Maxillary Molars Research Articles

The role of uncoupling protein 2 in experimental periodontitis-associated renal injury in rats.

This study aims to explore changes in uncoupling protein 2 (UCP2) in experimental periodontitis-associated renal injury induced by ligation and investigate the effect of UCP2 on renal injury induced by periodontitis. Twelve Wistar male rats were randomly divided into two groups: control and periodontitis groups. A periodontal model was built by ligating the maxillary first molars area with 0.2 mm orthodontic ligature wire. After 8 weeks, the intraoral condition of the rats was observed and periodontal clinical indices such as gingival bleeding index (BI), periodontal probing depth (PD), and tooth mobility (TM) were detected. The maxillary bone was scanned by Micro CT to observe the alveolar bone resorption. The tissue mineral density (TMD), bone mineral density (BMD), bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular bone separation (Tb.Sp) were recorded, and the distance from the enamel bone boundary to the alveolar crest (CEJ-ABC) of the maxillary first molar was measured. The oxidative stress indexes such as malondialdehyde, glutathione (GSH), and superoxide dismutase (SOD) were detected using frozen rat kidney tissue. The gene expression of UCP2, nuclear factor erythroid 2-related factor 2 (Nrf2), and peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) was observed by quantitative real-time polymerase chain reaction (qRT-PCR) test. The gingival tissue of the rats was used for immunohistochemical staining to observe the expression of the UCP2 protein. The fixed rat kidney tissue was used for hematoxylin-eosin (HE), periodic acid-schiff (PAS), MitoSOX Red, JC-1, and immunohistochemical staining to observe the renal histopathology, the level of reactive oxygen species (ROS), the level of mitochondrial membrane potential, and the expression of UCP2, Nrf2, and PGC-1α protein. Rat serum was collected to detect renal function indices, namely, blood urea nitrogen (BUN), creatinine (Cre), and albumin (Alb). Compared with the control group, the periodontitis group showed red, swollen, and soft gingival tissue, with gingival probing bleeding, periodontal PD increased, tooth loosening, alveolar bone resorption, decreased TMD, BMD, BV/TV, and Tb.Th indices, and increased Tb.Sp index, CEJ-ABC, and gingival UCP2 protein expression. Compared with the control group, the levels of MDA and ROS in the kidney tissue of periodontitis rats and the gene and protein expression of UCP2 increased, and the levels of MMP, GSH, and SOD and the gene and protein expression of Nrf2 and PGC-1α decreased. Renal functional indices, namely, BUN, Cre, and Alb, were not significantly different between the two groups. UCP2 may play a role in renal injury induced by periodontitis through oxidative stress.

Osteogenic potency of dental stem cell-composite scaffolds in an animal cleft palate model

ObjectiveTo evaluate the osteogenic potency of stem cells isolated from human exfoliated deciduous teeth (SHED) in polycaprolactone with gelatin surface modification (PCL-GE) and poly (lactic-co-glycolic acid)-bioactive glass composite (PLGA-bioactive glass (BG)) scaffolds after implantation in a rat cleft model. MethodsCleft palate-like lesions were induced in Sprague-Dawley rats by extracting the right maxillary first molars and drilling the intact alveolar bone. Rats were then divided into five groups: Control, PCL-GE, PCL-GE-SHED, PLGA-BG, and PLGA-BG-SHED, and received corresponding composite scaffolds with/without SHED at the extraction site. Tissue samples were collected at 2, 3, and 6 months post-implantation (4 rats per group). Gross and histological analyses were conducted to assess osteoid or bone formation. Immunohistochemistry for osteocalcin and human mitochondria was performed to evaluate bone components and human stem cell viability in the tissue. ResultsBone tissue formation was observed in the PCL-GE and PLGA-BG groups compared to the control, where no bone formation occurred. PLGA-BG scaffolds demonstrated greater bone regeneration potential than PCL-GE over 2–6 months. Additionally, scaffolds with SHED accelerated bone formation compared to scaffolds alone. Osteocalcin expression was detected in all rats, and positive immunoreactivity for human mitochondria was observed in the regenerated bone tissue with PCL-GE-SHED and PLGA-BG-SHED. ConclusionPCL-GE and PLGA-BG composite scaffolds effectively repaired and regenerated bone tissue in rat cleft palate defects. Moreover, scaffolds supplemented with SHED exhibited enhanced osteogenic potency. Clinical significancePCL-GE and PLGA-BG scaffolds, augmented with SHED, emerge as promising biomaterial candidates for addressing cleft repair and advancing bone tissue engineering endeavors.

