Mandibular Teeth Research Articles

NKUT: Dataset and Benchmark for Pediatric Mandibular Wisdom Teeth Segmentation.

Germectomy is a common surgery in pediatric dentistry to prevent the potential dangers caused by impacted mandibular wisdom teeth. Segmentation of mandibular wisdom teeth is a crucial step in surgery planning. However, manually segmenting teeth and bones from 3D volumes is time-consuming and may cause delays in treatment. Deep learning based medical image segmentation methods have demonstrated the potential to reduce the burden of manual annotations, but they still require a lot of well-annotated data for training. In this paper, we initially curated a Cone Beam Computed Tomography (CBCT) dataset, NKUT, for the segmentation of pediatric mandibular wisdom teeth. This marks the first publicly available dataset in this domain. Second, we propose a semantic separation scale-specific feature fusion network named WTNet, which introduces two branches to address the teeth and bones segmentation tasks. In WTNet, We design a Input Enhancement (IE) block and a Teeth-Bones Feature Separation (TBFS) block to solve the feature confusions and semantic-blur problems in our task. Experimental results suggest that WTNet performs better on NKUT compared to previous state-of-the-art segmentation methods (such as TransUnet), with a maximum DSC lead of nearly 16%.

A Cone-Beam Computed Tomography-Based Evaluation of Root Dilaceration in Permanent Premolars: A Retrospective Study.

As a developmental disorder characterized by an abnormal bend and angle in the longitudinal axis of the tooth root, dilaceration can cause complications in routine dental procedures such as endodontics, orthodontics, and surgical treatments. The purpose of this study was to investigate the prevalence of dilaceration in maxillary and mandibular premolar teeth in a population of Shiraz city based on cone-beam computed tomography (CBCT). This is a retrospective cross-sectional study on 927 premolar teeth and 132 CBCT radiographs of patients obtained from four private radiology clinics in Shiraz (Iran). In this study, the presence, location, direction, and severity of dilaceration in premolar roots as well as its relationship with gender were investigated. Chi-square and Fisher tests were used to analyze the data. The results showed that 17% of the studied 927 teeth had dilaceration. The prevalence of dilaceration was significantly higher in women than in men (20.3% vs. 13.6%, p= 0.005). The dilaceration rates were significantly higher in the mandibular first and second premolar teeth (31.6% and 26%, p= 0.002) than in the other teeth. In addition, the highest prevalence was in the distal direction with mild severity in the apical third of the root (p< 0.001). According to the results of this study, the prevalence of dilaceration was relatively high in mandibular premolar teeth especially in women.

Effect of ultrasonic and Er,Cr:YSGG laser-activated irrigation protocol on dual-species root canal biofilm removal: An in vitro study.

The aim of the study was to investigate the disinfecting efficacy of a standardized irrigating solution activated by ultrasonics or laser irradiation on mature dual-species biofilms at different root levels in vitro. Conventional access cavity preparations were done on 160 single-rooted mandibular premolar teeth with single canals. Freshly extracted oral microbial strains of Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis, and Candida albicans after biochemical confirmation were used to generate two discrete dual-species microbial inoculums. The sterilized tooth samples were randomly segregated into two groups (n = 80) and inoculated with a mixed inoculum of S. aureus + E. faecalis strains (Group 1) and S. mutans + C. albicans strains (Group 2), respectively. Following the 21-day incubation period under aerobic conditions, the infected specimens in each group were divided into four subgroups (n = 20) and subjected to experimental treatment protocols. This included a positive control (no treatment of biofilms), syringe irrigation alone with TruNatomy needle, passive ultrasonically activated irrigation with 20# Irrisafe tip, and laser agitation of irrigant with Er,Cr:YSGG laser using RFT 2 laser tip. Root canals of experimental specimens (except the control samples) are instrumented with TruNatomy rotary file system using 1:1 mixture of 3% NaOCl and 18% etidronic acid as irrigants. The quantitative assessment of reduction in viable biofilm microbes after treatment was done using colony-forming unit counts and confocal laser scanning microscopy image analysis. The obtained data were analyzed statistically with a significant level set at 0.05. Laser-assisted irrigation has shown a considerably higher mean percentage reduction of microbes compared to ultrasonic agitation and the syringe irrigation showed the least microbial reduction (P = 0.001). No significant difference was noted between the three root regions of ultrasonic and laser groups (P > 0.05), whereas in the syringe groups, apical portions showed higher microbial counts compared to cervical and mid-root regions (P = 0.001). Erbium laser-assisted irrigation has performed superior to ultrasonic agitation against both the experimental dual-species biofilms, while the syringe irrigation showed the least microbial reduction specifically at apical root portions.

