Screw-and-cement-retained prosthesis versus cement-retained prosthesis: Which is more appropriate for the upper premolar area?

Background/purpose: The narrow alveolar ridge in the maxillary premolars area limits the angle of implant placement and the shape of the prosthesis. The aim of this study was to evaluate which implant prosthesis, screw-and-cement-retained prosthesis (SCRP) or cement-retained prosthesis (CRP), was more suitable for the maxillary premolar area. Materials and methods: We conducted virtual implantation on 58 implant images from 47 patients obtained using cone beam computed tomography (CBCT). The width and buccal inclination of the alveolar bone, the angulation of the implant fixture, and the angulation of abutment were measured and calculated. Results: We determined that SCRP was feasible in 52% and 78.8% of first and second premolar areas, respectively. There was a positive relationship between the feasibility of SCRP and the premolar region in general (P = 0.031), although SCRP was more likely to be a possibility in the second premolar area. On multiple logistic regression analysis, the difference in the angle between the axis of the prosthesis and the axis of the alveolar bone (RA) was significantly associated with the type of prosthesis (P = 0.001). The RA was significantly higher for CRP implants (OR = 1.885; 95% CI: 1.31 to 2.70). Conclusion: SCRP is not always feasible in the maxillary premolar area, especially in the first premolar area. If the difference between the angle of the axis of the prosthesis and the axis of the alveolar bone is large, it may be necessary for the clinician to consider CRP in the treatment planning stage.

Association between sleeping time and temporomandibular disorders in a sample of the South Korean population.

Objective: This study investigated the relationship between sleeping time and temporomandibular disorders (TMDs).Methods: This study used data from the Fifth Korea National Health and Nutrition Examination Survey from 2010 to 2011. The final sample size consisted of 11,782 adults aged ≥19 years. Logistic regression analysis was performed to assess the relationship between sleeping time and TMD.Results: The adjusted odds ratios of the TMD group were 1.421 (1.067, 1.892) (Model 1), 1.388 (1.028, 1.873) (Model 2), and 1.360 (1.012, 1.826) (Model 3) for subjects with sleeping time ≤5 hours (p < 0.05) and 1.317 (0.992, 1.748) (Model 1), 1.358 (1.01, 1.827) (Model 2), and 1.352 (0.977, 1.872) (Model 3) for subjects with sleeping time ≥9 hours (p < 0.05).Conclusion: Sleeping time ≤5 hours and ≥9 hours were associated with an increased rate of TMD.

A study on the morphologic change of palatal alveolar bone shape after intrusion and retraction of maxillary incisors.

The purpose of this study is to evaluate the changes in the palatal alveolar bone thickness and find the factors related to the resorption of the palatal alveolar bone caused by tooth movement after the maxillary incisors were retracted and intruded during orthodontic treatment. The study group comprised of 33 skeletal Class II malocclusion patients who underwent extraction for orthodontic treatment. Palatal alveolar bone thickness changes and resorption factors were identified and analyzed. The changes of maxillary central incisors and palatal alveolar bone thickness were measured, and the corresponding sample t test was performed using SPSS (IBM SPSS version 22). The amount of palatal alveolar bone resorption was measured and various parameters were analyzed to determine which factors affected it. Correlation analysis adopting the amount of palatal alveolar bone resorption as a dependent variable demonstrated that the SNB, mandibular plane angle, and the inclination of the maxillary central incisor were significantly correlated with before treatment. On the other hand, mandibular plane angle, angle of convexity, the inclination of the upper incisor, and the occlusal plane (UOP, POP) were significantly correlated with post-treatment. In addition, the variables related to palatal contour (PP to PAS, SN to PAS, palatal surface angle) and occlusal planes (UOP/POP) were significantly correlated with the difference in palatal bone resorption. During initial diagnosis, high angle class II with normal upper incisor inclination can be signs of high-risk factors. In addition, maintaining the occlusal plane during treatment helps to prevent palatal bone loss.

Investigation of the association between orthodontic treatment and temporomandibular joint pain and dysfunction in the South Korean population.