Macrophage Polarization during MRONJ Development in Mice

Macrophages are important regulators of bone remodeling, and M1 polarization is observed in the setting of medication-related osteonecrosis of the jaws (MRONJ). Here, we characterize the phenotype of macrophages during early stages of MRONJ development in zoledronate (ZA)–treated mice with periodontal disease and explore the role of rosiglitazone, a drug that has been reported to lower the M1/M2 macrophage ratio, in MRONJ burden. Mice received ZA, and experimental periodontal disease (EPD) was induced around their second left maxillary molar. The mice were euthanized 1, 2, or 4 wk later. Micro–computed tomography and histologic and immunohistochemical analyses were carried out. In a separate experiment, mice were treated with ZA in the absence or presence of rosiglitazone, EPD was induced for 5 wk, and the MRONJ burden was assessed. An M1 predilection was noted in ZA versus vehicle (Veh) mice at 1, 2, or 4 wk after ligature placement. M1 cells were found to be positive for MMP-13, and their presence coincided with disruption of the surrounding collagen network in ZA mice. Rosiglitazone caused a reversal in the M1/M2 polarization in Veh and ZA mice. Rosiglitazone did not cause significant radiographic changes 5 wk after EPD in Veh or ZA animals. Importantly, percentage osteonecrosis and bone exposure were decreased in the rosiglitazone-treated versus nontreated ZA sites 5 wk after EPD. Our data point to an important role of M1 macrophage polarization with an overexpression of MMP-13 in the early phases of MRONJ development and provide insight into the use of interventional approaches promoting an M2 phenotype as a preventative means to alleviate MRONJ burden.

The Impact of Minimum Invasive Access Cavity Design on the Quality of Instrumentation of Root Canals of Maxillary Molars Using Cone-Beam Computed Tomography: An in Vitro Study.

Aim Minimally invasive dentistry has been facilitated by advances in instruments and restorative materials. This study aims to compare the change in the shaping ability of the RECIPROC blue rotary system in both traditional and conservative access cavities, using cone beam computed tomography (CBCT). Material and methods Sixty root canals of 20 artificial maxillary molars were assigned into two groups (n=30 root canals) according to the access cavity design used: Group I: traditional access cavity (TAC) and Group II: conservative access cavity (CAC). CBCT scans of samples were made before and after root canal preparation using the RECIPROC blue rotary system. The shaping parameters are evaluated in root canal transportation and the centering ability. Three CBCT sections per tooth were analyzed at 3, 6, and 9 mm from the apex to assess the canal transportation and centering ability at three levels, apical, middle, and coronal thirds. Data were analyzed using the GraphPad Prism (GraphPad Software, San Diego, CA). Results The results of this study showed a significant difference in transportation within the coronal and middle thirds. However, in apical thirds, there were no significant differences. Both groups observed a significant difference in the centering ability in the coronal third. Conclusion Within the limitations of this study, CAC can be recommended with caution as an alternative access to TAC.

Comparison of hand, rotary, reciprocating and self-adjusting files in cleaning mesio-buccal canals of maxillary first molars.

The smear layer removal capability of different instrumentation techniques on the mesio-buccal root canals of maxillary first molars is of interest to dentists. Sixty extracted maxillary first molars with fully developed apices, curved root canals, and curvatures between 30 to 45 degrees were selected. The teeth were divided into four groups (n=15) based on the instrumentation technique used. The samples were analyzed using a thermal field emission scanning electron microscope to assess smear layer removal at the apical, middle, and coronal thirds of the canals. The Wave One file system showed superior performance in smear layer removal across all three regions of the canal compared to hand files, Hyflex CM rotary files and SAF.

