No increased risk of osteonecrosis of the jaw in osteoporotic patients with dental implants: a nationwide cohort study.

OBJECTIVES: The occurrence of implant-associated osteonecrosis of the jaw (ONJ) has been reported in osteoporotic patients, particularly in association with bisphosphonate therapy. This study aimed to investigate the risk of implant surgery and implant presence for ONJ occurrence in osteoporotic patients longitudinally. METHODS: Based on Korean National Health Information Database, subjects over the age of 65 who were diagnosed with osteoporosis between July 2014 and December 2016 were included. The implant group included subjects who had undergone dental implant surgery between January 2017 and December 2017, while the control group included those who had no history of dental implants. The primary outcome was the occurrence of ONJ, and the date of final follow-up was December 2020. RESULTS: A total of 332,728 subjects with osteoporosis were included in the analysis: 83,182 in the implant group and 249,546 in the control group. The risk of ONJ among those who had undergone implant surgery (risk of implant surgery-associated ONJ) was not higher than that among those without implant surgery. The risk of ONJ among those with implants (risk of implant presence-associated ONJ) was lower than that among those without implants. Even in subjects with a history of bisphosphonates, steroids, periodontitis, or tooth extraction, those who had undergone implant surgery or had implants did not have a higher ONJ risk than those who had not undergone surgery or did not have implants; rather, they showed a lower risk. CONCLUSIONS: The results may suggest that dental implants are not associated with an increased risk of ONJ. A further study on whether dental implants are associated with lower ONJ risk is needed. CLINICAL RELEVANCE: Dental implants did not increase the risk of ONJ development in osteoporotic patients, even with a history of bisphosphonates. This may suggest that the risk profiles for ONJ occurrence between selective insertion of dental implants and other dentoalveolar surgery associated with infectious conditions are different.

Presurgical Reduction of the Cleft Palate: Serendipitous Benefit of the Stanford Orthodontic Airway Plate Treatment (SOAP) for Infants with Robin Sequence.

OBJECTIVE: Narrowing of the palatal cleft is often observed in infants with Robin sequence (RS) treated with the Stanford Orthodontic Airway Plate treatment (SOAP) even though SOAP is utilized primarily to establish airway patency. The current study quantified dimensional changes of the cleft palate (CP) in infants with RS treated with SOAP. DESIGN: A retrospective chart review. PATIENTS: Infants with RS and CP who completed SOAP and had maxillary arch models at both pre- and post-treatment time points at a single tertiary referral hospital between September 2019 and July 2023. SETTING AND OUTCOME MEASURE: Maxillary arch models were measured and analyzed using Bivariate statistical analysis. RESULTS: Seventeen infants were included in the study. The median age (min, max) was 6.7 weeks (1.1, 21.9) at pre-treatment and 26.6 weeks (18.7, 37.0) at post-treatment. The median Obstructive Apnea Hypopnea Index was 36.2 events/hour (8.1, 103.1) at pre-treatment and 4.1 events/hour (1.9, 8.6) at post-treatment. The pre-treatment width of CP decreased by an average (± standard diviation) of 6.37 mm (± 3.55, p < 0.001) at post-treatment. The ratio of the posterior cleft width to the total maxillary arch width decreased from 40% (± 9.1) at pre-treatment to 22% (± 11) at post-treatment (p < 0.001). CONCLUSION: The dimensions of CP reduced significantly during SOAP in infants with RS and CP treated for their severe upper airway obstruction. The findings highlight a potential benefit of SOAP that may contribute favorably to the palate repair surgery.

Fabrication of Chitosan/PEGDA Bionanocomposites for Enhanced Drug Encapsulation and Release Efficiency.