Changes in Osteocalcin Levels During Orthodontic Tooth Movement in Periodontally Affected Mandibular Anterior Teeth

Changes in Osteocalcin Levels During Orthodontic Tooth Movement in Periodontally Affected Mandibular Anterior Teeth

Effect of apical foraminal enlargement on postoperative pain and inflammatory markers in asymtomatic single-rooted mandibular teeth with apical periodontitis - An in vivo randomized controlled trial.

This study aims to assess the effect of apical foraminal enlargement on inflammatory markers and pain in patients with asymptomatic single-rooted mandibular teeth with apical periodontitis. The study included 60 patients based on inclusion and exclusion criteria. Before beginning root canal treatment (RCT), a blood sample was obtained from the antecubital fossa to evaluate the inflammatory markers, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR). Access opening was done and initial irrigation was done. Working length (WL) was determined with an electronic apex locator and verified with a radiograph. In the control group, the determined WL was maintained, while in the experimental group, the WL was set till the apical foramen. Biomechanical preparation was done in both groups till F2 or F3 based on the initial apical file, followed by final irrigation and obturation based on the master apical file size. Patients were given a Visual Analog Scale to record pain sensations at 24, 48, and 72 h postoperative. After 72 h, patients were recalled for follow-up appointments, and blood was taken from the antecubital fossa again to evaluate inflammatory markers. The resultant findings for the reduction in inflammatory markers before and after RCT with or without foraminal enlargement were statistically analyzed using the Student's t-test. The pain was statistically examined with one-way "analysis of variance" and Tukey's post hoc test for inter-group comparison of pain. The level of significance was set at P < 0.05. The statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) Version 23 for Windows (SPSS Inc., Chicago, IL, USA). As pain in the control groups is zero before and after RCT, statistical analysis is not required as the overall pain score is zero. The P values of the CRP and ESR of the control group were 0.02 and 0.03, respectively, which indicates it is significant whereas the P values of the ESR and CRP of the experimental group were 0.0002 and 0.0008 which indicates it is highly significant. Results indicate that the experimental group is more effective compared to the control group in reducing inflammatory markers. Pain in the control group after RCT was zero at the end of 24, 48, and 72 h. In the experimental group, where RCT was done with apical foraminal enlargement, mild pain was present at the end of 24 h which gradually decreased at the end of 48 h and no pain was reported at the end of 72 h. Reduction in inflammatory markers was more effective in RCT with apical enlargement than without apical enlargement. RCT with apical enlargement caused mild pain in the patients immediately after treatment which gradually decreased over time.

Efficacy of Oral Magnesium on Bone Regeneration and Implant Stability in Immediate Dental Implants: A Randomized Controlled Trial.

