Cone beam computed tomography assessment of maxillary anterior teeth cervix dimensions in healthy adults for optimal anatomic healing abutments.

OBJECTIVES: The abutments produced with circular symmetry failed to accurately replicate the natural teeth's cervical shapes. The purpose of this study was to measure cervical cross-sections of maxillary anterior teeth using cone beam computed tomography (CBCT) images to design anatomic healing abutments. MATERIALS AND METHODS: CBCT data of 61 patients were analyzed using Ez3D Plus software. Measurements were taken at the cemento-enamel junction (CEJ) and 1 mm coronal to CEJ for maxillary central incisors, lateral incisors, and canines. Various parameters, including area, perimeter, and eight line segments in the distal (a), disto-palatal (b), palatal (c), mesio-palatal (d), mesial (e), mesio-labial (f), labial (g), and disto-labial (h) directions, were used to describe dental neck contours. The ratios (f/b and h/d) were analyzed, and differences based on sex and dental arch morphology were explored. RESULTS: Significant differences were found in area and perimeter between males and females, but not in f/b and h/d ratios. Differences in the f/b ratio were observed among dental arch morphologies for maxillary central incisors, lateral incisors, and canines. CONCLUSIONS: CBCT measurements of cervical cross-sections provide more accurate data for designing anatomic healing abutments. The fabrication of anatomical healing abutments needs to consider the influence of gender on cervical size and to explore the potential effect of arch shape on cervical morphology. CLINICAL SIGNIFICANCE: The novel method provides detailed measurements for the description of dental cervical contours for patients with bilateral homonymous teeth missing. The measurements of this study could be utilized to design more accurate anatomic healing abutments to create desired morphology of peri-implant soft tissue.

Effects of functional mandibular lateral shift on craniofacial growth and development in growing rats.

BACKGROUND: Unilateral posterior crossbite, one of the most frequent malocclusions, is often associated with functional lateral shift of the mandible. Although the effects of functional lateral shift on the mandible and temporomandibular joint have been examined in various animal experiments, cranial and maxillary changes have received less attention. OBJECTIVE: The aim of this study was to investigate the effects of functional lateral shift on the craniofacial complex in growing rats. METHODS: Eighty 5-week-old male Sprague-Dawley rats were randomly divided into an experimental group (n = 40), which received an oblique guide appliance that shifted the mandible to the left during closure, and a control group (n = 40). The rats were scanned by cone-beam computed tomography at 3 days and 1, 2, 4 and 8 weeks. The dimensions of the mandibular bone, condyle, maxilla and cranium were measured. RESULTS: The mandibles of rats in the experimental group were smaller than those of the rats in the control group and were asymmetrical. The condyles of the rats in the experimental group were thinner than those of the control rats. The condylar length on the ipsilateral side was shorter and wider than that on the contralateral side from 4 to 8 weeks. No significant differences in cranial length or height were observed between the experimental and control groups. The height of the upper first molar and alveolar bone on the contralateral side was significantly smaller than that on the ipsilateral side and in the controls from 4 to 8 weeks. CONCLUSION: Functional shift in the mandible produces morphological asymmetries in the mandible and maxillary region and may cause bilateral condylar degenerative changes.

Abnormal eruption of teeth in relation to FGFR1 heterozygote mutation: a rare case of osteoglophonic dysplasia with 4-year follow-up.

BACKGROUND: We report a case and its 4-year follow-up of Osteoglophonic dysplasia (OD), a rare disease that disturbs both skeletal and dental development, which is usually caused by heterozygous FGFR1 mutations. CASE PRESENTATION: This article presents a case where a 6-year-old male patient suffered dysregulation of tooth eruption and was diagnosed with osteogenic dysplasia from a fibroblast growth factor receptor 1 (FGFR1) heterozygote mutation. However, the number of teeth is within the normal range, and their roots are well developed. Several interventions were implemented with varying degrees of results. The details of the 4-year follow-up showed that the signs of OD were more pronounced, including dwarfism, frontal bossing, delayed skeletal maturation, anteverted nares, micrognathia, and prominent ears, but the patient's impacted teeth and edentulous jaws remained unchanged. CONCLUSIONS: FGFR1 heterozygote mutation and OD present significant difficulty for teeth eruption and subsequent intervention. Further measures ought to be taken in recognizing various symptoms presented by the patient. This case supports the significance of careful inquiry, comprehensive physical examination and correct diagnosis as indispensable steps for clinical practice in patients with unerupted teeth. Additionally, the detailed case and its 4-year follow-up length may provide new insights into osteogenic dysplasia and patients with impacted teeth while encouraging further exploration in treatment methods.