Gender-Specific Variations in Greater Palatine Foramen Anatomy: Insights from CBCT Scans in the North Cyprus Population.

BACKGROUND The greater palatine foramen (GPF) is anatomically located distal to the third maxillary molar tooth, midway between the midline of the palate and the dental arch. The GPF contains the major palatine artery, vein, and nerve, traversing the palatine sulcus. This study aimed to evaluate the anatomical position of the GPF in 93 women and 67 men at a single center in Cyprus using cone beam computed tomography (CBCT). MATERIAL AND METHODS A retrospective analysis was conducted on 160 CBCT scans. Measurements of the GPF's horizontal and vertical diameters, distances from GPF to the incisive foramen, posterior nasal spine, anterior nasal spine, and midaxillary suture, and positional relationships to molars were recorded. Statistical analyses compared these measurements between males and females. RESULTS The study included 93 females and 67 males with an average age of 46.6 (±11.6) years. Significant sex differences were observed in most GPF measurements, with males showing larger dimensions such as the anterior nasal spine, posterior nasal spine, mid-maxillary suture, and incisive foramen to the GPF. The GPF was predominantly located in the third molar region (96.25% on the right, 96.9% on the left). The left GPF showed a significantly larger horizontal diameter than the right (P<0.05). CONCLUSIONS There was a significant difference in the average distances from the anterior nasal spine, posterior nasal spine, mid-maxillary suture, and incisive foramen to the GPF, as well as in the size of the GPF, between males and females. Recognizing these variations enhances clinical planning and reduces the risk of complications.

Proposal for a grading system to determine the clinical status and sequence of permanent teeth eruption: A pilot study

ObjectivesThe objective of the study was to propose and test a new grading system to quantify the clinical eruption of teeth into the oral cavity. In addition, the study also aimed to apply the grading system to a sample population to determine the chronology and sequence of permanent tooth eruptions, comparing the results with an existing standard table. MethodsA cross-sectional study was designed, and 1220 children aged 5–18 years were selected from five schools in Chennai. The clinical status of permanent tooth eruption was graded using the newly proposed system. The sequence and chronology of permanent tooth eruptions were determined using Probit analysis and compared with those established by Logan and Kronfeld. The difference in stages of eruption between the sexes was analyzed using the ANOVA test. ResultsThe study sample included 515 boys and 705 girls. A total of 23,218 permanent maxillary and mandibular teeth were examined and graded. Of the 11,085 maxillary teeth, 367 were classified as grade 1, 660 as grade 2, and 10,058 as grade 3. Similarly, of the 12,133 mandibular teeth, 497 were grade 1, 793 were grade 2, and 10,843 were grade 3. The eruption of the maxillary canines, second molars, and mandibular second premolars was observed to have occurred earlier than in the traditional table of tooth eruption. The most significant differences in the stages of eruption between the sexes were observed in the 9–12 age group. ConclusionsThe newly proposed grading system was found to be simple, objective, less confusing, and more robust, compared with the existing systems in determining the clinical status of tooth eruptions. The ages of eruption of maxillary canines, second molars, and mandibular second premolars were earlier.

Endodontic radiography - what’s displaying the radiograph? The yield of commercial computer screens vs. DICOM calibrated medical screens in endodontic radiography

ObjectiveA comparison between commercial computer screens and DICOM-calibrated medical screens for characterizing anatomy and diagnosing dental pathologies was performed. The aim of this study was to evaluate and compare the ability of each of those screens to identify root apices and widening of the periodontal ligament (PDL) in the posterior maxillary area.Materials and MethodsDigital X-ray images of 53 maxillary molar teeth were examined by means of a commercial computer screen and again two months later with a DICOM screen to compare their ability to help identify and diagnose PDL widening and to locate the root apices of those teeth.ResultsThe DICOM screen had a significantly better ability to identify widened PDLs (from 31.4% to 34.8% of the cases compared to 19% to 26.1% for the commercial screens, P < .001), depending upon the observer. The DICOM screen was also significantly superior in depicting the root apices compared to the commercial screens (from 77.4% to 83.6% of the cases compared to 56% to 66.7% for the commercial screens, P < 0.001), depending upon the observer.ConclusionDICOM-calibrated medical screens were significantly superior to commercial computer screens for identifying widened PDLs and locating the root apex in the posterior maxillary area.

