Objective:To develop a risk prediction model for moderate to severe orthodontic-induced inflammatory root resorption (OIIRR) of maxillary incisors based on cone beam CT (CBCT) radiomics features and clinical characteristics of the orthodontic patients.Methods:Clinical and CBCT data from 101 orthodontic patients treated by the same attending orthodontist in the Department of Orthodontics, Stomatology Hospital of Tianjin Medical University from January 2019 to January 2024 were retrospectively collected. The sample included 42 class Ⅰ patients, 52 class Ⅱ patients and 7 class Ⅲ patients [age: (19.7±6.3) years], and a total of 394 maxillary incisors were analyzed. Potential influencing factors for moderate to severe OIIRR (root volume resorption rate≥10%) were collected from the patients′ CBCT and medical records, including initial age, gender, treatment duration, Angle′s classification, extraction or not, type of orthodontic appliance (fixed or clear aligner), changes in root inclination, root movement distance and direction, pre-treatment cephalometric measurements, pre-treatment root-bone relationship, pre-treatment root length, and pre-treatment radiomics features of the teeth. Univariate analysis was initially performed to screen for factors influencing moderate to severe OIIRR. Subsequently, least absolute shrinkage and selection operator (LASSO) regression, best subset regression, and random forest were used for feature selection to construct the OIIRR risk prediction model. The discrimination, calibration, and net benefit of the three risk prediction models were evaluated, and the optimal model was displayed using a nomogram.Results:LASSO regression identified clinical features including initial age (LASSO coefficient 0.052), treatment duration (LASSO coefficient 0.024), pre-treatment root length (LASSO coefficient -0.023), and vertical root movement distance (LASSO coefficient -0.029). Initial age and treatment duration were positively correlated with the severity of OIIRR, while root length and vertical root movement distance were negatively correlated. A total of 14 radiomics features were identified, including 2 original image features and 12 wavelet features. Best subset regression identified vertical root movement distance as the clinical feature and 7 radiomics features, including 1 original image feature and 6 wavelet features. The random forest model identified 8 wavelet features as important predictors, and all of which were radiomics features. Model performance evaluation showed that the random forest model had the highest discrimination, calibration, and net benefit, making it the optimal model, with radiomics features being the most important predictors.Conclusions:Based on the data from this study, radiomics features were identified as the most important predictors by the optimal model for OIIRR risk prediction. Predicting the occurrence of moderate to severe OIIRR before orthodontic treatment held potential clinical application value.

Objective:To develop a risk prediction model for moderate to severe orthodontic-induced inflammatory root resorption (OIIRR) of maxillary incisors based on cone beam CT (CBCT) radiomics features and clinical characteristics of the orthodontic patients.Methods:Clinical and CBCT data from 101 orthodontic patients treated by the same attending orthodontist in the Department of Orthodontics, Stomatology Hospital of Tianjin Medical University from January 2019 to January 2024 were retrospectively collected. The sample included 42 class Ⅰ patients, 52 class Ⅱ patients and 7 class Ⅲ patients [age: (19.7±6.3) years], and a total of 394 maxillary incisors were analyzed. Potential influencing factors for moderate to severe OIIRR (root volume resorption rate≥10%) were collected from the patients′ CBCT and medical records, including initial age, gender, treatment duration, Angle′s classification, extraction or not, type of orthodontic appliance (fixed or clear aligner), changes in root inclination, root movement distance and direction, pre-treatment cephalometric measurements, pre-treatment root-bone relationship, pre-treatment root length, and pre-treatment radiomics features of the teeth. Univariate analysis was initially performed to screen for factors influencing moderate to severe OIIRR. Subsequently, least absolute shrinkage and selection operator (LASSO) regression, best subset regression, and random forest were used for feature selection to construct the OIIRR risk prediction model. The discrimination, calibration, and net benefit of the three risk prediction models were evaluated, and the optimal model was displayed using a nomogram.Results:LASSO regression identified clinical features including initial age (LASSO coefficient 0.052), treatment duration (LASSO coefficient 0.024), pre-treatment root length (LASSO coefficient -0.023), and vertical root movement distance (LASSO coefficient -0.029). Initial age and treatment duration were positively correlated with the severity of OIIRR, while root length and vertical root movement distance were negatively correlated. A total of 14 radiomics features were identified, including 2 original image features and 12 wavelet features. Best subset regression identified vertical root movement distance as the clinical feature and 7 radiomics features, including 1 original image feature and 6 wavelet features. The random forest model identified 8 wavelet features as important predictors, and all of which were radiomics features. Model performance evaluation showed that the random forest model had the highest discrimination, calibration, and net benefit, making it the optimal model, with radiomics features being the most important predictors.Conclusions:Based on the data from this study, radiomics features were identified as the most important predictors by the optimal model for OIIRR risk prediction. Predicting the occurrence of moderate to severe OIIRR before orthodontic treatment held potential clinical application value.