The successful osseointegration around immediate implants requires high quality and quantity of osteogenesis around them. The role of magnesium as a boneenhancing mineral, and as an adjunctive analgesic has been well documented in orthopedic literature. However, there is a paucity of literature in its role in successful osseointegration around immediate implants. This randomized controlled trial sought to assess the promising impact of magnesium on osseointegration by examining various aspects of implant stability, correlating them with serum bone markers, and establishing a foundation for future research on its potential as a potent analgesic. Immediate implant placement was done after the extraction of the indicated mandibular molar tooth, and all the patients were segregated into 2 groups (Placebo- Lactose, and Magnesium citrate). Bone regenerate in the peri-implant area was assessed radiographically immediate post-operatively, on the 6th week and 12 weeks. Implant stability was measured immediate post-operatively, at the 4th week and 12th week. Serum parameters were procured pre-operatively and post-operatively for serum calcium, serum alkaline phosphatase (ALP), and serum parathyroid hormone at the 8th week, and serum vitamin D3 levels preoperatively. 54 immediate implants placed showed the demographics and baseline serum, clinical, and radiographic parameters were comparable in both groups. Analysis of Implant Stability Quotient at 12th week showed statistically significant difference in intervention group both on intergroup and intragroup analysis. Radiodensity measurement showed a statistically significant difference in both intragroup and intergroup analysis in the intervention group at the 6th and 12th week. In bone gap analysis, the difference in mean change in the horizontal bone gap (HG) at 6 weeks was non-significant while the difference in HG at the 12th week was significant in the intervention group. On intragroup analysis, mean change HG at 6 weeks and 12 weeks both were significant only in intervention group. Intergroup analysis of vertical bone gap (VG) 12 and VG 12-0 (mean difference in the vertical bone gap from 12th week-day 0) showed a statistically significant difference in the intervention group. On intragroup analysis, VG 12 was significantly better in the intervention group. On serum analysis, ALP post-operatively was found to be significantly raised (P=0.013) in intervention group. Numerical rating Scale (NRS) analysis showed a significant decrease in post-op day 5 and 7, (P=0.017) and (P=0.002) respectively. The oral magnesium citrate supplementation after immediate implant placement helps in enhancing the stability of the immediate implants, along with improved radiodensity around them which was found to be statistically significant. It also helps in reducing the horizontal, and vertical gap around the implant and has significant analgesic potential.

Mesiodistal and buccolingual crown widths of mandibular molar teeth in adult Sudanese and their clinical correlations

Mesiodistal and buccolingual crown widths of mandibular molar teeth in adult Sudanese and their clinical correlations

Comparative effects of 17% ethylenediaminetetraacetic acid and 9% etidronic acid applied with different irrigant activation techniques on the release of growth factors from dentin: in vitro study.

Growth factors embedded in the extracellular matrix of the dentin play an important role in the migration, proliferation, and differentiation of dental pulp stem cells in regenerative endodontics. In regenerative endodontic treatments, the type of irrigation solution used is crucial for the release of growth factors (GFs) from the dentin matrix. This study evaluated the effectiveness of different irrigant activation techniques (IAT) using two different chelating agents, 17% ethylenediaminetetraacetic acid (EDTA) and 9% etidronic acid (HEDP), in terms of their GF release. Seventy-two mandibular premolar teeth were prepared to simulate an open apex. The root fragments were irrigated with 20ml of 1.5% sodium hypochlorite and 20ml of saline solution. Eight root fragments were randomly separated for the control group, and the remaining 64 fragments were randomly separated into eight groups based on two different chelating agents (17% EDTA and 9% HEDP) and four different IAT ((conventional needle irrigation (CNI), passive ultrasonic irrigation (PUI), sonic activation with EDDY, and XP-endo Finisher (XPF)). TGF-β1, VEGF-A, BMP-7 and IGF-1 release levels were determined using an ELISA, and statistical analysis was performed using the Kolmogorov-Smirnov test, ANOVA, and the Tukey test (p < .05). Compared to the control group, the experimental groups showed significantly higher GF release when using EDTA or HEDP. Among the activation groups, the EDDY group triggered the highest GF release, and the CNI group triggered the lowest. IAT with EDTA and HEDP can increase GF release, with EDDY being the most effective IAT method. Using chelating agents with IAT may be beneficial in regenerative endodontic treatments.