OBJECTIVE: This study investigated the relationship between orthodontic treatment and temporomandibular disorders (TMD) in South Korean population. METHODS: This study obtained data from the 2012 Korean National Health and Nutrition Examination Survey. The final sample size was 5,567 participants who were ≥ 19 years of age. Logistic regression analysis was performed to evaluate the relationship between orthodontic treatment and TMD. RESULTS: Participants who underwent orthodontic treatment showed higher educational level, lower body mass index, reduced chewing difficulty, and reduced speaking difficulty. The adjusted odds ratios (ORs) and their 95% confidence intervals (CIs) for orthodontic treatment and TMD were 1.614 (1.189-2.190), 1.573 (1.162-2.129) and 1.612 (1.182-2.196) after adjusting for age, sex and psychosocial factors. Adjusted ORs and their 95% CIs for orthodontic treatment and clicking were 1.778 (1.289-2.454), 1.742 (1.265-2.400) and 1.770 (1.280-2.449) after adjusting for confounding factors. However, temporomandibular joint pain and functional impairment was not associated with orthodontic treatment. CONCLUSIONS: Temporomandibular joint pain and dysfunction was not associated with orthodontic treatment.

Association between dental health and obstructive coronary artery disease: an observational study.

BACKGROUND: The association between dental health and coronary artery disease (CAD) remains a topic of debate. This study aimed to investigate the association between dental health and obstructive CAD using multiple dental indices. METHODS: Eighty-eight patients (mean age: 65 years, 86% male) were prospectively enrolled before undergoing coronary CT angiography (n = 52) or invasive coronary angiography (n = 36). Obstructive CAD was defined as luminal stenosis of ≥50% for the left main coronary artery or ≥ 70% for the other epicardial coronary arteries. All patients underwent thorough dental examinations to evaluate 7 dental health indices, including the sum of decayed and filled teeth, the ratio of no restoration, the community periodontal index of treatment needs, clinical attachment loss, the total dental index, the panoramic topography index, and number of lost teeth. RESULTS: Forty patients (45.4%) had obstructive CAD. Among the 7 dental health indices, only the number of lost teeth was significantly associated with obstructive CAD, with patients who had obstructive CAD having significantly more lost teeth than patients without obstructive CAD (13.08 ± 10.4 vs. 5.44 ± 5.74, p < 0.001). The number of lost teeth was correlated with the number of obstructed coronary arteries (p < 0.001). Multiple binary logistic regression analysis revealed that having ≥10 lost teeth was independently associated with the presence of obstructive CAD (odds ratio: 8.02, 95% confidence interval: 1.80-35.64; p = 0.006). CONCLUSIONS: Tooth loss was associated with the presence of obstructive CAD in patients undergoing coronary evaluation. Larger longitudinal studies are needed to determine whether there is a causal relationship between tooth loss and CAD.

When do we need more than local compression to control intraoral haemorrhage?

OBJECTIVES: The aims of this study were to determine the effectiveness of local compression in patients presenting to the emergency room with intraoral bleeding and to identify when complex haemostatic measures may be required. MATERIALS AND METHODS: Five hundred forty patients who had experienced intraoral haemorrhage were retrospectively reviewed. The outcome variable was the haemostasis method used, i.e., simple (local compression with gauze) or complex (an alternative method after local compression has failed). Predictor variables were sex, age, American Society of Anesthesiologists (ASA) class, hepatic cirrhosis, bleeding disorder, use of antithrombotic agents, and site/cause of haemorrhage. RESULTS: The mean patient age was 48.9±23.9 years, 53.5% were male, 42.8% were ASA class II or higher, and 23.7% were taking antithrombotic agents. Local compression was used most often (68.1%), followed by local haemostatic agents, sutures, systemic tranexamic acid or blood products, and electrocautery. The most common site of bleeding was the gingiva (91.7%), and the most common cause was tooth extraction (45.7%). Risk factors for needing a complex haemostasis method were use of antithrombotic agents (odds ratio 2.047, P=0.009) and minor oral surgery (excluding extraction and implant procedures; odds ratio 6.081, P=0.001). CONCLUSION: A haemostasis method other than local compression may be needed in patients taking antithrombotic agents or having undergone minor oral surgery.