OBJECTIVES: This study aims to predict the risk of deep caries exposure in radiographic images based on the convolutional neural network model, compare the prediction results of the network model with those of senior dentists, evaluate the performance of the model for teaching and training stomatological students and young dentists, and assist dentists to clarify treatment plans and conduct good doctor-patient communication before surgery. METHODS: A total of 206 cases of pulpitis caused by deep caries were selected from the Department of Stomatological Hospital of Tianjin Medical University from 2019 to 2022. According to the inclusion and exclusion criteria, 104 cases of pulpitis were exposed during the decaying preparation period and 102 cases of pulpitis were not exposed. The 206 radiographic images collected were randomly divided into three groups according to the proportion: 126 radiographic images in the training set, 40 radiographic images in the validation set, and 40 radiographic images in the test set. Three convolutional neural networks, visual geometry group network (VGG), residual network (ResNet), and dense convolutional network (DenseNet) were selected to analyze the rules of the radiographic images in the training set. The radiographic images of the validation set were used to adjust the super parameters of the network. Finally, 40 radiographic images of the test set were used to evaluate the performance of the three network models. A senior dentist specializing in dental pulp was selected to predict whether the deep caries of 40 radiographic images in the test set were exposed. The gold standard is whether the pulp is exposed after decaying the prepared hole during the clinical operation. The prediction effect of the three network models (VGG, ResNet, and DenseNet) and the senior dentist on the pulp exposure of 40 radiographic images in the test set were compared using receiver operating characteristic (ROC) curve, area under the ROC curve (AUC), accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and F1 score to select the best network model. RESULTS: The best network model was DenseNet model, with AUC of 0.97. The AUC values of the ResNet model, VGG model, and the senior dentist were 0.89, 0.78, and 0.87, respectively. Accuracy was not statistically different between the senior dentist (0.850) and the DenseNet model (0.850)(P>0.05). Kappa consistency test showed moderate reliability (Kappa=0.6>0.4, P<0.05). CONCLUSIONS Among the three convolutional neural network models, the DenseNet model has the best predictive effect on whether deep caries are exposed in imaging. The predictive effect of this model is equivalent to the level of senior dentists specializing in dental pulp.
Humans ; Deep Learning ; Neural Networks, Computer ; Pulpitis/diagnostic imaging* ; Reproducibility of Results ; ROC Curve ; Random Allocation