Stress overload-induced periodontal remodelling coupled with changes in high mobility group protein B1 during tooth movement: an in-vivo study.

High mobility group protein B1 (HMGB1), a bone-active cytokine and an osteocyte alarmin, might have dual functions in bone metabolism that could benefit bone formation and accelerate osteoclastogenic activity. High mobility group protein B1 was recently shown to be involved in tooth movement. Here, we investigated the expression of HMGB1, which remains poorly elucidated, under stress overload-induced periodontal remodelling conditions in vivo. Thirty-six Sprague-Dawley rats (male, 180-200 g) were randomly divided into three groups: two experimental groups, in which 50 or 100 g of force was applied to the first molars for 7 d to induce movement; and one control group, in which no force was applied. These stresses induced tooth movement over significantly different distances, and marked morphological changes were consistently observed in the periodontal tissues of the experimental rats, as demonstrated by histological staining. A real-time PCR analysis showed upregulation of the receptor activator of nuclear factor-kappaB ligand-to-osteoprotegerin ratio and downregulation of the Hmgb1 gene. Changes in both location and expression of the HMGB1 were observed through immunofluorescence analysis. Our data suggest that HMGB1 expression during orthodontic tooth movement might be regulated in a time- and force-dependent manner that is substantially more complex than anticipated.

The dynamic progression of temporomandibular joint osteoarthritis-like lesions elicited by mandibular shift in a rat model.

BACKGROUND: Temporomandibular joint osteoarthritis (TMJ-OA) presents significant challenges due to its complex etiology, often insidious onset, high incidence, and progressive structural deterioration. While research has explored genetic and molecular factors, treatment outcomes remain suboptimal, emphasizing the need for a deeper understanding of disease progression. OBJECTIVE: This study employs a specific mandibular shift rat model to explore the dynamic progression of TMJ-OA-like lesions and evaluate the potential for self-repair at different stages, aiming to inform early diagnosis and preventative strategies. METHODS: Seventy-two female Sprague-Dawley rats were randomized into three groups: a control group (n=24; average weight: 157.23±1.63 g) receiving sham surgery. an experimental group (n=24; average weight: 157.78±1.88 g) subjected to mandibular shift induction, and a removal group (n=24; average weight: 158.11±2.20 g) experiencing mandibular shift for one, two, or four weeks followed by a one-month recovery period (designated as 1w Removal, 2w Removal and 4w Removal, respectively). Histomorphological and molecular analyses were conducted at designated time points. RESULTS: Rats in the 1-week removal group exhibited substantial recovery in condylar morphology, cartilage thickness, extracellular matrix composition, and expression of OA-related genes. Conversely, the 4-week removal group mirrored the experimental group, indicating limited self-repair capacity at later stages. The 2-week removal group presented with variable outcomes, with some animals showing signs of recovery and others resembling the experimental group, indicating a potential transitional phase in the disease process. CONCLUSION: Recovery from early-stage TMJ-OA involves eliminating provoking factors such as occlusal interference or reducing joint loading. However, advanced stages exhibit diminished self-repair capabilities, necessitating additional therapeutic interventions. These findings emphasize the importance of early diagnosis and intervention in TMJ-OA management.

Targeting G6PD to mitigate cartilage inflammation in TMJOA: The NOX4-ROS-MAPK axis as a therapeutic avenue.

