Search Results (626)

Background and Objectives: The most popular surgical procedures among orthognathic surgeries for Class II and III patients are Le Fort 1 osteotomy for the maxilla and bilateral sagittal split ramus osteotomy (BSSRO) for the mandible. Keeping the condyle in its proper place during fixation is one of the difficulties of orthognathic surgery. One of the worst post-orthognathic surgery consequences in the temporomandibular joint (TMJ) area may be condylar resorption. Condylar remodeling refers to a group of processes that occur in reaction to forces and stress placed on the temporomandibular joint in order to preserve morphological, functional, and occlusal balance. A systematic review of the literature was performed with the aim of identifying the mandibular condylar component of TMJ changes after orthognathic surgery in class II and III patients. Materials and Methods: An electronic search was carried out using the PubMed, Cochrane Library, and Google Scholar, databases. The inclusion criteria included trials in non-growing patients upon whom orthognathic surgery was performed due to Angle II or Angle III classes malocclusion; in addition, a CT or cone beam computed tomography (CBCT) scan was performed before and after surgery to track the mandibular condylar component of TMJ changes. The quality of the studies was evaluated by two independent authors. The risk of bias was assessed by using the Downs and Black checklist. Results: The electronic and manual literature search yielded 12 studies that fulfilled all necessary inclusion criteria. Observed studies were evaluated as good (3), fair (8), and poor (1) quality. Two studies evaluated class II patients, six studies observed class III patients, and four studies were comparative. Most of the studies evaluated condyle angle and space changes, and the condylar surface and volume changes were also observed. However, the methodology of evaluation in the publications differs. Conclusions: Reduction of bone density, especially in class II patients, and morphological condyle reshaping, with the apposition of the bone, is the main adaptive mechanism after orthognathic surgery. However, all of the studies we examined were conducted using different methods of evaluation, measurement, and reference points. Full article

Background and Objectives: With the goal of identifying regions with bicortical bone and avoiding root contact, the present study proposes an innovative technique for the simulation of the insertion of mini orthodontic implants using automatic jaw segmentation. The simulation of mini implants takes place in 3D rendering visualization instead of Multi-Planar Reconstruction (MPR) sections. Materials and Methods: The procedure involves utilizing software that automatically segments the jaw, teeth, and implants, ensuring their visibility in 3D rendering images. These segmented files are utilized as study models to determine the optimum location for simulating orthodontic implants, in particular locations characterized by limited distances between the implant and the roots, as well as locations where the bicortical structures are present. Results: By using this method, we were able to simulate the insertion of mini implants in the maxilla by applying two cumulative requirements: the implant tip needs to be positioned in a bicortical area, and it needs to be situated more than 0.6 mm away from the neighboring teeth’s roots along all of their axes. Additionally, it is possible to replicate the positioning of the mini implant in order to distalize the molars in the mandible while avoiding the mandibular canal and the path of molar migration. Conclusions: The utilization of automated segmentation and visualization techniques in 3D rendering enhances safety measures during the simulation and insertion of orthodontic mini implants, increasing the insertion precision and providing an advantage in the identification of bicortical structures, increasing their stability. Full article

(1) Background: In recent years, there has been a growing interest in tooth-derived materials as valuable alternatives to synthetic biomaterials for preventing alveolar ridge dimensional changes. This study aimed to evaluate the histological and clinical differences between alveolar ridge preservation procedures in the maxilla and mandible using demineralized dentin treated with Tooth Transformer^®. (2) Methods: A total of 178 patients in good general health were enrolled, with 187 post-extractive sockets lacking buccal and/or palatal bone walls. Alveolar socket preservation procedures and histological evaluations were performed. The sites were divided into two groups: Group A (99 mandibular samples) and Group B (108 maxillary samples). After 5 months (±1 month), single bone biopsies were performed for histologic and histomorphometric analysis. (3) Results: Clinical outcomes demonstrated a good healing of hard and soft tissues with an effective maintenance of bone architecture in both groups. Histomorphometric analysis revealed a total bone volume of 50.33% (±14.86) in Group A compared to 43.53% (±12.73) in Group B. The vital new bone volume was 40.59% (±19.90) in Group A versus 29.70% (±17.68) in Group B, with residual graft dentin material volume at 7.95% (±9.85) in Group A compared to 6.75% (±9.62) in Group B. (4) Conclusions: These results indicate that tooth-derived material supports hard tissue reconstruction by following the structure of the surrounding bone tissue. A 6.8% difference observed between the maxilla and mandible reflects the inherent disparities in natural bone structures in these regions. This suggests that the bone regeneration process after tooth extraction adheres to an anatomical functional pattern that reflects the specific bone characteristics of each area, thus contributing to the preservation of the morphology and functionality of the surrounding bone tissue. Full article