Drug delivery systems (DDS) have evolved in the last decades with the development of hydrogels and particles. However, challenges such as high systemic uptake, side effects, low bioavailability, and encapsulation efficiency continue to be significant hurdles faced by such DDSs. Particles and hydrogels can be specifically designed for targeted DDSs to mitigate some of these problems. This study developed chitosan (Cs) particles (Ps) and composite films using poly(ethylene glycol) diacrylate (PEGDA) as a copolymer to encapsulate gentamicin (GtS) for drug delivery. We demonstrated that lysozyme degrades the chitosan ß-1,4 glycosidic bonds to release GtS. PEGDA increased drug encapsulation efficiency by shielding the repelling forces of like charges between Cs and GtS. The data show that PEGDA does not hinder enzymatic degradation while increasing drug encapsulation efficiency and producing more homogeneous particles. Additionally, we utilized Michael's reaction to cross-link Cs, CsPs, and PEGDA to produce a film designed for drug delivery. The film is an anchor for CsPs to prevent premature drug release. The cross-linking of Cs and PEGDA does not affect lysozyme activity, and CsPs could successfully release GtS without affecting GtS activity.

Effects of daily versus weekly teriparatide for medication-related osteonecrosis of the jaw: A case-control study.

INTRODUCTION: Medication-related osteonecrosis of the jaw (MRONJ) is uncommon but can result in severe destruction of the jaw. This case-control study investigated the therapeutic effects of daily or weekly administration of teriparatide in the management of MRONJ using a cohort for osteonecrosis of the jaw. METHODS: Patients who were diagnosed with MRONJ and consented to teriparatide administration were assigned either to a group of daily injection or of weekly injection and completed a 4-week course of injection preoperatively and at least an 8-week course postoperatively. The control group received either the intraoperative rhBMP treatment (CG_BMP) or no additional perioperative treatment (CG_noBMP). The state of MRONJ was evaluated 2 months (T1) and 6 months (T2) postoperatively for all participants. RESULTS: Either group of daily injection (8.35 weeks ± 1.58; n = 17) or weekly injection (9.17 ± 3.79; n = 12) showed significantly faster healing than those of CG_BMP (14.40 ± 6.08; n = 25) or CG_noBMP (15.79 ± 9.79; n = 39). MRONJ was resolved completely in 24 out of 29 participants who completed the course of teriparatide injections, whereas 46.9% of CG showed delayed resolution. Multiple regression analysis indicated 7.50 times (95% CI, 1.77-31.82) more likelihood of complete resolution of MRONJ for participants with teriparatide injections. CONCLUSION: A course of daily or weekly administration of teriparatide injections may improve treatment outcomes for patients with MRONJ.

Effectiveness of individualized 3D titanium-printed Orthognathic osteotomy guides and custom plates.

BACKGROUND: Computer-aided design/manufacturing (CAD/CAM) technology was developed to improve surgical accuracy and minimize errors in surgical planning and orthognathic surgery. However, its accurate implementation during surgery remains a challenge. Hence, we compared the accuracy and stability of conventional orthognathic surgery and the novel modalities, such as virtual simulation and three-dimensional (3D) titanium-printed customized surgical osteotomy guides and plates. METHODS: This prospective study included 12 patients who were willing to undergo orthognathic surgery. The study group consisted of patients who underwent orthognathic two-jaw surgery using 3D-printed patient-specific plates processed by selective laser melting and an osteotomy guide; orthognathic surgery was also performed by the surgeon directly bending the ready-made plate in the control group. Based on the preoperative computed tomography images and intraoral 3D scan data, a 3D virtual surgery plan was implemented in the virtual simulation module, and the surgical guide and bone fixation plate were fabricated. The accuracy and stability were evaluated by comparing the results of the preoperative virtual simulation (T0) to those at 7 days (T1) and 6 months (T2) post-surgery. RESULT: The accuracy (ΔT1‒T0) and stability (ΔT2‒T1) measurements, using 11 anatomical references, both demonstrated more accurate results in the study group. The mean difference of accuracy for the study group (0.485 ± 0.280 mm) was significantly lower than in the control group (1.213 ± 0.716 mm) (P < 0.01). The mean operation time (6.83 ± 0.72 h) in the control group was longer than in the study group (5.76 ± 0.43 h) (P < 0.05). CONCLUSION: This prospective clinical study demonstrated the accuracy, stability, and effectiveness of using virtual preoperative simulation and patient-customized osteotomy guides and plates for orthognathic surgery.

Serum biomarkers for bisphosphonate-related osteonecrosis of the jaw: a prospective clinical study.