Chondrocytes, known for their metabolic adaptability in response to varying stimuli, play a significant role in osteoarthritis (OA) progression. Glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme of the pentose phosphate pathway, has recently been found to upregulate in OA chondrocyte. However, the exact role of G6PD in temporomandibular joint osteoarthritis (TMJOA) and its effect on chondrocyte function remains unclear. In present study, we induced OA-like conditions in the rat temporomandibular joint via occlusal disharmony (OD), noting a marked increase in G6PD expression in the condylar cartilage. Our data show that G6PD knockdown in mandibular condylar chondrocytes (MCCs) reduces the expression of catabolic enzymes (e.g., MMP3, MMP13) and inflammatory cytokines (e.g., IL6) induced by IL-1ß. G6PD knockdown also mitigates IL-1ß-induced upregulation of ERK, JNK, and p38 phosphorylation and reduces reactive oxygen species (ROS) levels by decreasing the nicotinamide adenine dinucleotide phosphate (NADPH) and NADPH oxidases 4 (NOX4) mRNA expression. In summary, G6PD appears to regulate the inflammatory state of condylar chondrocytes via the NOX-ROS-MAPK axis, highlighting its potential as a therapeutic target for TMJOA.

Effect of sulfonation time on physicochemical, osteogenic, antibacterial properties and biocompatibility of carbon fiber reinforced polyether ether ketone.

The carbon fiber reinforced polyetheretherketone (CFR-PEEK) has been increasingly used in orthopedics dentistry due to its excellent biocompatibility and mechanical properties. However, the biological inertness and poor antibacterial activity limit its clinical applications. This paper focused on the performances of CFR-PEEK with porous morphology that were exposed to different sulfonation periods (1, 3, 5, and 10 min, corresponding to CP-S1, CP-S3, CP-S5, and CP-S10, respectively). Residual sulfuric acid was removed by acetone rinsing, NaOH immersion, and hydrothermal treatment before in vitro and in vivo studies. The results showed some significant difference in the physicochemical properties, including energy dispersive X-ray spectroscopy (EDS) map of sulfur atoms, X-ray photoelectron spectroscopy (XPS) of valences of sulfur ions, Fourier transformation infrared spectroscopy (FTIR), hydrophilicity, hardness, and elastic modulus among CP-S3, CP-S5, and CP-S10. However, CP-S5 and CP-S10 were more effective in promoting the proliferation, adhesion, and osteogenic differentiation of seeded bone mesenchymal stem cells (BMSCs) and growth inhibition of S. aureus and P. gingivalis compared with other groups. Furthermore, the CP-S5 and CP-S10 samples achieved better cranial bone repair than the non-sulfonation group in a rat model. Therefore, it can be inferred that both 5 and 10 min are viable sulfonation durations for 30% CFR-PEEK. These findings provide a theoretical basis for developing CFR-PEEK for clinical applications.

BNTA attenuates temporomandibular joint osteoarthritis progression by directly targeting ALDH3A1: An in vivo and in vitro study.

BNTA is known to have a therapeutic effect on knee osteoarthritis and inflammatory osteoclastogenesis. However, the protective effect of BNTA regarding temporomandibular mandibular joint osteoarthritis (TMJOA) and its underlying mechanism and physiological target remains unclear. In the present study, BNTA ameliorated cartilage degradation and inflammation responses in monosodium iodoacetate (MIA)-induced TMJOA in vivo. In IL-1ß-induced condylar chondrocytes, BNTA prevents oxidative stress, inflammatory responses and increasing synthesis of cartilage extracellular matrix through activating nuclear factor-E2-related factor 2 (NRF2) signaling. Suppression of NRF2 signaling abolishes the protective effect of BNTA in TMJOA. Notably, BNTA may bind directly to ALDH3A1 and act as a stabilizer, as evidenced by drug affinity responsive target stability assay (DARTS), cellular thermal shift assay (CETSA) and molecular docking results. Further investigation of the underlying molecular and cellular mechanism infers a positive correlation of ALDH3A1 regulating NRF2 signaling. In conclusion, BNTA may attenuate TMJOA progression via the ALDH3A1/NRF2 axis, inferring that BNTA is a therapeutic target for treating temporomandibular mandibular joint osteoarthritis.

Experimental functional shift-induced osteoarthritis-like changes at the TMJ and altered integrin expression in a rat model.