Objectives: To assess the impact of the presence or position (buccal/palatal) of impacted canines on trabecular bone density using fractal analysis (FA) on cone-beam computed tomography (CBCT) images, and to compare the results with a control group without impacted canines. Methods: This retrospective study included 41 patients with unilateral impacted canines (30 palatal, 11 buccal) and a control group of 39 patients who underwent surgically assisted rapid maxillary expansion. All patients had CBCT images recorded for diagnostic and treatment purposes. Cross-sectional CBCT images were obtained between the first and second premolars on both sides of the patients’ maxilla. From these images, fractal dimension (FD) was measured in a 20 × 20 pixel region of interest in the trabecular bone using the ImageJ software. Results: The FD values were significantly higher on the impacted side in the impacted canine group (p = 0.02). Within the impacted canine group, a significant increase in FD was observed on the impacted side in the buccal-impacted subgroup (p = 0.02), while no significant difference was observed in the palatal-impacted subgroup (p > 0.05). Conclusions: According to the results of our study, there is an association between the position of the impacted canine and trabecular bone density. An increased trabecular bone density may play a role in the etiology of buccally impacted canines. Clinicians should consider anchorage planning, and appropriate force level, during the forced eruption of buccally impacted canines with high surrounding bone density, to minimize undesirable movements and achieve optimal treatment outcomes. Full article

Objective: This study investigated how the number of images collected for digital measurements in dentistry affects accuracy compared with traditional methods. Methods: A Frasaco maxillary model was scanned using a SHINING 3D AutoScan-DS-MIX dental 3D scanner to create an STL file. The maxilla was molded 10 times using polyvinyl siloxane (Zhermack Elite HD+) to produce plaster models, which were scanned with the same reference scanner to generate 10 STL files. The Frasaco model was scanned 10 times, capturing images in intervals of 800–1000, 1000–1200, and 1200–1500 using a 3Shape TRIOS 3 intraoral scanner, creating additional STL files. These were analyzed with reverse engineering software. Results: The most accurate measurements were obtained using 1200–1500 images. Conventional impression techniques performed significantly worse. There was a significant difference between the groups Digital 1200–1500 and Plaster (p < 0.001) and between Digital 800–1000 and Plaster (p = 0.007). No significant difference was found when the digital groups were compared among themselves. There was also no significant difference between the Plaster and Digital 1000–1200 groups. To compare precision values that were normally distributed across three or more methods, a one-way ANOVA was used. Trueness values that were not normally distributed with three or more methods were compared employing the Kruskal–Wallis test. Conclusions: Different image counts affect digital measurement accuracy. The most accurate measurements were obtained when collecting 1200–1500 images. Conventional impression techniques were shown to perform significantly worse than digital impression. Full article