In this prospective study, serum levels of 12 possible biomarkers were compared between osteonecrosis of the jaw (ONJ) and control groups, before and after dentoalveolar surgery. The results suggest that patients with abnormal serum levels of specific biomarkers should be monitored closely for the prevention and early diagnosis of ONJ. INTRODUCTION: Bisphosphonate-related osteonecrosis of the jaw (ONJ) is an adverse effect of long-term bisphosphonate therapy. This study aimed to identify bone biomarkers for ONJ risk assessment and diagnosis. METHODS: This prospective study included patients with histories of bisphosphonate therapy without current ONJ who were in need of dentoalveolar surgery of the jaw area. Serum levels of 12 possible bone markers, selected based on their involvement in ONJ pathogenesis, were compared between ONJ and control groups before dentoalveolar surgery (T0), at 8 postoperative weeks (T1), and at 4 months after diagnosis(T2). RESULTS: Seventy-six patients who met the inclusion criteria were included in the study; 33 were assigned to the ONJ group, and 43 patients without ONJ signs or symptoms after dentoalveolar surgery were assigned to the control group. In the ONJ group, at both T0 and T1, the mean tartrate-resistant acid phosphatase isoform 5b (TRACP 5b) levels were significantly lower and the mean Dickkopf-related protein 1 (DKK1) levels were significantly higher than the corresponding values for the control group. Linear mixed model analysis revealed significant group effects over time for serum TRACP 5b and DKK1 after adjusting for demographic, pharmacological, and diagnostic variables. Lower serum levels of TRACP 5b under a specified cut-off value (≤ 2.899 U/L) at T0 indicated a 20.40-fold increased risk of ONJ development. CONCLUSION: Patients with abnormally low serum levels of TRACP 5b and high serum levels of DKK1 should be monitored closely before and after dentoalveolar surgery for the prevention and early diagnosis of ONJ.

Covalent Crosslinking of Colloidal Cellulose Nanocrystals for Multifunctional Nanostructured Hydrogels with Tunable Physicochemical Properties.

Cellulose nanocrystals (CNCs) have shown promise for the development of multifunctional materials for many research communities, ranging from bioresource engineering and biomedical engineering to materials science and engineering. However, accessible hydroxyl (OH) groups on the surface of colloidal CNCs at the (11̅0)ß/(100)α and (110)ß/(010)α facets and the intermolecular hydrogen bonding (H-bonds) between these OH groups account for the instability of self-assembled CNC structures in moist environments, limiting their practical uses to dry media. In this work, accessible OH groups of CNCs were crosslinked using two crosslinkers, that is, glutaraldehyde (GA) and epichlorohydrin (EC), to form nanoparticle-based hydrogels with tunable physicochemical properties. The intensity of the intermolecular H-bonds was controlled by the type and concentration of crosslinkers as well as the CNC concentration. Rheological analyses through the loss tangent were used to determine the degree of crosslinking with maximal values beyond 90%. Fourier-transform infrared spectroscopy demonstrated that H-bond intensity was inversely proportional to the degree of crosslinking for both GA and EC, indicating a dissimilar crosslinking mechanism for GA and EC in acidic and alkaline pH conditions, respectively. Atomic force microscopy and wettability analyses showed a significant increase in the surface roughness from 3.2 ± 0.41 nm (pure CNC) to 31.5 ± 1.08 nm (CNCs crosslinked by GA) and 23.8 ± 0.14 nm (CNCs crosslinked by EC) and water contact angle from 13° (pure CNC) to 108° (CNCs crosslinked by GA) and 104° (CNCs crosslinked by EC). Moreover, optimum water absorption values were found at 157.67 ± 2.01 g and 173.59 ± 1.26 g of water for 1 g of freeze-dried hydrogels for 10% GA and 1% EC, respectively. The results aligned with reaction conditions that led to maximal degrees of crosslinking and indicated the transformation of surface chemistry from a hydrophilic to a hydrophobic network as well as tunable topology and aqueous stability of self-assembled structures made from crosslinked CNCs. This technology demonstrated the potential of crosslinked CNCs with tunable physicochemical properties for use as advanced building blocks to produce 2D and 3D structures for their related functions.

Recovery from chronic periodontal disease is associated with lower risk for incident diabetes.