Objective: To study the influence of environmental factors on the two-species biofilm formed by the combinations of Streptococcus oligofermentans (So) with Streptococcus mutans (Sm) and Streptococcus sanguinis (Ss) with Sm so as to evaluate the role of So in maintaining the microecological balance of the oral cavity. Methods: Single-and two-species biofilms were grown on saliva-coated surfaces (glass tube and 96-well plate). Colony-counting method and safranin staining method were used to measure the biofilms formed under various oxygen conditions (aerobic and anaerobic), sucrose conditions (0%, 1% and 5% sucrose concentrations) and pH conditions (5.5, 6.0, 6.5, 7.0, 7.5 and 8.0). Results: Comparing the numbers of Sm in two co-cultures under various conditions, Sm counts in So+Sm group [(7.70±2.46)×10⁸ CFU/ml] were significantly lower than those in Ss+Sm group [(9.00±1.13)×10⁸ CFU/ml] in aerobic environment (P<0.05). Sm counts in So+Sm group [(2.80±0.52)×10⁸ CFU/ml] were also significantly lower than those in the Ss+Sm group [(4.00±1.25)×10⁸ CFU/ml] in anaerobic environment (P<0.05). The Sm counts in So+Sm group [(8.90±0.82)×10⁸ CFU/ml] were significantly higher than those in Ss+Sm group [(7.50±1.73)×10⁸ CFU/ml] in 0% sucrose environment (P<0.05). The Sm counts in So+Sm group [(5.70±2.94)×10⁸ CFU/ml] were significantly lower than those in Ss+Sm group [(10.30±3.21) ×10⁸ CFU/ml] in 1% sucrose environment (P<0.05). The Sm counts in So+Sm group [(6.10±1.71)×10⁸ CFU/ml] were also significantly lower than those in Ss+Sm group [(7.40±1.20)×10⁸ CFU/ml] in 5% sucrose environment (P<0.05). The Sm counts in So+Sm group [(3.50±1.50)×10⁸ CFU/ml] were significantly lower than those in Ss+Sm group [(10.70±2.80)×10⁸ CFU/ml] in pH7.0 environment (P<0.05). Comparing the formation of biofilm after 24 h cultivation, the Sm counts in So+Sm group were significantly lower than those in Ss+Sm group both in aerobic and anaerobic environments (P<0.05). The Sm counts in So+Sm group were significantly higher than those in Ss+Sm group in 0% sucrose environment (P<0.05). The Sm counts in So+Sm group were significantly lower than those in Ss+Sm group in 1% and 5% sucrose and pH 7.0 environments (P<0.05). Both So and Ss had no inhibitory effect on Sm in pH5.5 and pH8.0 environments. Conclusions In the in vitro two-species co-culture systems, So showed stronger inhibitory effects than Ss on Sm and its inhibitory ability might influenced by various environmental factors.

Objective To study the influence of environmental factors on the two?species biofilm formed by the combinations of Streptococcus oligofermentans (So) with Streptococcus mutans (Sm) and Streptococcus sanguinis (Ss) with Sm so as to evaluate the role of So in maintaining the microecological balance of the oral cavity. Methods Single?and two?species biofilms were grown on saliva?coated surfaces (glass tube and 96?well plate). Colony?counting method and safranin staining method were used to measure the biofilms formed under various oxygen conditions (aerobic and anaerobic), sucrose conditions (0%, 1% and 5% sucrose concentrations) and pH conditions (5.5, 6.0, 6.5, 7.0, 7.5 and 8.0). Results Comparing the numbers of Sm in two co?cultures under various conditions, Sm counts in So+Sm group [(7.70 ± 2.46)× 108 CFU/ml] were significantly lower than those in Ss+Sm group [(9.00 ± 1.13)×108 CFU/ml] in aerobic environment (P<0.05). Sm counts in So+Sm group [(2.80±0.52)×108 CFU/ml] were also significantly lower than those in the Ss+Sm group [(4.00±1.25)×108 CFU/ml] in anaerobic environment (P<0.05). The Sm counts in So+Sm group [(8.90±0.82)×108 CFU/ml] were significantly higher than those in Ss+Sm group [(7.50± 1.73)×108 CFU/ml] in 0% sucrose environment (P<0.05). The Sm counts in So+Sm group [(5.70 ± 2.94)× 108 CFU/ml] were significantly lower than those in Ss+Sm group [(10.30±3.21)×108 CFU/ml] in 1% sucrose environment (P<0.05). The Sm counts in So+Sm group [(6.10±1.71)×108 CFU/ml] were also significantly lower than those in Ss+Sm group [(7.40±1.20)×108 CFU/ml] in 5% sucrose environment (P<0.05). The Sm counts in So+Sm group [(3.50 ± 1.50)×108 CFU/ml] were significantly lower than those in Ss+Sm group [(10.70±2.80)×108 CFU/ml] in pH7.0 environment (P<0.05). Comparing the formation of biofilm after 24 h cultivation, the Sm counts in So+Sm group were significantly lower than those in Ss+Sm group both in aerobic and anaerobic environments (P<0.05). The Sm counts in So+Sm group were significantly higher than those in Ss+Sm group in 0% sucrose environment (P<0.05). The Sm counts in So+Sm group were significantly lower than those in Ss+Sm group in 1% and 5% sucrose and pH 7.0 environments (P<0.05). Both So and Ss had no inhibitory effect on Sm in pH5.5 and pH8.0 environments. Conclusions In the in vitro two?species co?culture systems, So showed stronger inhibitory effects than Ss on Sm and its inhibitory ability might influenced by various environmental factors.