Background/Objectives: Dental implants have emerged as a modern solution for edentulous jaws, showing high success rates. However, the implant’s success often hinges on the patient’s bone quality and quantity, leading to higher failure rates in poor bone sites. To address this issue, short implants have become a viable alternative to traditional approaches like bone sinus lifting. Among these, Bicon^® short implants with a plateau design are popular for their increased surface area, offering potential advantages over threaded implants. Despite their promise, the variability in patient-specific bone quality remains a critical factor influencing implant success and bone turnover regulated by bone strains. Excessive strains can lead to bone loss and implant failure according to Frost’s “Mechanostat” theory. To better understand the implant biomechanical environment, numerical simulation (FEA) is invaluable for correlating implant and bone parameters with strain fields in adjacent bone. The goal was to establish key relationships between short implant geometry, bone quality and quantity, and strain levels in the adjacent bone of patient-dependent elasticity to mitigate the risk of implant failure by avoiding pathological strains. Methods: Nine Bicon Integra-CP™ implants were chosen. Using CT scans, three-dimensional models of the posterior maxilla were created in Solidworks 2022 software to represent the most challenging scenario with minimal available bone, and the implant models were positioned in the jaw with the implant apex supported by the sinus cortical bone. Outer dimensions of the maxilla segment models were determined based on a prior convergence test. Implants and abutments were considered as a single unit made of titanium alloy. The bone segments simulated types III/IV bone by different cancellous bone elasticities and by variable cortical bone elasticity moduli selected based on an experimental data range. Both implants and bone were treated as linearly elastic and isotropic materials. Boundary conditions were restraining the disto-mesial and cranial surfaces of the bone segments. The bone–implant assemblies were subjected to oblique loads, and the bone’s first principal strain fields were analyzed. Maximum strain values were compared with the “minimum effective strain pathological” threshold of 3000 microstrain to assess the implant prognosis. Results: Physiological strains ranging from 490 to 3000 microstrain were observed in the crestal cortical bone, with no excessive strains detected at the implant neck area across different implant dimensions and cortical bone elasticity. In cancellous bone, maximum strains were observed at the first fin tip and were influenced by the implant diameter and length, as well as bone quality and cortical bone elasticity. In the spectrum of modeled bone elasticity and implant dimensions, increasing implant diameter from 4.5 to 6.0 mm resulted in a reduction in maximum strains by 34% to 52%, depending on bone type and cortical bone elasticity. Similarly, increasing implant length from 5.0 to 8.0 mm led to a reduction in maximum strains by 15% to 37%. Additionally, a two-fold reduction in cancellous bone elasticity modulus (type IV vs. III) corresponded to an increase in maximum strains by 16% to 59%. Also, maximum strains increased by 86% to 129% due to a decrease in patient-dependent cortical bone elasticity from the softest to the most rigid bone. Conclusions: The findings have practical implications for dental practitioners planning short finned implants in the posterior maxilla. In cases where the quality of cortical bone is uncertain and bone height is insufficient, wider 6.0 mm diameter implants should be preferred to mitigate the risk of pathological strains. Further investigations of cortical bone architecture and elasticity in the posterior maxilla are recommended to develop comprehensive clinical recommendations considering bone volume and quality limitations. Such research can potentially enable the placement of narrower implants in cases of insufficient bone. Full article

Background and Objectives: The aim of this study was to clinically evaluate the primary and secondary stability of dental implants with different macrodesigns using resonance frequency analysis and to determine whether implant design and length influence implant stability. Materials and methods: This study included 48 healthy patients receiving dental implants, and a pre-implant planning protocol was used, which involved detailed bone analysis, clinical examinations, and Cone beam computed tomography (CBCT) analysis. The implants were of various types and dimensions (Alpha-Bio Tec (Israel), DFI, SPI, and NEO), and the surgical procedures were performed using standard methods. Implant stability was measured using resonance frequency analysis (RFA) immediately after placement and after 3, 6, and 12 months. The total number of implants placed in all patients was 96. Results: The average primary stability value for 10 mm SPI implants placed in the maxilla was 68.2 ± 1.7 Implant Stability Quotient (ISQ) units, while for 10 mm NEO implants, it was 74.0 ± 0.9. The average primary stability value for a 10 mm DFI implant placed in the mandible was 72.8 ± 1.2 ISQ, while for a 10 mm NEO implant placed in the mandible, it was 76.3 ± 0.8 ISQ. Based on the Friedman ANOVA test, the differences in the stability measurements for the 10 mm and 11.5 mm SPI implants and for the 10 mm and 11.5 mm NEO implants in the maxilla on day 0 and after 3, 6, and 12 months were significant at p < 0.05. Similarly, based on the Friedman ANOVA test, the differences in the stability measurements for the 10 mm and 11.5 mm DFI implants and for the 10 mm and 11.5 mm NEO implants in the mandible on day 0 and after 3, 6, and 12 months were significant at p < 0.05 (p = 0.00000). Conclusions: Universal tapered implants of the NEO type stood out as the optimal choice, as they provided statistically significantly higher primary stability in both soft and hard bone types compared to other implants. The implant length did not significantly affect this stability. Full article