Combined Effects of Fibroblast Growth Factor-2 and Carbonate Apatite Granules on Periodontal Healing: An In Vivo and In Vitro Study.

The aim of this study was to investigate in vivo and in vitro the effectiveness of the use of fibroblast growth factor (FGF)-2 with carbonate apatite (CO3Ap) on periodontal healing. Periodontal defects created in the maxillary first molars in rats were treated with FGF-2, CO3Ap, FGF-2 + CO3Ap or left unfilled. Healing was evaluated using microcomputed tomography, histological, and immunohistochemical analyses. In vitro experiments were performed to assess cellular behaviors and the expression of osteoblastic differentiation markers in MC3T3-E1 cells. At 4 weeks, the bone volume fraction in the FGF-2 + CO3Ap group was significantly greater than that in the CO3Ap group, but there was no significant difference from the FGF-2 group. The FGF-2 + CO3Ap group demonstrated greater new bone compared with the FGF-2 or CO3Ap group. The FGF-2 + CO3Ap group showed greater levels of osteocalcin-positive cells compared with the CO3Ap group, but there was no significant difference from the FGF-2 group. In vitro, the FGF-2 + CO3Ap group exhibited a greater extent of cell attachment and more elongated cells compared with the CO3Ap group. Compared with the CO3Ap group, the FGF-2 + CO3Ap group showed significantly higher viability/proliferation, but the expressions of Runx2 and Sp7 were reduced. The results indicated that the use of FGF-2 with CO3Ap enhanced healing in the periodontal defects. FGF-2 promoted cell attachment to and proliferation on CO3Ap and regulated osteoblastic differentiation, thereby contributing to novel bone formation.

Management of dislodged crown using split cast metal post and core: A case report

Across diverse cultures, the practice of restoring lost tooth structure has endured through generations. It is widely understood that merely undergoing quality endodontic therapy is not sufficient to fully restore a severely weakened tooth with pulpal disease. Equally crucial is ensuring post-endodontic restoration followed by quality prosthetic rehabilitation. In instances where a tooth is extensively damaged, utilizing a post becomes the preferred course of action post endodontic treatment to preserve the core. The gold standard for the treatment of a severely compromised tooth is recognized as a cast post and core. In this case study, a previously treated maxillary first molar, which had a dislodged fiber post and core along with a porcelain-fused-to-metal (PFM) crown, underwent retreatment with a split cast metal post and core followed by a PFM crown.

Effectiveness of Clear Aligners on Sequential Maxillary Molar Distalization: Discrepancy between Treatment Goal and Outcome.

Objectives: The purpose of this preliminary study was to determine the differences between planned and actual maxillary molar movements after the completion of treatment with an initial set of clear aligners including sequential maxillary molar distalization. Methods: The data records of 14 non-growing patients who completed orthodontic treatment with sequential maxillary molar distalization using clear aligners were retrospectively evaluated (n= 14, 4 males and 10 females, 33.61 ± 8.57 years). Data on planned tooth movements were obtained from ClinCheck software (ClinCheck Pro version 5.3). The amounts of actual tooth movements were obtained by performing superimposition of lateral cephalograms taken before and after treatment. The amounts of distal translation and tipping between planned and actual maxillary molar movements were compared with the paired Student's t-test. Results: The statistically significant differences between planned and actual translation movements of maxillary first and second molars were shown after completing treatment with the first series of aligners (p < 0.05). The average actual amount of molar distalization on maxillary first molars was less than the planned amount by 1.32 ± 0.42 mm. Similarly, the average actual amount of molar distalization on maxillary second molars was less than the planned amount by 1.57 ± 0.45 mm. The accuracy for molar distalization, namely, the percentage of actual distal translation to planned movement, was 40.11% for maxillary first molars and 35.39% for maxillary second molars. However, the difference between the planned and actual angulation movements was not significant (p > 0.05). Conslusions: In conclusion, the amounts of actual distal translation of maxillary molars through the utilization of clear aligners were significantly lower than planned. However, there were no statistically significant differences between the degrees of actual and planned molar angulation movement.

