SD) was 5.15 (3.60) and 8.32 (6.64);final DMFT/S was 2.76 (2.84) and 3.01 (3.20). The missing (because of decay) second deciduous molars were most powerfully associated with caries increment during treatment, showing significant correlations to second premolars (r = 0.47, p = 0.003), while fillings on second deciduous molars seem to influence the prevalence of fillings on permanent molars (r = 0.44, p = 0.001). The increment at surface level was 2.01 (2.61) in the whole sample and 2.60 (3.81) in the high-risk group (4 boys, 6 girls). Compared to the low-risk group (10 girls), post-treatment caries experience was significantly higher in the high-risk group (p = 0.029). Boys were more at risk than girls (p = 0.005). Conclusions: Children with elevated caries experience in the early mixed dentition are exposed to higher caries risk during orthodontic treatment. Thus, in prevision of treatment, caries should already be assessed in the mixed dentition, so that an extended prophylaxis program can be initiated.展开更多
Calcium phosphate cements (CPC) are currently widely used bone replacement materials with excellent bioactivity, but have considerable disadvantages like slow degradation. For critical-sized defects, however, an impro...Calcium phosphate cements (CPC) are currently widely used bone replacement materials with excellent bioactivity, but have considerable disadvantages like slow degradation. For critical-sized defects, however, an improved degradation is essential to match the tissue regeneration, especially in younger patients who are still growing. We demonstrate that a combination of CPC with mesoporous bioactive glass (MBG) particles led to an enhanced degradation in vitro and in a critical alveolar cleft defect in rats. Additionally, to support new bone formation the MBG was functionalized with hypoxia conditioned medium (HCM) derived from rat bone marrow stromal cells. HCM-functionalized scaffolds showed an improved cell proliferation and the highest formation of new bone volume. This highly flexible material system together with the drug delivery capacity is adaptable to patient specific needs and has great potential for clinical translation.展开更多
文摘The aim of this study was to investigate the physiological foramen diameter, shape and distance between physiological and anatomical apex of maxillary and mandibular first and second molars. Accurate knowledge of the physiological foramina morphology; thus, inherent mechanical shaping technical hindrances, is decisive when taking the corresponding root canal final preparation decision. The morphological dimensions of a total of 1 727 physiological foramina were investigated by means of micro-computed tomography. Mean narrow and wide （to a high number, oval） diameters of the physiological foramen were 0.24, 0.22 and 0.33 mm and 0.33, 0.31 and 0.42 mm in mesiobuccal （MB）, distobuccal （DB） and palatal （P） roots in maxillary first molars; 0.24, 0.22 and 0.33 mm and 0.41, 0.33 and 0.44 in MB, DB, and P roots in maxillary second molars. Mandibular first molars showed mean narrow and wide diameters of 0.24 and 0.30 mm and of 0.39 and 0.46 mm in mesial （M） and distal （D） roots; second mandibular molars showed 0.25 and 0.31 mm and 0.47 mm in M and D roots. The mean distance between the physiological foramina and anatomical apex was 0.82, 0.81 and 1.02 mm and 0.54, 0.43 and 0.63 mm in MB, DB and P roots of the maxillary first and second molars, respectively. A mean distance of 0.95 mm （M） and 1.05 mm （D） in the first and 0.78 mm （M） and 0.81 mm （D） in the second mandibular molars was observed. Based on the results obtained, assumable recommendations for final preparation size of the physiological foramen were calculated. However, when taking into consideration, the resulting standard deviations of marginal errors must be cautiously considered when taking a final decision in clinical endodontic treatment.
文摘Objective: To investigate if caries in the pre-treatment early mixed dentition is associated with caries development in the permanent dentition during orthodontic treatment. Material and Methods: We included 41 consecutive patients (29 girls, 12 boys) with a pre-treatment documentation in the mixed (mean age 9.4 years) and a post treatment documentation in the permanent dentition (age 14.9 years) (two-phased treatment time 4.5 (±1.6) years). The DMFT/S indices were calculated. High-risk and low-risk groups were defined according to dmfs + DMFS score before treatment. Results: Initial dmft/s + DMFT/S (SD) was 5.15 (3.60) and 8.32 (6.64);final DMFT/S was 2.76 (2.84) and 3.01 (3.20). The missing (because of decay) second deciduous molars were most powerfully associated with caries increment during treatment, showing significant correlations to second premolars (r = 0.47, p = 0.003), while fillings on second deciduous molars seem to influence the prevalence of fillings on permanent molars (r = 0.44, p = 0.001). The increment at surface level was 2.01 (2.61) in the whole sample and 2.60 (3.81) in the high-risk group (4 boys, 6 girls). Compared to the low-risk group (10 girls), post-treatment caries experience was significantly higher in the high-risk group (p = 0.029). Boys were more at risk than girls (p = 0.005). Conclusions: Children with elevated caries experience in the early mixed dentition are exposed to higher caries risk during orthodontic treatment. Thus, in prevision of treatment, caries should already be assessed in the mixed dentition, so that an extended prophylaxis program can be initiated.
基金This work was founded by the“AO Trauma Deutschland Nachwuchsf¨orderung”(PK)as well as the German Research Foundation(DFGproject no.449121904)(AL,MG).
文摘Calcium phosphate cements (CPC) are currently widely used bone replacement materials with excellent bioactivity, but have considerable disadvantages like slow degradation. For critical-sized defects, however, an improved degradation is essential to match the tissue regeneration, especially in younger patients who are still growing. We demonstrate that a combination of CPC with mesoporous bioactive glass (MBG) particles led to an enhanced degradation in vitro and in a critical alveolar cleft defect in rats. Additionally, to support new bone formation the MBG was functionalized with hypoxia conditioned medium (HCM) derived from rat bone marrow stromal cells. HCM-functionalized scaffolds showed an improved cell proliferation and the highest formation of new bone volume. This highly flexible material system together with the drug delivery capacity is adaptable to patient specific needs and has great potential for clinical translation.
基金supported by the National Key Research and Development Program of China(2022YFC2403200)the National Natural Science Foundation of China(52221006,52293382,52122304,and 52073024)+1 种基金the National High Level Hospital Clinical Research Funding(2023-NHLHCRF-YGJH-ZR-02)Beijing Outstanding Young Scientist Program(BJJWZYJH01201910010024)。