In this study, we aimed to investigate the differences in tissue surface adaptation and the variations in distances between reference points on the polished surfaces of 3D-printed denture bases produced at different build angles. The build angles were 0°, 30°, 60°, and 90°, with 15 denture bases printed for each angle. Using the Geomagic Control^® software, a 3D best-fit alignment was conducted between the denture base tissue surface and the reference shape of the edentulous maxilla model to calculate the root mean square error. The distances between reference points on the polished surface were measured using digital calipers. A one-way analysis of variance was conducted for statistical analysis. The adaptation, as measured by the root mean square error, varied significantly among denture bases with different build angles. The distances between the anterior and posterior reference points of the polished surface were also significantly different. However, within the limitations of this study, the variations in adaptations and dimensional accuracy across different build angles were within clinically acceptable ranges. In clinical practice, the print angle can be adjusted based on factors such as printing time, resin consumption, and the number of denture bases being printed simultaneously. Full article

During two expeditions to the seamounts in the Yap-Caroline area of the Western Pacific, a new genus, Phoxirostus gen. nov., in the family Laphystiopsidae Stebbing, 1899, is erected for two new species, P. longicarpus sp. nov. (type species) and P. yapensis sp. nov. The new genus can be distinguished from the other three laphystiopsid genera by the acute rostrum not overreaching the distal end of the first peduncular article of antenna 1, the outer plate of maxilla 1 bearing 10–11 spines, and the elongated carpus of pereopods 3–7 being distinctly longer than half the length of the propodus. Phoxirostus longicarpus sp. nov. differs from P. yapensis sp. nov. by the shape of the eyes and coxa 4, the presence of posterodistal protrusions on pleonite 1, and the number of posterodistal protrusions on pleonite 2. Generic analysis of one mitochondrial (COI) and one nuclear (H3) gene using maximum likelihood and Bayesian inference clarified the phylogenetic position of the Laphystiopsidae within the superfamily Iphimedioidea Boeck, 1871. Full article

Introduction and aim: Orthodontic treatment of impacted maxillary canines is challenging and expensive. This study investigated factors associated with impaction risk and the need for surgical exposure. Methods: Seventy-five participants of similar age, skeletal maturity, and gender (32 impacted canines, 43 controls) were included in the case-controlled trial. Three-dimensional study models were created (Trios 3, 3Shape), and panoramic radiographs were taken. The 3D digital models were measured using software to obtain morphological characteristics of the maxilla, such as maxillary surface area (mm²) and volume (mm³). Results: The impacted canine group displayed a significantly higher prevalence of deep bite (OR = 5.01), hypoplastic lateral incisors (OR = 5.47), and rotated adjacent teeth (OR = 3.56) compared to the control group. The impacted canine group exhibited a smaller maxillary surface area and volume. Within the impacted canine group, factors associated with a greater need for surgical exposure included the presence of a persistent deciduous canine (OR = 10.15), a palatal canine position (OR = 7.50), and a steeper canine angulation (p < 0.001). Conclusions: These findings suggest that several signs can serve as potential predictors of increased risk for maxillary canine impaction and the need for surgical intervention. Identifying these factors can aid in early diagnosis and treatment planning for improved patient outcomes. Full article