The effect of adding chitosan nanoparticles on different properties of the adhesive and high-filled composite resin

PurposeTo evaluate the effect of adding nano-chitosan on different properties of the adhesive and high-filled flowable composite resin (viewing the graphical abstract is suggested). BackgroundIncorporating chitosan might improve the quality of adhesive and high-filled composite resin used in the deep margin elevation (DME) and other restorative methods. Materials and methodsTwo groups of composite disks (without chitosan, with 1 % chitosan) were created to evaluate antimicrobial effects, degree of conversion (DC), solubility and water sorption. Antimicrobial activity was evaluated through biofilm inhibition and disk agar diffusion tests while DC was analyzed using FTIR. For the microshear bond strength test (μSBS), extracted maxillary molars were sectioned 1 mm under the CEJ, undergoing immediate dentin sealing and DME in four groups: control, pretreatment chitosan application, adhesive+1 % chitosan, and composite+1 % chitosan. The forces and the modes of failure were recorded. ResultsAdding chitosan nanoparticles increased the antimicrobial activity, significantly (p < 0.05). The μSBS and DC did not differ significantly between the groups (p > 0.05), and the failures were mostly found in the adhesive mode. The solubility and water sorption increased significantly (p < 0.05), remaining in a clinically acceptable range though. ConclusionAdding chitosan could be a potential option to increase the antibacterial effect in the high-filled composite resin without any negative affect on μSBS or DC, and clinically unacceptable effect on solubility and water sorption. (The graphical abstract has been provided). Clinical significanceAdding chitosan nanoparticles to high-filled flowable composite resin, increases the success rate of related restorative technique by adding the antimicrobial effect without any significant negative influence on other biomechanical properties.

Effects of Nitrate and Nitrite on Plaque pH Decrease and Nitrite-Producing and -Degrading Activities of Plaque in vitro.

The purpose of this study was to investigate the effects of nitrate and nitrite on the pH-lowering activity of human plaque, the nitrite-producing and -degrading activities of human plaque, and their correlation. Nitrate and nitrite were added to human plaque suspensions collected from the buccal aspect of maxillary molars of patients visiting a general dental clinic, and changes in pH were measured with and without glucose addition. Nitrite-producing and -degrading activities were evaluated by adding nitrate and nitrite to the plaque suspension and measuring the increase and decrease in nitrite with Griess reagent, respectively. The addition of nitrate inhibited both endogenous and glucose-induced plaque pH-lowering. The addition of glucose enhanced the production of nitrite from nitrate by about 3.3-fold. The addition of nitrite also inhibited endogenous plaque pH-lowering, but the addition of glucose promoted nitrite degradation by only about 1.1-fold. Nitrite-producing activity was positively correlated with age, but not with nitrite-degrading activity. This study revealed that nitrite was produced from nitrate and inhibited the pH-lowering activity of human plaque, which may contribute to caries control. Both nitrite-producing and -degrading activities occurred in human plaque, but no correlation was found between them. Furthermore, nitrite production was enhanced by glucose metabolism, which may function as a self-regulatory mechanism (resilience) to prevent excessive acidification by glucose metabolism.

Disparate effects of sclerostin deletion on alveolar bone and cellular cementum in mice.