Evaluating stress and displacement in the craniomandibular complex using Twin Block appliances at varied angles: A finite element study

ObjectivesThe objective of this investigation was to assess the stress and displacement pattern of the craniomandibular complex by employing finite element methodology to simulate diverse angulations of inclined planes that are incorporated in the Twin Block appliance. MethodsA 3D finite element representation was established by use of Cone Beam Computed Tomography (CBCT) scans. This comprehensive structure included craniofacial skeletal components, the articular disc, a posterior disc elastic layer, dental elements, periodontal ligaments, and a Twin Block appliance. This investigation is the first to incorporated inclined planes featuring three distinct angulations (45, 60, and 70°) as the study models. Mechanical impacts were evaluated within the glenoid fossa, tooth, condylar, and articular disc regions. ResultsIn all simulations, the stress generated by the Twin Block appliance was distributed across teeth and periodontal ligament, facilitating the anterior movement of mandibular teeth and the posterior displacement of maxillary teeth. Within the temporomandibular joint region, compressive forces on the superior and posterior facets of the condyle diminished, coinciding with the stress configuration that fosters condylar and mandibular growth. Stress dispersion homogenized in the condylar anterior facet and articular disc, with considerable tensile stress in the glenoid fossa's posterior aspect conforming to stress distribution that promote fossa reconfiguration. The 70° inclined plane exerts the highest force on the tissues. The condyle's maximum and minimum principal stresses are 0.36 MPa and −0.15 MPa, respectively, while those of the glenoid fossa are 0.54 MPa and −0.23 MPa. ConclusionThree angled appliances serve the purpose of advancing the mandible. A 45° inclined plane relative to the occlusal plane exerts balanced anteroposterior and vertical forces on the mandibular arch. Steeper angles yield greater horizontal forces, which may enhance forward growth and efficient repositioning.

Patterns and Determinants of Primary Tooth Extraction in Children: A Study in an Indian Tertiary Care Dental Setting.

Preservation of primary teeth is essential for optimal oral health in children; however, there is limited research on primary tooth extraction patterns in India. This study aimed to investigate the reasons for and patterns of primary tooth extraction in children in an Indian tertiary care dental setting. This retrospective cross-sectional study analyzed dental records of children aged up to 14 years who underwent tooth extraction under local anesthesia from January to December 2023. Demographic data, reasons for extraction, and tooth types extracted were collected and analyzed using descriptive statistics and the Chi-square test. Among the 261 subjects studied, there were 132 males and 129 females. Dental caries was the leading cause of extraction (42.6%), followed by mobility (20.8%) and over-retention (17.3%). Maxillary teeth were extracted more frequently than mandibular teeth, with central incisors being the most commonly extracted. This study highlights the prevalence of dental caries as the primary reason for primary tooth extraction in Indian children. Gender-specific differences were observed in extraction reasons, and maxillary teeth were more frequently extracted than mandibular teeth. These findings emphasize the importance of targeted preventive strategies to address dental caries and promote optimal oral health in children in India.

Clinical and histopathological study of 279 dentigerous cysts in 192 dogs (2012–2022)

Unerupted teeth in dogs are fairly common and may develop an odontogenic cyst that causes destruction of the surrounding bone and affect adjacent teeth. We analyzed histological reports of cysts associated with unerupted teeth in a large population of dogs. Medical records and histopathological results of cysts associated with unerupted teeth were evaluated from all dogs treated at a private referral veterinary dental clinic over a 10-year period (2012–2022). A total of 192 dogs with 279 cysts associated with one or more unerupted teeth were included in the study. Brachycephalic breeds were overrepresented. The most affected were Tibetan Spaniels with 58 dogs (30%) and Boxers with 48 dogs (25%). The most common affected tooth was the mandibular first premolar tooth with 238 (84%) cysts. Of the total of 279 cysts, 208 (75%) were histopathologically examined. None of the cysts examined contained malignant changes. Based on these 208 cysts, the probability of finding a cyst with malignant changes in a population of dogs is 0–1.4% (confidence interval 95%).