This study aimed to describe the changes produced on the occlusal plane (OP), the mandibular position and the dentoalveolar compensations of patients with distalization of the maxillary/mandibular arch assisted by mini-screws (MS). A descriptive case–series study was performed using the digital lateral cephalograms (DLC) of nine patients who underwent orthodontic treatment and required the use of MS for a complete distalization of the maxillary/mandibular arch. Records were collected at three different times (T1–T2–T3) and digitally analyzed (variables: Skeletal diagnosis; maxillary occlusal plane; position of the maxilla/mandible; and dentoalveolar changes of the distalization arch tracing the longitudinal axis of incisors/molars regarding the palatal/mandibular plane). Findings show that the OP varied from T1–T2–T3 in all cases, indicating its stepping or flattening. ODI, APDI, SNA, SNB, and ANB changed minimally in all cases, without variations in the mandibular position or in the skeletal diagnosis. Dentoalveolar measurements also showed differences between T1–T2–T3. In summary, conventional orthodontic treatment modified the OP during the first phase of treatment. Moreover, the distalization mechanics with MS changed the OP and produced dentoalveolar changes, mainly in the inclination of incisors and molars. Other measures considered in the study did not change substantially. Full article

Conventional complete dentures remain to be an important treatment for edentulous patients, especially those of low socioeconomic status. This study is a retrospective analysis that aims to elucidate influencing factors of post-insertion complications and patient satisfaction. Clinical records of 164 patients who received both maxillary and mandibular complete dentures at an Australian university teaching clinic were assessed and analysed. The parameters considered include reason for attendance, presenting clinical status, experience of operator, numbers of appointments for fabrication and adjustment, post-insertion complications and events, and patient satisfaction. The differences among selected attributes were analysed using a Mann–Whitney test, Chi-square test, or Kruskal–Wallis test where applicable, while the relationships between discrete variables were assessed by Kendall’s correlation. First, the number of appointments for fabrication differed significantly between female (6.8 ± 1.8) and male patients (6.2 ± 1.3; p = 0.025) and between student (6.7 ± 1.7) and professional operators (6.0 ± 1.1; p = 0.015). The number of appointments for adjustment was significantly associated with patient age (τ_b = 0.167, p = 0.003) and sharply declined after the first three months. Second, post-insertion pain was the most frequent complication, and it was significantly more associated with the mandible than the maxilla (χ² = 21.670, p = 0.000). Similarly, mandibular complete dentures were also significantly more associated with post-insertion reline than the maxillary (χ² = 8.804, p = 0.003). Lastly, patient satisfaction was significantly associated with patient attendance with old/worn dentures (χ² = 9.468, p = 0.002), as well as the absence of retention/stability issues (χ² = 41.712, p = 0.000), post-insertion reline (χ² = 29.300, p = 0.000), or denture replacement (χ² = 13.968, p = 0.000). Dissatisfied patients had a significantly higher age (70.9 ± 11.0 vs. 66.2 ± 12.6; p = 0.023) and number of appointments for adjustment (4.9 ± 3.5 vs. 3.1 ± 2.1; p = 0.001) than satisfied patients. In summary, these findings revealed the above factors that influence the fabrication process, post-insertion complication, and patient satisfaction of conventional complete dentures. Future research may include analysis of cases completed at private practices and consideration of other potentially relevant factors such as denture usage and mental status. Full article

The objective of this study is to present an uncommon case of adenomatoid odontogenic tumor (AOT) with an impacted maxillary canine, initially mimicking a follicular cyst. AOT is a rare odontogenic tumor, accounting for approximately 1% to 9% of all odontogenic tumors. It primarily occurs in the maxilla and is often associated with an unerupted permanent tooth. Follicular cysts, also known as dentigerous cysts, are benign odontogenic cysts that encase the crown of an unerupted or impacted tooth. We describe a case of AOT occurring in a 14-year-old male. Both the follicular cyst and adenomatoid odontogenic tumor (AOT) can exhibit similar clinical and radiographic presentations. It is crucial to accurately differentiate between the two to ensure appropriate treatment and prognosis. Full article