Cellular cementum (CC) includes cementocytes, cells suspected to regulate CC formation or resorption as osteocytes do in bone. Sclerostin (SOST) is a secreted negative regulator of Wnt/β-catenin signaling expressed by osteocytes andcementocytes. Osteocyte SOST expression reduces bone formation. We investigated the functional importance of SOST in CC compared with alveolar bone (AB) using a Sost knockout (Sost-/-) mouse model to better understand the role of cementocytes in CC. Mandibles and femurs of Sost-/- and wild-type (WT) mice were analyzed at 42 and 120 days postnatal (dpn). Maxillary first molars were bilaterally extracted at 42 dpn and both AB healing (maxillary molar sockets) and CC apposition (mandibular first molars) were examined at 21 days post-procedure. Analyses included micro-computed tomography, histology, and immunohistochemistry. Femur cortical and trabecular bone and mandibular bone volumes were similarly increased in Sost-/- versus WT mice at 42 and/or 120 dpn. In contrast to previous reports, CC was not increased by Sost-/- at either age. We conducted challenge experiments on AB and CC to explore tissue-specific responses. Post-extraction AB healing was improved by Sost deletion. In contrast, experimentally-induced apposition in molars failed to stimulate increased CC formation in Sost-/- versus WT mice. Wnt pathway markers AXIN2 and DKK1, which were increased in Sost-/- versus WT AB osteocytes, were unchanged in cementocytes. These data indicate CC is less responsive than AB to SOST deletion. Within the study limitations, these results do not support cementocytes as critical for directing increased CC formation. Sclerostin is a protein known to inhibit bone formation, and removing sclerostin leads to more bone formation. Cementum is the thin layer that covers the surface of the tooth's root. Previous studies suggest that inhibiting sclerostin can similarly increase the amount of cementum. We wanted to compare the response of cementum and bone when sclerostin is absent to understand similarities and differences between these two tissues. In this study, we removed the Sost gene (the gene which produces sclerostin) in mice. We found that mice without sclerostin have more bone in their legs and jaws. Moreover, mice without sclerostin also healed better after tooth removal compared with normal mice. Surprisingly, unlike previous studies, we found that the amount of cementum was not different in mice without sclerostin compared with normal mice. Additionally, we challenged the cementum by taking out the opposing tooth to cause the first mandibular molar to move up by building more cementum. Even with this challenge, we found no difference in the amount of cementum in mice lacking sclerostin compared with normal mice. Therefore, we conclude here that cementum is less sensitive to the absence of sclerostin compared with bone.

Interdisciplinary treatment of a mutilated dentition with multiple missing teeth and horizontal impaction of a mandibular third molar using an orthodontic skeletal anchorage and dental implants-Case report.

This case report presents a female adult patient who exhibits poor oral hygiene, a mutilated dentition with multiple missing teeth, and skeletal asymmetry. Interdisciplinary treatment was necessary to maintain oral hygiene, treat caries, extract residual roots, and upright a horizontally impacted third molar using a miniplate. Additionally, orthodontic mini-implants were utilized as anchorage to improve sagittal relationship and space closing. Space management was completed with orthodontic treatment, followed by restoration of the multiple missing teeth with dental implants. Consequently, an esthetic smile and functional occlusion were achieved by interdisciplinary treatment using orthodontic skeletal anchorage devices and dental implants. Missing mandibular first molar spaces were closed with retraction of the anterior teeth and protraction of the mandibular second molars using orthodontic mini-implants. The mandibular right third molar, which should have erupted, was protracted with the second molar, while the horizontally impacted mandibular left third molar was uprighted using a miniplate and was protracted with an orthodontic mini-implant. The missing maxillary lateral incisors were replaced with the maxillary canines, and the maxillary canines were replaced with the maxillary first premolars. The missing maxillary right second premolar and first molar and left first and second molars were successfully restored with dental implants.