Effects of Occlusal Contact on Maxillary Alveolar Bone Morphology in Patients with and without Anterior Open Bite: A Cross-Sectional Study.

Background/Objectives: Anterior open bite (AOB) is characterized by the absence of occlusal contact between the maxillary and mandibular anterior teeth, while the posterior teeth are in contact when occluded. Here, we aimed to clarify the difference in maxillary alveolar bone morphology in adult patients with and without AOB. Methods: This cross-sectional study was conducted on 50 adults aged 18-39 years: 25 patients without AOB (control group; 13 males and 12 females; age: mean ± standard deviation [SD], 22.2 ± 4.5 years) and 25 patients with AOB (9 males and 16 females; age: 24.2 ± 6.4 years). Using cone-beam computed tomography images, the height of the maxillary alveolar bone crest in the anterior and posterior teeth and thickness of the alveolar cortical bone on the labial and palatal sides were measured and compared between the two groups. An independent t-test and Pearson's correlation analysis were used to examine statistical significance (p < 0.05). Results: The AOB group showed a significantly longer (p = 0.016) posterior alveolar crest and thinner cortical bone on the buccal (p < 0.001) and lingual (p = 0.009) sides of the anterior region and the buccal (p = 0.006) sides of the posterior region than the control group did. Moreover, a significant negative correlation (p = 0.046; r = -0.403) was observed between bite force and cortical bone thickness on the buccal side of the posterior region in the AOB group. Conclusions: It is suggested that the absence of occlusal contact in the anterior area influences the alveolar bone morphology of the maxilla.

A Combined Ventral Extraoral and Intraoral Approach for Mandibulectomy in 9 Cats: A Case Series.

This retrospective case series describes a combined ventral extraoral and intraoral approach for mandibulectomy in cats and highlights the importance of prompt management of the postoperative iatrogenic malocclusion through dental extraction, crown height reduction with vital pulp therapy or root canal therapy of the contralateral mandibular canine tooth. Nine cats were reviewed for signalment, history and physical examination, diagnostic workup, tumor type, mandibulectomy extension, lymph node removal as well as both intraoperative and postoperative complications. The performed surgical procedure was a combination of an extraoral approach ventrally to the mandible and an intraoral approach to remove the whole or a part of the mandible. Lymphadenectomy was achieved using the same surgical access. None of the cats had intraoperative complications. Postoperative complications were limited to regional swelling and drooling lasting a week. Seven cats were able to eat immediately after the surgery. Of the other 2 cats, 1 regained the ability to eat within a month and 1 only ate from the owner's hands. The surgical approach for mandibulectomy described allowed better access and visualization of the caudal part of the mandible and direct access to regional lymph nodes. Moreover, if the expected postoperative malocclusion is managed during the same surgical procedure, there is a higher rate of postoperative eating ability compared to what is reported in the literature.

Characterizing the Root Canal Configuration of Mandibular Incisors in a Western Saudi Arabian Sub-population Using Cone Beam Computed Tomography.

Aim This study aimed to explore the morphology and complexity of mandibular anterior teeth in a Western Saudi Arabian sub-population using cone beam computed tomography (CBCT). Methodology CBCT scans from 818 patients were evaluated, and 3193 mandibular anterior teeth were analyzed for the number of roots, canal, canal configurations, separation level, bilateral symmetry, and gender associations. Results The results showed that all examined central and lateral incisors had a single root, and the majority exhibited a single canal. The prevalence of two canals in mandibular central and lateral incisors was 20.1% and 23.2%, respectively, resulting in an overall prevalence of 21.7% for two root canals in mandibular anterior teeth. The separation level of the two canals was predominantly located in the middle third of the root. Type I canal configuration was the most common, followed by type III. A high degree of bilateral symmetry in the number of canals and canal configurations was noted. Conclusion The findings contribute to the understanding of root canal anatomy in the Saudi population and provide valuable information for endodontic treatment planning.