C-shaped root canals of mandibular second molars in a Korean population: a CBCT analysis.

OBJECTIVES: The purpose of this study was to investigate the C-shaped root canal anatomy of mandibular second molars in a Korean population. MATERIALS AND METHODS: A total of 542 teeth were evaluated using cone-beam computed tomography (CBCT). The canal shapes were classified according to a modified version of Melton's method at the level where the pulp chamber floor became discernible. RESULTS: Of the 542 mandibular second molars, 215 (39.8%) had C-shaped canals, 330 (53%) had 3 canals, 17 (3.3%) had 2 canals, 12 (2.2%) had 4 canals, and 8 (1.7%) had 1 canal. The prevalence of C-shaped canals was 47.8% in females and 28.4% in males. Seventy-seven percent of the C-shaped canals showed a bilateral appearance. The prevalence of C-shaped canals showed no difference according to age or tooth position. Most teeth with a C-shaped canal system presented Melton's type II (45.6%) and type III (32.1%) configurations. CONCLUSIONS: There was a high prevalence of C-shaped canals in the mandibular second molars of the Korean population studied. CBCT is expected to be useful for endodontic diagnosis and treatment planning of mandibular second molars.

Fracture patterns and causes in the craniofacial region: an 8-year review of 2076 patients.

BACKGROUND: For proper recovery from craniofacial fracture, it is necessary to establish guidelines based on trends. This study aimed to analyze the patterns and causes of craniofacial fractures. METHODS: This retrospective study analyzed patients who underwent surgery for craniofacial fractures between 2010 and 2017 at a single center. Several parameters, including time of injury, region and cause of fracture, alcohol intoxication, time from injury to surgery, hospitalization period, and postoperative complications, were evaluated. RESULTS: This study analyzed 2708 fracture lesions of 2076 patients, among whom males aged 10 to 39 years were the most numerous. The number of patients was significantly higher in the middle of a month. The most common fractures were a nasal bone fracture. The most common causes of fracture were ground accidents and personal assault, which tended to frequently cause more nasal bone fracture than other fractures. Traffic accidents and high falls tended to cause zygomatic arch and maxillary wall fractures more frequently. Postoperative complications-observed in 126 patients-had a significant relationship with the end of a month, mandible or panfacial fracture, and traffic accidents. CONCLUSIONS: The present findings on long-term craniofacial fracture trends should be considered by clinicians dealing with fractures and could be useful for policy decisions.

Risk factor analysis of additional administration of sedative agent and patient dissatisfaction in intravenous conscious sedation using midazolam for third molar extraction.

OBJECTIVES: The primary purpose of this study was to investigate the factors related with additional administration of sedative agent during intravenous conscious sedation (IVS) using midazolam (MDZ). The secondary purpose was to analyze the factors affecting patient satisfaction. MATERIALS AND METHODS: Clinical data for 124 patients who had undergone surgical extraction of mandibular third molar under IVS using MDZ were retrospectively investigated in this case-control study. The initial dose of MDZ was determined by body mass index (BMI) and weight. In the case of insufficient sedation at the beginning of surgery, additional doses were injected. During surgery, peripheral oxygen saturation, bispectral index score (BIS), heart rate, and blood pressure were monitored and recorded. The predictor variables were sex, age, BMI, sleeping time ratio, dental anxiety, Pederson scale, and initial dose of MDZ. The outcome variables were additional administration of MDZ, observer's assessment of alertness/sedation, intraoperative amnesia, and patient satisfaction. Descriptive statistics were computed, and the P-value was set at 0.05. RESULTS: Most patients had an adequate level of sedation with only the initial dose of MDZ and were satisfied with the treatment under sedation; however, 19 patients needed additional administration, and 13 patients were unsatisfied. In multivariable logistic analysis, lower age (odds ratio [OR], 0.825; P=0.005) and higher dental anxiety (OR, 5.744; P=0.003) were related to additional administration; lower intraoperative amnesia (OR, 0.228; P=0.002) and higher BIS right before MDZ administration (OR, 1.379; P=0.029) had relevance to patient dissatisfaction. CONCLUSION: The preoperative consideration of age and dental anxiety is necessary for appropriate dose determination of MDZ in the minor oral surgery under IVS. The amnesia about the procedure affects patient satisfaction positively.