Mandibular deviation affects the biomechanical environment of the temporomandibular joint (TMJ) and causes thinning of cartilage on the deviated side. We aimed to evaluate, using a rat model, the effect of mandibular functional deviation on the TMJ in relation to the functional roles of integrin ß family members. The effects of experimental functional deviation on the TMJ of 6-week-old Sprague-Dawley female rats, randomly assigned to control (n = 42) and experimental groups (n = 42), were evaluated at 3 days and 1, 2, 4, and 8 weeks by histological staining, immunofluorescence, real-time quantitative polymerase chain reaction, and micro-computed tomography. The results showed that the experimental functional shift changed the shape of condyles, thinned the cartilage, and increased the proportion of the hypertrophic layer on the deviated sides of condyles. In addition, the extracellular matrix of the condyle cartilage exhibited degradation at 1 week and subchondral trabecular bone was lost at 4 and 8 weeks. Osteoarthritis (OA)-like changes occurred in the left and right condyles of rats in the experimental group and were aggravated over time. Integrin ß family expression, especially integrin ß2 , was altered from week 1, possibly related to the OA-like changes. These data may provide insight into the onset of TMJ OA.

Mechanical stress reduces secreted frizzled-related protein expression and promotes temporomandibular joint osteoarthritis via Wnt/ß-catenin signaling.

AIMS: Mechanical stress overload in the temporomandibular joint (TMJ) is an important cause of TMJ osteoarthritis (TMJOA). Whether secreted frizzled-related proteins (SFRPs) play important roles in the development of mechanical stress-induced TMJOA remains controversial. In this study, we investigated the roles of the Wnt/ß-catenin signaling and SFRPs in the progression of mechanical stress-induced TMJOA. METHODS: We investigated the progression of mechanical stress-induced TMJOA using an in vivo model via modified increased occlusal vertical dimension (iOVD) malocclusion and an in vitro model in which isolated chondrocytes were subjected to mechanical stress. The effects of inhibition of Wnt/ß-catenin signal on TMJOA induced by mechanical stress were studied by in vitro drug added and in vivo intra-articular injection of XAV-939. TMJOA progression, Wnt/ß-catenin signaling and SFRPs was assessed by Cone beam computed tomography (CBCT) analysis, histochemical and immunohistochemical (IHC) staining, quantitative real-time PCR (qRT-PCR), Western blotting (WB), and immunofluorescence (IF) staining. RESULTS: Our in vivo results showed that iOVD-induced mechanical stress in the TMJ disrupted mandible growth, induced OA-like changes in TMJ cartilage, and increased OA-related cytokine expression. In addition, iOVD activated Wnt/ß-catenin signaling and suppressed Sfrp1, Sfrp3, and Sfrp4 expression in condylar cartilage. Moreover, our in vitro study showed that stress disrupted homeostasis, activated Wnt/ß-catenin signaling and inhibited SFRP3 and SFRP4 expression in chondrocytes. Suppression of Wnt/ß-catenin signaling with XAV-939 promoted SFRP3 and SFRP4 expression and rescued mechanical stress-induced cartilage degeneration in vivo and in vitro. CONCLUSIONS: Our work suggests that mechanical stress reduces SFRPs expression both in vivo and in vitro and promotes TMJOA via Wnt/ß-catenin signaling. Suppression of Wnt/ß-catenin signaling promotes SFRPs expression, especially SFRP3 and SFRP4 expression, and rescues mechanical stress-induced cartilage degeneration. Wnt/ß-catenin signaling and SFRPs may represent potential therapeutic targets for TMJOA.

Submental Ultrasound Is Effective in Predicting Difficult Mask Ventilation but Not in Difficult Laryngoscopy.

The goal of this study was to determine the utility of submental ultrasound parameters in distinguishing difficult airway management from easy airway management. Forty-one adult patients who underwent elective surgery under general anesthesia with endotracheal intubation from March to December 2018 were included. We used submental ultrasound to measure tongue base thickness (TBT) in the midsagittal plane and the distance between lingual arteries (DLA) in the transverse dimension. The primary outcome was difficult laryngoscopy, and the secondary outcome was difficult mask ventilation. Receiver operating characteristic curve analysis and logistic regression revealed no correlation between difficult laryngoscopy and SMUS measurements. Nevertheless, patients with difficult mask ventilation had significantly higher TBT (p = 0.009) and longer DLA (p = 0.010). After adjustment of confounding factors, increased TBT (>69.6 mm) was the sole independent predictor of difficult mask ventilation. The results indicated that SMUS is effective in predicting difficult mask ventilation but not difficult laryngoscopy.