AIM: The presence of periodontal disease (PD) at a single time point has been suggested as a predictor of diabetes risk, but whether changes in PD status are associated with altered risk of diabetes is yet to be reported on a population scale. This study investigated whether recovery from or development of PD in a population is associated with an altered risk of diabetes occurrence. MATERIALS AND METHODS: Data of subjects who received health screening from 2002 to 2007 were obtained from the National Health Insurance Service-National Health Screening cohort database of Korea. Patients with a history of diabetes were excluded. Changes in PD status were determined from the first two health screenings. Study subjects were divided into four groups according to the changes in PD status: PD-free, PD-recovered, PD-developed, and PD-chronic. The outcome was the occurrence of diabetes. RESULTS: Overall, 111,611 subjects were included for analysis. During a median follow-up of 9.10 years, diabetes developed in 6102 subjects. The adjusted hazard ratios (HRs) for incident diabetes across various PD change groups (in reference to the PD-free group) were as follows: PD-chronic group = 1.096 (95% confidence interval [CI] 1.026-1.170, p = .006); PD-developed group = 1.073 (95% CI 0.993-1.159, p = .075); and PD-recovered group = 1.019 (95% CI 0.945-1.100, p = .622). The subjects who recovered from PD had a lower diabetes risk than those who had consistent PD (adjusted HR 0.930, 95% CI 0.865-1.000, p = .050), whereas those who developed PD had a higher risk of diabetes than those who remained PD-free. CONCLUSION: The longitudinal change in PD status is associated with incident diabetes risk. Future intervention studies are necessary to determine whether PD treatment can prevent incident diabetes.

Identifying the course of the greater palatine artery using intraoral ultrasonography: cohort study.

AIMS: The greater palatine artery (GPA) is one of the most important anatomical structure for free gingival grafts or connective-tissue grafts during soft tissue surgery for dental implants. Several studies have identified the approximate location of the GPA, but it is impossible to detect its exact location during surgery due to large variability between individuals. The authors, therefore, investigated the course of the GPA using intraoral ultrasonography to determine the feasibility of using real-time nonionizing ultrasonography for implant surgery. MATERIALS AND METHODS: This study included 40 healthy young participants. The courses of the GPA were identified using intraoral ultrasound probes from the first premolar to the second molar. The distance from the gingival margin to the GPA (GM-GPA) and the depth of the palatal gingiva from the GPA (PG-GPA) were measured by two independent examiners. Measurements were analyzed statistically, and interexaminer reliability was determined. RESULTS: The distance of the GM-GPA and the mean depth of the PG-GPA were 14.8 ± 1.6 mm and 4.10 ± 0.51 mm (mean ± SD), respectively. GM-GPA decreased when the GPA ran from the second molar to the first molar, and GM-GPA was significantly shorter in females (P < 0.05). PG-GPA increased when the GPA ran to the posterior teeth. Interexaminer measurement agreements were excellent, with intraclass correlation coefficient values of 0.983 and 0.918 for GM-GPA and PG-GPA, respectively. CONCLUSIONS: Using an intraoral ultrasound probe, real-time GPA tracking is possible, which is expected to help reduce the possibility of bleeding during surgery.

Process Development for the Detoxification of Fermentation Inhibitors from Acid Pretreated Microalgae Hydrolysate.

The aim of this study was to remove 5-hydroxymethyl furfural (5-HMF) and furfural, known as fermentation inhibitors, in acid pretreated hydrolysates (APH) obtained from Scenedesmus obliquus using activated carbon. Microwave-assisted pretreatment was used to produce APH containing glucose, xylose, and fermentation inhibitors (5-HMF, furfural). The response surface methodology was applied to optimize key detoxification variables such as temperature (16.5-58.5 °C), time (0.5-5.5 h), and solid-liquid (S-L) ratio of activated carbon (0.6-7.4 w/v%). Three variables showed significant effects on the removal of fermentation inhibitors. The optimum detoxification conditions with the maximum removal of fermentation inhibitors and the minimum loss of sugars (glucose and xylose) were as follows: temperature of 36.6 °C, extraction time of 3.86 h, and S-L ratio of 3.3 w/v%. Under these conditions, removal of 5-HMF, furfural, and sugars were 71.6, 83.1, and 2.44%, respectively, which agreed closely with the predicted values. When the APH and detoxified APH were used for ethanol fermentation by S. cerevisiae, the ethanol produced was 38.5% and 84.5% of the theoretical yields, respectively, which confirmed that detoxification using activated carbon was effective in removing fermentation inhibitors and increasing fermentation yield without significant removal of fermentable sugars.