Tip, torque and rotation of maxillary molars during distalization using Invisalign: a CBCT study

BackgroundDesirable molar distalization by bodily movement is challenging and can be difficult to achieve. This study investigated changes in molar angulation (mesiodistal tipping), molar inclination (buccolingual torque) and rotation during distalization using clear aligner therapy (CAT).Materials and methodsThis retrospective study included 38 cone beam computed tomographic images (CBCTs) taken for patients treated with molar distalization using CAT. The study evaluated pre- (T0) and post-treatment (T1) CBCTs of 19 adult patients (36.68 ± 13.50 years) who underwent maxillary molar distalization using Invisalign® aligners (Align Technology, Inc., San José, CA, USA) with a minimum of 2 mm distalization. Changes in maxillary molar tip, torque and rotation were measured for 61 molars (183 roots). Paired t-test was used to evaluate the differences between pre- and post-treatment readings. The level of significance was set at p ≤ 0.05. The reproducibility of measurements was assessed by the intraclass correlation coefficient (ICC).ResultsMolar angulation did not show significant change after distalization (p = 0.158) however, there was significant increase in buccal molar inclination (p = 0.034) and mesiobuccal molar rotation (p < 0.001).ConclusionMolar distalization of 2 mm did not cause significant molar tipping. Maxillary molars showed significant buccal inclination (increased torque) and mesiobuccal rotation after distalization.

Systemic administration of propranolol reduces bone resorption and inflammation in apical periodontitis of chronically stressed rats.

To evaluate the effect of systemic administration of propranolol on the severity of apical periodontitis (AP) in chronically stressed rats. Twenty-four 70-day-old male Wistar rats (Rattus norvegicus, albinus) were distributed into three groups (n = 8): rats with AP without stressful conditions (AP-Control), rats with AP and submitted to a chronic unpredictable stress (CUS) protocol (AP + S) and rats with AP and submitted to a CUS protocol treated with propranolol (AP + S + PRO). Stress procedures were applied daily until the end of the experiment. After 3 weeks of CUS, AP was induced in all groups by exposing the pulpal tissue of mandibular and maxillary first molars to the oral environment. Propranolol treatment was administered orally once a day for the entire period of the experiment. Rats were sacrificed at 42 days, and the blood was collected for stress biomarkers serum dosage by multiplex assay. Mandibles were removed and submitted to microtomography and histopathological analyses. Periapical tissue surrounding the upper first molar was homogenized and subjected to RT-PCR analysis to evaluate the mRNA expression of RANKL, TRAP and OPG. Parametric data were assessed using one-way ANOVA followed by Tukey's test while the nonparametric data were analysed by the Kruskal-Wallis followed by Dunn's test. Significance level was set at 5% (p < .05) for all assessed parameters. Micro-CT revealed statistically significant differences in bone resorption which was greater in the AP + S group (p < .05), but no differences were observed between the Control and AP + S + PRO groups (p > .05). The AP + S + PRO group had a lower intensity and extent of inflammatory infiltrate compared to the AP + S group with smaller areas of bone loss (p < 0.05). The gene expression of RANKL and TRAP was significantly higher in the stressed group AP + S compared to the control group (p < .05), and a significantly higher OPG expression was observed in AP + S + PRO compared to the AP + S group (p < .05). Oral administration of propranolol had a significant effect on the AP severity in stressed rats, suggesting an anti-inflammatory effect and a protective role on bone resorption of AP in stressed animals. Further research is necessary to fully comprehend the underlying mechanisms.

Impact of concentrated growth factor (CGF) injection on acceleration of orthodontic tooth movement in rabbits

BackgroundThe present study aimed to assess how a concentrated growth factor (CGF) injection affects the rate of orthodontic tooth movement in rabbits.MethodsThis experimental investigation employed a split-mouth configuration. Before orthodontic mesialization of the maxillary first molars, CGF was prepared and administered using submucosal injections on the buccal and palatal sides of the maxillary first molars in one randomly assigned quadrant. The opposite quadrant was used as a control. The study examined four time points:1, 2, 3, and 4 weeks. The measurement of tooth movement was conducted at each follow-up point using a digital caliper. The rabbits were euthanized, and their maxillary segments, specifically the maxillary first molars, were studied histologically to identify any alterations occurring on both the tension and compression sides.ResultsSignificant tooth movement was observed in the experimental sides versus control sides in the second, third, and fourth week of follow-up periods (p ≤ 0.05). Histologically, on the compression side, the CGF group showed bone resorption and periodontal ligament active reactions from the first week and continued throughout the next three weeks. Also, on the tension side, the CGF group depicted cementoblastic and osteoblastic activities from the first week followed by fibroblastic activities from the second week and all activities continued till the fourth week.ConclusionsCGF has the potential to effectively enhance orthodontic tooth movement without adverse clinical or histological effects.