Association between orthodontic treatment and periodontal diseases: Results from a national survey.

OBJECTIVE: To investigate the association between orthodontic treatment and periodontitis in a nationally representative sample of South Korea. MATERIALS AND METHODS: Data from the Fifth and Sixth Korean National Health and Nutrition Examination Survey (KNHANES V, VI-1, and VI-2), conducted from 2012 to 2014, were used in this study. The final sample size consisted of 14,693 adults aged ≥19 years. Logistic regression analysis was performed to assess the association between orthodontic treatment and periodontitis. RESULTS: The orthodontic treatment group exhibited a lower prevalence of periodontitis compared with the nonorthodontic treatment group. The adjusted odds ratios for periodontitis in subjects with a history of orthodontic treatment compared with those with no history of orthodontic treatment were 0.553, 0.614, and 0.624, when adjusted for various confounding variables (P < .0001). The subjects with periodontitis were of higher age, body mass index, waist circumference, and white blood cell counts compared with the subjects without periodontitis regardless of history of orthodontic treatment. CONCLUSIONS: History of orthodontic treatment was associated with a decreased rate of periodontitis.

Failure of Orthodontic Mini-implants by Patient Age, Sex, and Arch; Number of Primary Insertions; and Frequency of Reinsertions After Failure: An Analysis of the Implant Failure Rate and Patient Failure Rate.

This study aimed to analyze and compare the failure rate of orthodontic mini-implants (OMIs) in terms of the number of implants (implant failure rate [IFR]) and patients (patient failure rate [PFR]) according to the age, sex, and arch of the patients, the number of primary insertions, and frequency of reinsertions after failure. A total of 394 OMIs (1.2 mm in diameter; 7.0 mm in length) were inserted in 125 patients (24 male and 101 female, mean age 21.95 ± 7.60 years). IFR and PFR were evaluated according to the age and sex of the patient, the number of primary insertions, and the frequency of reinsertions after failure. PFR was 40.08% and IFR was 18.27% after the first insertions. PFR was higher than IFR regardless of the number of OMIs inserted. IFR increased with an increase in the frequency of reinsertions, reaching 66.67% after the fourth insertion, whereas PFR decreased to 25.00% after the second insertion and to 66.67% after the third and fourth insertions. The overall PFR and IFR were 40.80% and 19.29%, respectively. Although male patients, young patients, and location in the mandible showed higher PFR and IFR, there were no significant differences between PFR and IFR according to the sex, age, or arch. PFR was higher than IFR in this study, indicating that the treatment process could be more strongly affected by PFR than IFR. The failure rate can increase with the frequency of OMI reinsertions after failure. Sex, age, and arch may have no correlation with primary or recurrent OMI failure.

Charting microbial phenotypes in multiplex nanoliter batch bioreactors.

High-throughput growth phenotyping is receiving great attention for establishing the genotype-phenotype map of sequenced organisms owing to the ready availability of complete genome sequences. To date, microbial growth phenotypes have been investigated mostly by the conventional method of batch cultivation using test tubes, Erlenmeyer flasks, or the recently available microwell plates. However, the current batch cultivation methods are time- and labor-intensive and often fail to consider sophisticated environmental changes. The implementation of batch cultures at the nanoliter scale has been difficult because of the quick evaporation of the culture medium inside the reactors. Here, we report a microfluidic system that allows independent cell cultures in evaporation-free multiplex nanoliter reactors under different culture conditions to assess the behavior of cells. The design allows three experimental replicates for each of eight culture environments in a single run. We demonstrate the versatility of the device by performing growth curve experiments with Escherichia coli and microbiological assays of antibiotics against the opportunistic pathogen Pseudomonas aeruginosa. Our study highlights that the microfluidic system can effectively replace the traditional batch culture methods with nanoliter volumes of bacterial cultivations, and it may be therefore promising for high-throughput growth phenotyping as well as for single-cell analyses.