Clinical Survival Rate and Laboratory Failure of Dental Veneers: A Narrative Literature Review.

There is a vast amount of published literature concerning dental veneers; however, the effects of tooth preparation, aging, veneer type, and resin cement type on the failure of dental veneers in laboratory versus clinical scenarios are not clear. The purpose of the present narrative review was to determine the principal factors associated with failures of dental veneers in laboratory tests and to understand how these factors translate into clinical successes/failures. Articles were identified and screened by the lead author in January 2024 using the keywords ''dental veneer", "complication", "survival rate", "failure", and "success rate" using PubMed/Medline, Scopus, Google Scholar, and Science Direct. The inclusion criteria included articles published between January 1999 and January 2024 on the topics of preparation of a tooth, aging processes of the resin cement and veneer, translucency, thickness, fabrication technique of the veneer; shade, and thickness of the resin cement. The exclusion criteria included articles that discussed marginal and internal fit, microhardness, water sorption, solubility, polishability, occlusal veneers, retention, surface treatments, and wear. The results of the present review indicated that dental veneers generally have a high survival rate (>90% for more than 10 years). The amount of preserved enamel layer plays a paramount role in the survival and success rates of veneers, and glass-ceramic veneers with minimal/no preparation showed the highest survival rates. Fracture was the primary failure mechanism associated with decreased survival rate, followed by debonding and color change. Fractures increased in the presence of parafunctional activities. Fewer endodontic complications were associated with veneer restorations. No difference was observed between the maxillary and mandibular teeth. Clinical significance: Fractures can be reduced by evaluation of occlusion immediately after cementation and through the use of high-strength veneer materials, resin cements with low moduli, and thin layers of highly polished veneers. Debonding failures can be reduced with minimal/no preparation, and immediate dentin sealing should be considered when dentin is exposed. Debonding can also be reduced by preventing contamination from blood, saliva, handpiece oil, or fluoride-containing polishing paste; through proper surface treatment (20 s of hydrofluoric acid etching for glass ceramic followed by silane for 60 s); and through use of light-cured polymerization for thin veneers. Long-term color stability may be maintained using resin cements with UDMA-based resin, glass ceramic materials, and light-cure polymerization with thin veneers.

Radiologic evaluation of associated symptoms and fractal analysis of unilateral dens invaginatus cases.

The aim of this study is to determine the age-based prevalence of dens invaginatus cases and to learn the radiologic findings. In addition, fractal analysis of the periapical regions of unilateral dens invaginatus cases and contralateral teeth was performed to determine the effect of possible microleakage on fractal dimension. A total of 136 patients (170 teeth) identified in panoramic radiographs taken for diagnostic purposes between January 2018 and December 2023 at our Department of Oral and Maxillofacial Radiology were included in the study. Data were analysed using IBM SPSS V23. The Chi-square test was used for comparing categorical variables between groups. The relationship between the FD values calculated around the apexes of the teeth with unilateral dens invaginatus and the contralateral teeth was analyzed by paired t test. A significance level of p < 0.050 was adopted. The mean age of the cases was calculated as 28.1 (8-63) years. 66 (48.5%) of the cases were female, and 70 (51.1%) were male. The lateral incisor was the most affected tooth among these cases. Bilateral cases were observed in 34 patients. Type 2 was detected in 93 patients, Type 1 in 35 patients, and Type 3 dens invagination in 8 patients. Dens invaginatus cases were observed in 134 maxillary and 2 mandibular teeth. Periapical lesions were seen in 22 of these cases. Dens invaginatus cases are a congenital anomaly encountered at any age. Early diagnosis is crucial to prevent the loss of pulp vitality due to these invaginations. It should be noted that these invaginations can affect both jaws. However, due to the prevalence of occurrence in the maxillary anterior teeth and asymptomatic nonvitality, particular attention should be paid to evaluating this region.