Objective:To evaluate the fracture resistance of roots instrumented with Reciproc,WaveOne,ProTaper and BLX respectively.Methods:50 extracted maxillary and 50 extracted mandibular anterior teeth were selected and randomly divided into 5 groups respectively(n =10).The teeth in the 4 experimental groups were instrumented by 4 the instruments respectively and the teeth in the control group were not treated.A vertical load was applied to the roots and the fracture load for each sample was recorded.The data were analyzed with SPSS 19.0 software.Results:After preparition the fracture load of the experimental groups was lower than that of the control (P ＜ 0.05),between the Reciproc and WaveOne groups (P ＞ 0.05),between ProTaper and BLX groups for maxi teeth (P ＞0.05),for mandibular teeth(P ＜ 0.05).The fracture load of Reciproc and WaveOne was higher than that of ProTaper and BLX(P ＜0.05).After making same taper shape using same root canal instrument,the mandibular anterior teeth had lower fracture resistances than the maxillary anterior teeth (P ＜ 0.05).Conclusion:Single-file reciprocating systems groups may decrease less fracture resistance than full-sequence rotary systems.with or without instrumentation,maxillary anterior teeth have higher fracture resistance than mandibular anterior teeth.

Objective To evaluate antibacterial and residual antimicrobial activities of five root canal irrigants including Qmix,MTAD(mixture of a tetracycline isomer,an acid,and a detergent),0.2％ cetrimide(CTR),2％chlorhexidine(CHX) and 17％ethylene diaminetetraacetic acid(EDTA) and to find the most optimal final irrigants for using in root canal therapy.Methods The standard enterococcus infection models were built up in 100 single rooted incisors with single canal.Totally 30 teeth were selected by using random number tablefor detecting the quality of the bacteria model.Crown-down technique with rotary ProTaper system was used to prepare the root canals.Then the teeth were randomly divided into seven groups of which five groups were irrigated with five different irrigants respectively,one group was irrigated with distilled water(distilled water group) and one group was no-irrigation group.Each tooth was sectioned into three parts:apical 1/3,middle 1/3 and coronal 1/3.After irrigation,specimenswere cultivated from day 0 to day 14.All statistical analyses were performed by means of SPSS 17.0 software.Chi-squared test was used to evaluate antibacterial activities.Generalized estimating equations was used to evaluate residual antimicrobial activities.Results All samples rinsed with Qmix,MTAD,CTR,CHX were bacteria-free in 0 day.The samples rinsed with EDTA and distilled water had no bacteria in 7 coronal sections,6 middle sections and 9 apical sections,respectively.The results of Qmix,MTAD,CTR and CHX groups showed significant difference when compared with that of distilled water,EDTA and control groups(P＜0.05).Residual antimicrobial resultsin EDTA,distilled water,no-irrigation groups showed significant differences compared with that of Qmix,MTAD,CTR,CHX groups according to pairwise comparison(P＜O.05) on day 1,2 and 3.There was no significant difference between the other two groups(P＞0.05).Antimicrobial properties on the coronal 1/3 and apical 1/3,middle 1/3 and apical 1/3 showed significant difference(P＜0.05) while middle 1/3 and coronal 1/3 showed no significant difference(P＞0.05).Conclusions Qmix,MTAD,CTR and CHX had an antimicrobial activity,but could not destroy Enterococcus faecalis completely.Antimicrobial activity in coronal 1/3 was better than in apical 1/3.Qmix,MTAD,CTR and CHX had a residual antimicrobial activity with various lasting times.The lasting time of residual antimicrobial activity was as follow:MTAD＞ CTR＞Qmix＞CHX.EDTA had no antibacterial and residual antimicrobial activities.