Mucormycosis originated total maxillary and cranial base osteonecrosis: a possible misdiagnosis to malignancy.

BACKGROUND: This is a case of mucormycosis originated osteonecrosis of the maxilla extended to the cranial base, initially suspected of malignancy. The patient was first suspected with osteolytic sarcomatous lesion but was later diagnosed with total maxillary necrosis and cranial base through biopsy-proven invasive mucormycosis. CASE PRESENTATION: A 71-year-old male was presented with unknown total maxillary osteonecrosis. CT and MRI results showed extensive osteolytic change with bone destruction of the cranial base, and PET-CT showed irregular hypermetabolic lesion in the area suspected of malignancy. The first biopsy results only presented tissue inflammation. Thus, several further endoscopic biopsy were performed through posterior pharyngeal wall. The patient was eventually diagnosed with mucormycosis and associated osteomyelitis with subsequent bone necrosis. With confirmed diagnosis, partial maxillectomy of the necrosed bone was performed under general anesthesia. At the 4 week follow-up, the patient showed full mucosal healing and no recurrence or aggravation of the maxilla and cranial base lesion was observed. CONCLUSIONS: Accurate diagnosis of atypical symptoms, timely diagnosis, and proper combination therapy of surgical intervention, antifungal agent, and antibiotic use for skull base osteomyelitis are all critical for proper treatment planning. In addition, biopsy and CT scans are essential in differentiating osteonecrosis from malignancy.

Oral health and changes in lipid profile: A nationwide cohort study.

AIM: We aimed to investigate the association of periodontitis and oral hygiene indicators with changes in blood lipid parameters in a nationwide, population-based cohort in a longitudinal setting. MATERIALS AND METHODS: We included nationwide health screening program participants who underwent oral health examination in 2009-2010 and follow-up examinations for lipid profile without exposure to lipid-lowering agents. RESULTS: During the 5.19-year median follow-up, 65,078 individuals (mean age at baseline examination: 55.41 ± 7.30 years) underwent 286,218 health examinations. The prevalence of periodontitis was 39%. In the multivariate mixed model analysis, periodontitis and tooth loss were associated with decreased high-density lipoprotein cholesterol levels (ß = -0.0066 mmol/L, standard error = 0.0026, p = .013) and increased triglyceride levels (ß=0.0307, mmol/L, standard error = 0.0049, p < .001), respectively. Compared with tooth brushing ≤1 time/day, tooth brushing ≥3 times/day was associated with increased high-density lipoprotein cholesterol levels (ß = 0.0176 mmol/L, standard error = 0.0052, p = .006) and decreased triglyceride levels (ß = -0.0285 mmol/L, standard error = 0.0090, p = .001). CONCLUSIONS: Periodontitis and tooth loss may be attenuating factors for blood high-density lipoprotein cholesterol and triglyceride levels, respectively. Frequent tooth brushing may improve dyslipidaemia, particularly blood high-density lipoprotein cholesterol and triglyceride levels. Oral hygiene improvement may reduce the risk of dyslipidaemia.

Oral health and gastrointestinal cancer: A nationwide cohort study.