Biomechanical impact of different isthmus positions in mandibular first molar root canals: a finite element analysis.

This study used image-based finite element analysis (FEA) to assess the biomechanical changes in mandibular first molars resulting from alterations in the position of the root canal isthmus. A healthy mandibular first molar, characterized by two intact root canals and a cavity-free surface, was selected as the subject. A three-dimensional model for the molar was established using scanned images of the patient's mandibular teeth. Subsequently, four distinct finite element models were created, each representing varied root canal morphologies: non-isthmus (Group A), isthmus located at the upper 1/3 of the root (Group B), middle 1/3 of the root (Group C), and lower 1/3 of the root (Group D). A static load of 200 N was applied along the tooth's longitudinal axis on the occlusal surface to simulate regular chewing forces. The biomechanical assessment was conducted regarding the mechanical stress profile within the root dentin. The equivalent stress (Von Mises stress) was used to assess the biomechanical features of mandibular teeth under mechanical loading. In Group A (without an isthmus), the maximum stress was 22.2MPa, while experimental groups with an isthmus exhibited higher stresses, reaching up to 29.4MPa. All maximum stresses were concentrated near the apical foramen. The presence of the isthmus modified the stress distribution in the dentin wall of the tooth canal. Notably, dentin stresses at specific locations demonstrated differences: at 8mm from the root tip, Group B: 13.6MPa vs. Group A: 11.4MPa; at 3mm from the root tip, Group C: 14.2MPa vs. Group A: 4.5MPa; at 1mm from the root tip, Group D: 25.1MPa vs. Group A: 10.3MPa. The maximum stress in the root canal dentin within the isthmus region was located either at the top or bottom of the isthmus. A root canal isthmus modifies the stress profile within the dentin. The maximum stress occurs near the apical foramen and significantly increases when the isthmus is located closer to the apical foramina.

Layer-by-layer self-assembly of PLL/CPP-ACP multilayer on SLA titanium surface: Enhancing osseointegration and antibacterial activity in vitro and in vivo

Dental Implants are expected to possess both excellent osteointegration and antibacterial activity because poor osseointegration and infection are two major causes of titanium implant failure. In this study, we constructed layer-by-layer self-assembly films consisting of anionic casein phosphopeptides-amorphous calcium phosphate (CPP-ACP) and cationic poly (L-lysine) (PLL) on sandblasted and acid etched (SLA) titanium surfaces and evaluated their osseointegration and antibacterial performance in vitro and in vivo. The surface properties were examined, including microstructure, elemental composition, wettability, and Ca2+ ion release. The impact the surfaces had on the adhesion, proliferation and differentiation abilities of MC3T3-E1 cells were investigated, as well as the material’s antibacterial performance after exposure to the oral microorganisms such as Porphyromonas gingivalis (P. g) and Actinobacillus actinomycetemcomitans (A. a). For the in vivo studies, SLA and Ti (PLL/CA-3.0)10 implants were inserted into the extraction socket immediately after extracting the rabbit mandibular anterior teeth with or without exposure to mixed bacteria solution (P. g & A. a). Three rabbits in each group were sacrificed to collect samples at 2, 4, and 6 weeks of post-implantation, respectively. Radiographic and histomorphometry examinations were performed to evaluate the implant osseointegration. The modified titanium surfaces were successfully prepared and appeared as a compact nano-structure with high hydrophilicity. In particular, the Ti (PLL/CA-3.0)10 surface was able to continuously release Ca2+ ions. From the in vitro and in vivo studies, the modified titanium surfaces expressed enhanced osteogenic and antibacterial properties. Hence, the PLL/CPP-ACP multilayer coating on titanium surfaces was constructed via a layer-by-layer self-assembly technology, possibly improving the biofunctionalization of Ti-based dental implants.