Soft tissue inflammation around upper third molar cause limited mouth opening: common but overlooked.

The aim of this study was to explore inflammation of soft tissue around the upper third molar as a prevalent cause of limited mouth opening, identify the clinical and radiographic features, and summarize the therapeutic effectiveness of tooth extraction. A retrospective analysis of data from 264 patients with limited mouth opening over the last five years was performed. Among the 264 patients, 24 (9.1%) had inflammation of the soft tissue around the upper third molar, which was the second most common cause of limited mouth opening. Twenty-one of the twenty-four affected patients, with an average mouth opening of 19.1 ± 7.6mm, underwent upper third molar extraction. Gingival tenderness around the upper third molar or maxillary tuberosity mucosa was a characteristic clinical manifestation (p < 0.05). The characteristic features on maxillofacial CT included soft tissue swelling around the upper third molar and gap narrowing between the maxillary nodules and the mandibular ascending branch. Post extraction, the average mouth opening increased to 31.4 ± 4.9mm (p < 0.05), and follow-up CT demonstrated regression of the inflammatory soft tissue around the upper third molar. Inflammation of soft tissue around the upper third molar is a common cause of limited mouth opening. Symptoms of pain associated with the upper third molar and distinctive findings on enhanced maxillofacial CT scans are crucial for diagnosis. Upper third molar extraction yields favorable therapeutic outcomes. Inflammation of the soft tissue around the maxillary third molar commonly causes limited mouth opening, but this phenomenon has long been overlooked. Clarifying this etiology can reduce the number of misdiagnosed patients with restricted mouth opening and enable more efficient treatment for patients.

Virtual bracket removal: a comparative assessment of different software packages

BackgroundHigh precision intra-oral scans, coupled with advanced software, enable virtual bracket removal (VBR) from digital models. VBR allows the delivery of retainers and clear aligners promptly following debonding, thus reducing the patients' appointments and minimizing the likelihood of tooth movement. The objective of this study was to compare the enamel surface before bonding and after VBR using three different Computer-aided design (CAD) software and to compare their accuracy.MethodsMaxillary scans of 20 participants starting orthodontic treatment were selected for inclusion in the study, who exhibited mild to moderate crowding and required bonding of brackets on the labial surface of permanent maxillary teeth (from the maxillary left first molar to the maxillary right first molar). Two intra-oral scans were conducted on the same day, before bonding and immediately after bonding using CEREC Omnicam (Sirona Dental Systems, Bensheim, Germany). The virtual removal of the brackets from the post-bonding models was performed using OrthoAnalyzer (3Shape, Copenhagen, Denmark), Meshmixer (Autodesk, San Rafael, Calif, USA), and EasyRx (LLC, Atlanta, GA, USA) software. The models that underwent VBR were superimposed on the pre-bonding models by Medit Link App (Medit, Seoul, South Korea) using surface-based registration. The changes in the enamel surface following VBR using the three software packages were quantified using the Medit Link App.ResultsThere was a significant difference among the 3Shape, Meshmixer, and EasyRx software in tooth surface change following VBR. Specifically, EasyRx exhibited lower levels of accuracy compared to the other two VBR software programs (p<.001, p<.001). A significant difference in enamel surface change was observed between tooth segments across all software groups, in both incisors and molars, with VBR of the molars exhibiting the lowest level of accuracy (3Shape p=.002, Meshmixer p<.001, EasyRx p<.001). Regarding the direction of tooth surface changes following VBR, it was observed that all three groups exhibited a significant increase in the percentage of inadequate bracket removal across all teeth segments.Conclusions3Shape and Meshmixer manual VBR software were found to be more accurate than EasyRx automated software, however, the differences were minimal and clinically insignificant.