AIMS: Poor oral hygiene is closely associated with bacteraemia and systemic inflammation, which are known mediators of cancer development. We investigated the relationship between oral hygiene indicators and the risk of gastrointestinal cancer in a nationwide population-based cohort. MATERIALS AND METHODS: This study was conducted on data from 150,774 subjects from the Korean National Health Screening Cohort. The occurrence of gastrointestinal cancer was analysed according to the presence of periodontal disease and oral hygiene indicators: frequency of toothbrushing, dental visits for any reason, professional dental cleanings and number of missing teeth. Gastrointestinal cancer was defined using International Statistical Classification of Diseases-10 codes C15-C26. RESULTS: During a median 11.6 years of follow-up, the estimated 10-year event rate for gastrointestinal cancer was 6.76%. In a multivariable analysis, after adjusting for age, sex, income level, regular exercise, alcohol consumption, smoking status, body mass index, history of comorbidities, systolic blood pressure and laboratory findings, frequent toothbrushing (≥3/day) was significantly associated with a reduced risk for gastrointestinal cancer (hazard ratio: 0.91, 95% confidence interval (0.86-0.96), p < .001, p for trend < .001). CONCLUSIONS: Good oral hygiene behaviour, especially frequent toothbrushing, could be associated with a lower risk of gastrointestinal cancer.

Soft tissue expander for vertically atrophied alveolar ridges: Prospective, multicenter, randomized controlled trial.

OBJECTIVES: Conventional guided bone regeneration (GBR) limits the amount of bone graft due to limited soft tissue expansion. We hypothesize that the use of tissue expander will successfully augment soft tissue prior to bone graft, allowing for sufficient amount of grafting which will lead to a more stable and effective vertical bone graft. The authors aimed to evaluate effectiveness of the novel self-inflating tissue expander for vertical augmentation in terms of soft tissue expansion, clinical outcomes, and related complications. MATERIAL AND METHODS: A prospective, multicenter, randomized controlled trial was performed on patients requiring vertical augmentation. For experimental group patients, the tissue expander was subperiosteally implanted and followed by a tunneling bone graft without full flap reflection. Control patients underwent conventional vertical GBR. Primary objectives were to evaluate the dimensional changes of soft tissue and radiographic vertical bone gain and retention. As a secondary outcome, clinical complications and thickness changes of expanded overlying tissue were assessed and analyzed. RESULTS: Twenty-three patients in each group were included. During a 4-week expansion, two of the experimental group showed over-expansion and one showed mucosal perforation associated with previous severe scars. The other patients showed uneventful expansion and mean tissue augmentation was 6.88 ± 1.64 mm vertically. Ultrasonographic measurements of overlying gingiva revealed no thinning after tissue expansion (p > .05). Significantly higher vertical bone gain was shown in the experimental group (5.12 ± 1.25 mm) compared with that in the control patients (4.22 ± 1.15 mm; p < .05). After a 6-month retention period, the mean vertical bone measurement of the controls had decreased to 1.90 mm (55.0% reduction), which was a significantly greater decrease than that in the experimental group (mean 3.55 mm, 30.7% reduction; p < .05). CONCLUSION: Our results demonstrated the effectiveness of tissue expanders followed by tunneling bone graft for vertical augmentation; however, studies comparing the two techniques without tissue expanders are needed to elucidate the net effect of tissue expansion.

Decompression of Large Cyst Invading the Mandibular Canal Leading to Reduced Cyst Volume and Increased Mandibular Canal Length.

PURPOSE: The mandibular canal is damaged by the growth of cysts, and remodeling of the mandibular canal is observed as the size of the cyst decreases after decompression procedures. This study aimed to estimate changes in cyst volume and mandibular canal length using cone-beam computed tomography (CBCT) before and after decompression surgery. MATERIALS AND METHODS: A retrospective cohort study was conducted in patients with a diagnosis of mandibular cyst invading the mandibular canal between 2012 and 2018. All patients underwent CBCT at the initial visit and after decompression. The predictor variable was the period before decompression and before enucleation surgery. The outcome variables were changes in cyst volume and mandibular canal length, which were evaluated 3-dimensionally. The initial volume of the cyst, initial length of the mandibular canal, and patient's age were set as variables of interest that affected the outcome. RESULTS: Decompression was performed in 20 patients (18 male and 2 female patients), and the mean decompression duration was 8.81 ± 2.94 months. The average volume reduction rate after decompression was 60.23%, with an average volume reduction speed of 0.72 mL/month. The average length increase rate after decompression was 50.88%, and the average speed of length increase was 2.68 mm/month. The initial volume of the cyst and initial length of the mandibular canal were the important variables affecting the results. Complete separation of the mandibular canal from the cyst was observed in 11 cases, and incomplete separation was found in 9. CONCLUSIONS: Separation from the cyst and regeneration of the mandibular canal using decompression were observed using 3-dimensional CBCT analysis. The results of this study suggest that decompression is effective in separating and preserving important anatomic structures invaded by the cyst.