Food impaction on three-dimensional printed models with periodontal ligament simulation.

This study aims to evaluate food impaction on three-dimensional (3D) printed models with periodontal ligament simulation. Based on a commercial typodont pair, 3D maxillary and mandibular models were created with no teeth and with tooth sockets that were 1 mm wider than the original ones from 24 to 27 or 34 to 37 for periodontal ligament simulation with vinyl polysiloxane impression material. In total, 35 pairs of 7 combinations, including maxillary/mandibular typodonts in occlusion with maxillary/mandibular 3D models with/without a distal gap of canines on 3D models (tooth 23 or 33) were mounted on hinge articulators and divided into seven groups (n = 5). Each sample experienced the same manual chewing simulation on a customized device. The proximal surfaces were photographed to measure the percentage of food impaction area using ImageJ software. Group with fixed maxillary and mandibular teeth showed more food impaction than other groups with significant differences in the average of maxilla and the average of all proximal areas. The flexibility of the periodontal ligament and the degree of freedom of the teeth in their sockets may contribute to the extent of food impaction in proximal spaces.

The effect of different irrigation activation methods on the penetration of the irrigation solution into the dentinal tubules in teeth with calcium hydroxide applied and oval-shaped canals: Confocal laser scanning microscope analysis.

This study aimed to evaluate the efficacy of different irrigation techniques including standard needle irrigation (SNI), passive ultrasonic irrigation (PUI), EndoActivator (EA), XP-Endo Finisher (XPF), photon-induced photoacoustic streaming (PIPS), and shock wave enhanced emission photo-acoustic streaming (SWEEPS) systems on the penetration of irrigation solutions into dentinal tubules in teeth with calcium hydroxide (CH) applied and oval-shaped canals by confocal laser scanning microscope (CLSM). Ninety mandibular incisor teeth with oval-shaped canals were included in this study. After the preparation of teeth using Resiproc Blue R25 (VDW, Munich, Germany) canals were filled with a paste based on CH. The teeth were stored in 100% humidity at a temperature of 37°C for 14 days. According to the irrigation activation systems, the teeth were divided into six groups (n = 15); SNI, PUI, EA, XPF, PIPS, and SWEEPS. In each group, 3 irrigation/activation cycles of 20 s of irrigation and 20 s of activation were performed with the relevant activation method. The root canals were filled with fluorescein sodium (Sigma, Alldrich Co., St. Louis, MO, USA) and activated with the relevant activation method for 30 s. Specimens were sectioned horizontally to 1 ± 0.1 mm at 2, 5, and 8 mm from the apex and then examined under the CLSM. Maximum penetration depth, maximum penetration area and penetration percentage were measured by using Image J software. Data were analyzed using a two-way analysis of variance (ANOVA) and posthoc Tukey tests (p = .05). No difference was found between the activation systems in terms of maximum penetration depth and maximum penetration area of irrigation solutions in the apical section (p > .05). The penetration percentage of irrigation solutions was higher in PUI and PIPS compared with EA and XPF at the apical section (p < .05). No difference was found between SNI, PUI, PIPS, and SWEEPS in terms of the penetration percentage of irrigation solutions in all sections (p > .05). The penetration percentage of irrigation solutions was higher in the middle and coronal sections compared to the apical section in EA and XPF (p < .05). Tubule penetration of irrigation solutions in SNI was similar between sections. The Tubule penetration area of irrigation solutions in PUI, EA, XPF, PIPS, and SWEEPS was lower in the apical section than in the middle and coronal sections. RESEARCH HIGHLIGHTS: The tubule penetration depth and area of the irrigation solutions were similar between the activation systems tested in the apical sections. The Tubule penetration area of irrigation solutions in middle and coronal sections was higher in PUI and PIPS than in SNI.