Odontogenic cysts are frequently encountered in clinical practice. However, residual cysts, a specific type of inflammatory odontogenic cyst, are relatively rare. These cysts may slowly expand over time, damaging surrounding soft tissues and bone, typically without posing a threat to life. We report the case of a 67-year-old man with liver failure and a cystic tumor in his right maxilla that had invaded his oral cavity and cheek, causing nasal obstruction and severe bleeding following an incisional biopsy. A computed tomography (CT) scan of the mass was nonspecific, and an initial histopathological analysis of the tissues was inconclusive due to chronic inflammation and hemorrhagic alterations, complicating the diagnostic pathway. The suspicion of a potentially aggressive malignant neoplasm and the need for immediate intervention due to bleeding necessitated a tracheotomy, tumor removal, percutaneous endoscopic gastrostomy, and transfusions of red blood cells. A subsequent histopathological examination revealed features indicative of a residual cyst. The entire lesion was excised through functional endoscopic sinus surgery. The surgical treatment was performed safely and effectively. Follow-up CT confirmed complete removal of the lesion. This case highlights a rare yet possible complication of odontogenic cysts and underscores the necessity of early diagnosis and comprehensive prophylaxis to prevent severe complications. Full article

Background: Metastatic tumors of the oro-facial tissuesare rare, with an incidence ranging between 1% and 8% of all oral malignant tumors. Generally reported with a peak of incidence in the 5–7th decades but possibly occurring at any age, metastases may represent the first sign of an occult cancer or manifest in patients with an already known history of a primary carcinoma, mostly from the lungs, kidney, prostate, and colon/rectum in males, and the uterus, breast, lung, and ovary in females. In the oro-facial tissues, the most involved sites are the oral mucosa, gingiva/jawbones, tongue, and salivary glands. Methods: A broad and deep literature review with a comprehensive analysis of the existing research on oro-facial metastases from renal-cell carcinoma (RCC) was conducted by searching the most used databases, with attention also paid to the clear-cell histological variant, which is the most frequent one. Results: Among the 156 analyzed studies, 206 cases of oro-facial metastases of renal cancer were found in patients with an average age of 60.9 years (145 males, 70.3%; 61 females, 29.6%). In almost 40% of the cases, metastasis represented the first clinical manifestation of the primary tumor, and 122 were histologically diagnosed as clear-cell renal-cell carcinoma (ccRCC) (59.2%). The tongue was involved in most of the cases (55 cases, 26.7%), followed by the gingiva (39 cases, 18.9%), mandible (35 cases, 16.9%), maxilla (23 cases, 11.1%), parotid gland (22 cases, 10.6%), buccal mucosa (11 cases, 5.3%), lips (7 cases, 3.3%), hard palate (6 cases, 2.8%), soft palate, masticatory space, and submandibular gland (2 cases, 0.9%), and lymph nodes, tonsils, and floor of the mouth (1 case, 0.4%). Among the 122 ccRCCs (84 males, 68.8%; 38 females, 31.1%), with an average age of 60.8 years and representing in 33.6% the first clinical manifestation, the tongue remained the most frequent site (31 cases, 25.4%), followed by the gingiva (21 cases, 17.2%), parotid gland (16 cases, 13.1%), mandibular bone (15 cases, 12.2%), maxillary bone (14 cases, 11.4%), buccal mucosa and lips (6 cases, 4.9%), hard palate (5 cases, 4%), submandibular gland and soft palate (2 cases, 1.6%), and lymph nodes, tonsils, oral floor, and masticatory space (1 case, 0.8%). The clinical presentation in soft tissues was mainly represented by a fast-growing exophytic mass, sometimes accompanied by pain, while in bone, it generally presented as radiolucent lesions with ill-defined borders and cortical erosion. Conclusions: The current comprehensive review collected data from the literature about the incidence, site of occurrence, age, sex, and survival of patients affected by oro-facial metastases from renal-cell carcinoma, with particular attention paid to the cases diagnosed as metastases from clear-cell renal-cell carcinoma, which is the most frequent histological variant. Clinical differential diagnosis is widely discussed to provide clinicians with all the useful information for an early diagnosis despite the effective difficulties in recognizing such rare and easily misdiagnosed lesionsTheir early identification represents a diagnostic challenge, especially when the clinical work-up is limited to the cervico–facial region. Nevertheless, early diagnosis and recently introduced adjuvant therapies may represent the key to better outcomes in such patients. Therefore, general guidelines about the clinical and radiological identification of oro-facial potentially malignant lesions should be part of the cultural background of any dentist. Full article