BACKGROUND:In root canal preparation, the clearance effect of sodium hypochlorite for root canal irrigation on the smear layer is associated with the contact time and contact area of irrigation fluid, the amount of irrigation fluid, irrigation fluid temperature, irrigation fluid concentration, flushing methods and so on. OBJECTIVE:To investigate the clearance effect of 3% sodium hypochlorite on the smear layer of root canal under different flushing methods, flushing temperature and flushing time. METHODS:Totaly 180 isolated front teeth with single root were colected and root canal preparation was conducted using motorized ProTaper. The root canal was flushed with 3% sodium hypochlorite. According to different flushing methods, these root canals were randomly and evenly divided into root canal active flushing group, passive ultrasound swished group and side opening flushing needle group. According to the flushing temperature and the flushing time after replacing a file, each group was randomly divided into six subgroups: 20℃ 30 seconds group, 20℃ 60 seconds group, 37 ℃ 30 se group. The clearance effect on the smear layer of root canal was observed using scanning electron microscope. RESULTS AND CONCLUSION:The general clearance effect on the smear layer in the root canal active flushing group was better than that in the passive ultrasound swished group and side opening flush acupuncture group (P< 0.05). At the same time, the clearance effect on the smear layer in the 60℃ group was better that that in the 37 ℃ group and 20℃group (P < 0.05). At a certain temperature, the clearance effect on the smear layer in 60 seconds group was better than that in the 30 seconds group (P < 0.05). The clearance effect on the smear layer in the 1/3 root cap zone was better than that in the 1/3 root and 1/3 apical root zone (P < 0.05). These results show that the best clearance effect on the smear layer can be achieved as folows: 3% sodium hypochlorite irrigation at 60℃ for 60 seconds.

Objective:To investigate the inhibition of Streptococcus oligofermentans(So)on Streptococcus mutans(Sm)and the hydro-gen peroxide(H2 O2 )producibility by So under different sucrose concentration environment.Methods:The inhibition of So on Sm was observed by plating method under different sucrose concentration environment.The initial synthesis rates and production of H2 O2 by So were determined by 4-aminoantipyine-horseradish peroxidase method.Results:Under 500 mmol/L of H2 O2 ,the inhibition of So on Sm was not observed.Under the other sucrose concentration environment,the inhibition of So on Sm was as following:50 mmol/L >0 mmol/L and 1 mmol/L(P <0.05);the initial synthesis rates of H2 O2 by So under different sucrose concentrations were as following:50 mmol/L >0 mmol/L and 1 mmol/L >500 mmol/L(P <0.05);the total production of H2 O2 by So:0 mmol/L and 1 mmol/L >50 mmol/L >500 mmol/L(P <0.05).When So was inoculated before Sm,the inhibition of So on Sm was stronger than that when the two species were inoculated at the same time.Conclusion:The capability of the inhibition of So on Sm and the production of H2 O2 by So are influenced by sucrose concentration.

Objective:To compare the efficacy of six different irrigation techniques on smear layer removal.Methods:60 single-rooted teeth were prepared.The root canals were irrigated with NaOCl at 20 ℃ or 60 ℃,and activated with side-vented needle,pas-sive ultrasonic irrigation (PUI)and EndoActivator (EA)irrigation techniques respectively.Then teeth were randomly divided into 6 groups(n =1 0):20 ℃-PUI group,20 ℃-EA group,20 ℃control group,60 ℃-PUI group,60 ℃-EA group and 60 ℃ control group.Smear layer was observed under thermal field emission scanning electron microscope(FE-SEM)and scored according to the cri-teria specified by Hulsmann M.Results:The smear layer removal effect in 60 ℃ groups was better than that in 20 ℃ groups (P <0.05),and better in 20 ℃-EA and 20 ℃-PUI groups than in 20 ℃ control group(P <0.05).Conclusion:The temperature of NaOCl is the main factor influencing the smear layer removal,NaOCl at 60 ℃ is more effective than that at 20 ℃.