Randomized controlled trial on the effectiveness of absorbable collagen sponge after extraction of impacted mandibular third molar: split-mouth design.

BACKGROUND: The purpose of this study was to compare the effectiveness of absorbable collagen sponge insertion in tooth extraction sites for socket healing of the impacted mandibular third molar. METHODS: Thirty-six patients with bilateral mandibular impacted third molars based on Pell-Gregory and Winter classification were included in this study. This study was a randomized clinical trial utilizing a split-mouth design with one side assigned as collagen sponge insertion and the other side assigned as the control. Post-operative clinical complications, periodontal integrities, and radiographic outcomes were assessed at 1, 2, and 14-weeks post operatively. RESULTS: Five patients were excluded during the follow-up period due to loss of follow-up. The study was conducted on 31 patients in total. The mean VAS score of collagen sponge insertion side at 1 week post operation was 1.42 ± 1.26, which was significantly lower than the control side (P < 0.05). The mean probing depth of collagen sponge insertion side at 2-week post operation was 5.55 ± 2.28 mm, which was significantly lower than the control side (7.13 ± 1.86; P < 0.05). Other various measurements including radiographic outcomes showed no significant group differences. CONCLUSIONS: Placement of collagen sponge after extraction of mandibular impacted third molar reduced early stage post-operative complications and enhanced initial healing of soft tissues and periodontal defects. TRIAL REGISTRATION: This study was retrospectively registered at the WHO ICTRP platform and Clinical Research Information Service, KCT0003363. Registered 21 Sep 2018.

Effect of PTH and corticotomy on implant movement under mechanical force.

BACKGROUND: Osseointegrated implants are considered as clinically non-movable. Parathyroid hormone (PTH) is known to play a significant role in the regulation of bone remodeling and in intermittent, low doses, result in osteoanabolic effects. This study aimed to investigate the effects of PTH and corticotomy, both under traction force, on osseointegrated implants. METHODS: Four implants-two in each hemimandible-were placed in each of the three study mongrels. Each mongrels were designated as control, normal dose PTH (PTH-1), and high dose PTH (PTH-2) groups, with each groups further subdivided into non-surgery implant and surgery implant. After osseointegration, mechanical force with NiTi closed coil springs (500 g) was applied around each implants. Corticotomy was performed around one of four implants in each mongrels. Parathyroid hormone was administered locally on a weekly basis for 20 weeks. Clinical movement of the implants were evaluated with the superimposed 3D- scanned data, bone- microarchitectural and histologic examinations. RESULTS: Superimposition analysis showed continuous movement of the non-surgery implant of PTH-1 group. Movement was further justified with lowest bone implant contact (adjusted BIC; 44.77%) in histomorphometric analysis. Upregulation of bone remodeling around the implant was observed in the normal dose PTH group. In the surgery implants, the remarkably higher adjusted BIC compared to the non-surgery implants indicated increased bone formation around the implant surface. CONCLUSION: The results indicate that the catabolic and anabolic balance of osseointegrated implants in terms of bone remodeling can be shifted via various interventions including pharmacological, surgical and mechanical force. CLINICAL RELEVANCE: Upregulated bone remodeling by PTH and corticotomy under continuous mechanical force showed the possible implications for the movement of osseointegrated dental implant.

Automated cephalometric landmark detection with confidence regions using Bayesian convolutional neural networks.

BACKGROUND: Despite the integral role of cephalometric analysis in orthodontics, there have been limitations regarding the reliability, accuracy, etc. of cephalometric landmarks tracing. Attempts on developing automatic plotting systems have continuously been made but they are insufficient for clinical applications due to low reliability of specific landmarks. In this study, we aimed to develop a novel framework for locating cephalometric landmarks with confidence regions using Bayesian Convolutional Neural Networks (BCNN). METHODS: We have trained our model with the dataset from the ISBI 2015 grand challenge in dental X-ray image analysis. The overall algorithm consisted of a region of interest (ROI) extraction of landmarks and landmarks estimation considering uncertainty. Prediction data produced from the Bayesian model has been dealt with post-processing methods with respect to pixel probabilities and uncertainties. RESULTS: Our framework showed a mean landmark error (LE) of 1.53 ± 1.74 mm and achieved a successful detection rate (SDR) of 82.11, 92.28 and 95.95%, respectively, in the 2, 3, and 4 mm range. Especially, the most erroneous point in preceding studies, Gonion, reduced nearly halves of its error compared to the others. Additionally, our results demonstrated significantly higher performance in identifying anatomical abnormalities. By providing confidence regions (95%) that consider uncertainty, our framework can provide clinical convenience and contribute to making better decisions. CONCLUSION: Our framework provides cephalometric landmarks and their confidence regions, which could be used as a computer-aided diagnosis tool and education.

Pre-application of dentin bonding agent prevents discoloration caused by mineral trioxide aggregate.

BACKGROUND: To evaluate tooth discoloration by newly developed calcium silicate-based materials, and to examine the pre-application of dentin bonding agent (DBA) for preventing discoloration caused by mineral trioxide aggregate (MTA). METHODS: The roots of 50 premolars were randomly divided into five groups (n = 10) and cavities were prepared from resected root surfaces. MTA was placed in the cavities of teeth belonging to the ProRoot MTA (MTA) and RetroMTA (RMTA) groups. For teeth belonging to the ProRoot + DBA (MTA-B) and RetroMTA + DBA (RMTA-B) groups, DBA was first applied to the cavities prior to the addition of MTA. Teeth in the control group were restored with composite resin only (i.e., without MTA). After 12 weeks, MTA was removed from the MTA and RMTA groups and bleaching agents were applied for 3 additional weeks. Color assessments were recorded at baseline, and 1, 4, and 12 weeks, as well as after bleaching. A one-way ANOVA was performed to assess the differences between the two types of MTAs and color changes following DBA pre-application in each MTA group. A p-value of < 0.05 was considered indicative of statistical significance. RESULTS: Following 12 weeks of MTA treatment, there was a significant difference between the discoloration in the MTA and RMTA groups (p < 0.05). However, no significant difference was observed between the RMTA and RMTA-B groups (p > 0.05). Following bleaching, the color changes (ΔE values) of the MTA group were not significantly different from those of the MTA-B group (p > 0.05). The difference of ΔE between the RMTA group after internal bleaching and the RMTA-B group was also not significant (p > 0.05). CONCLUSIONS: RetroMTA caused significantly less discoloration than ProRoot MTA. Pre-application of DBA reduced discoloration caused by ProRoot MTA. MTA discoloration was improved equally well between DBA pre-application and post-bleaching.

Orthognathic surgery Deteriorates the osseointegration of dental implants: A propensity-matched multicentre cohort study.

This study aimed to investigate the possible influence of the regional acceleratory phenomenon (RAP) on dental implant osseointegration. Orthognathic surgery was set as an intervention for RAP, and a multicentre cohort study of two groups was undertaken. Group O included patients with single implant placement at least 4 months after orthognathic surgery and functional loading for more than 1 year, while controls (Group C) were without any major surgery. Clinical and radiographic assessments of implants, including changes in marginal bone levels, were analysed at baseline, 6- and 12-month follow-up. Bivariate analysis of two groups with propensity score matching was performed. After propensity score matching, all 10 confounding variables had acceptable standardised difference scores (<20%), indicating that the matching procedure had efficiently balanced the two groups. Following the propensity score adjustment, the marginal bone loss was significantly higher in Group O than the control at 6 months (1.66 ± 1.05 mm vs 0.59 ± 0.64 mm, P < 0.001) and 12 months (2.30 ± 1.27 mm vs 0.82 ± 0.78 mm, P < 0.001). Compared to Group C, subjects in Group O had a higher incidence of peri-implant mucositis and implantitis (11.8% vs 1.5%, P = 0.033). Impaired osseointegration of dental implants was associated with orthognathic surgery. Special considerations for peri-implant soft and hard tissue stability should be addressed to obtain ideal treatment results and prognosis for patients who have had prior orthognathic surgery.