Mandibular Teeth Research Articles

Prospective case series study on the survival rates of occlusal polymethyl methacrylate veneers as a semipermanent therapy in patients with severe pathologic tooth wear.

To evaluate the survival rate of minimally invasive semipermanent occlusal polymethyl methacrylate (PMMA) onlays/veneers in previous temporomandibular disorder (TMD) patients with severe tooth wear and with a loss of vertical dimension after up to 7 years. This case series was designed as a follow-up evaluation with consecutive patient recruitment. All patients bearing the indication for this kind of rehabilitation were treated by the same clinician using the same adhesive methodology. The study included 22 patients (3 men/19 women), with a mean ± SD age of 50.7 ± 11.6 years. Controls followed within the first 4 weeks (and subsequently as required). Failure criteria included damage by fracture, chipping, and retention loss. Survival rates were determined based on the Kaplan-Meier analysis. 328 semipermanent occlusal/incisal veneers were included (142 maxillary/186 mandibular teeth). Almost 80% of the restorations were in place and in function when starting the follow-up treatment after 180 days; failures predominantly occurred within the first 3 to 6 months but proved reparable. Depending on the patients' priorities, scheduled replacements followed successively, and more than 65% did not show repair or any renewal needs for more than 360 days. Within the limitations of this study the survival rates of occlusal veneers made of PMMA were sufficiently high to allow for consecutive treatment of the respective teeth by means of permanent restorations while preserving the restored vertical dimension. In patients with severe tooth wear and a TMD history, semipermanent restorative therapy with occlusal PMMA onlays/veneers would seem a noteworthy option.

Class III correction and enhanced periodontal health with aligner treatment in a 53-year-old patient.

In this case report, we describe the successful camouflage treatment of a 53-year-old female with dental and skeletal Class III malocclusion combined with anterior crossbite, gingival recession, and mobility of the lower incisors, using clear aligners. The treatment involved periodontal debridement followed by orthodontic treatment. The mandibular posterior teeth were distalized to correct the anterior crossbite and to establish Class I molar relationships. During treatment, the mandibular incisors were intruded, and the mandibular occlusal plane underwent a clockwise rotation due to slight extrusion of the maxillary buccal segments and distalization of the mandibular posterior teeth. Following treatment, all objectives were achieved, including resolution of the anterior crossbite, significant reduction of gingival recession and tooth mobility, and improved functional occlusion. The dental and skeletal Class III malocclusion was corrected, and the marginal alveolar bone dehiscence was significantly reduced. The results remained stable over a 3-year retention period, with enhanced molar intercuspation and gingival growth progression. This case adds to the evidence supporting the adaptability and effectiveness of clear aligners in treating orthodontic patients with compromised periodontium. The treatment outcomes support that orthodontic treatment using clear aligners, combined with periodontal monitoring, can assist in managing alveolar bone defects, gingival recession, and tooth mobility.

The Role of Bone and Root Resorption on the Biomechanical Behavior of Mandibular Anterior Teeth Subjected to Orthodontic Forces: A Finite Element Approach.

This study was conducted to systematically evaluate the biomechanical impact of varying degrees of root and bone resorption resulting from periodontitis and orthodontic tooth movement (OTM) on the mandibular anterior teeth. The objective was to determine whether these distinct resorption patterns exert a specific influence on tooth displacement and strain patterns. A finite element (FE) model of an idealized anterior mandible from the first premolar in the third to the fourth quadrant was developed without bone or root resorption and a constant periodontal ligament (PDL) thickness of 0.2 mm. Variations included three root resorption levels (0%, 20%, 50%) and three bone resorption types (circular 50%, circular 80%, vestibular 80%). Models ranged from 200,000 to 440,000 elements and 55,000 to 130,000 nodes. Orthodontic forces, namely root torque (5 Nmm), intrusion (0.2 N), and distalization (0.5 N) were applied for subsequent crown displacement and PDL strain analysis. A total of 180 simulations were performed. Simulations showed that displacement was similar across different bone resorption conditions, irrespective of modeled root resorptions. Circumferential bone resorption increased tooth displacement, regardless of root resorption status. Vestibular bone resorption exhibited less increase in tooth displacement. However, when accompanied by root resorption, the combination exacerbated tooth displacement. Strains in the PDL clearly increased with a circumferential bone resorption of 80%. This study highlights the critical role of bone resorption in tooth displacement during OTM, particularly the challenges associated with circumferential resorption. Clinicians must consider both bone and root resorption for personalized medicine treatment of patients with severe periodontitis, in favor of low-force application strategies to optimize outcomes and minimize complications linked to excessive tooth displacement.

Prevalence of Middle Mesial Canal in Mandibular Molar Teeth Using CBCT

Introduction: Identification and completely cleaning the extra root canals are crucial for the success of endodontic treatment. Prevalence of the middle mesial canal (MMC) in mandibular molars is still a topic of debate due to the complex and diverse anatomy and morphology of these teeth. This study aimed to investigate the prevalence of MMC in mandibular molars using CBCT radiography. Methods: In this descriptive cross-sectional study, 300 CBCT images obtained between 1995 and 2019 in a private oral and maxillofacial radiology center in Yazd, Iran, were evaluated. The first and second mandibular molars were examined for the presence of MMC based on the patients' age, gender, tooth location, and type. Data were analyzed using SPSS 17 and the Chi-square. Results: Out of 300 mandibular molars (122 first molars and 178 second molars), MMC was found in only 18 teeth (6%). The prevalence of MMC was significantly higher in the first molars (18 cases) than in the second molars (0 cases). Twelve MMCs were observed in females and 6 in males. 12 MMCs were located in the left side and the rest in the right side. The mean age of individuals with MMC was 37.33±15.27. There was no statistically significant association between the presence of MMC and age, gender, or tooth location (P > 0.05), but the prevalence of MMC was higher in the first molars than in the second molars (P = 0.0001). Conclusion: The prevalence of MMC in mandibular first molars was low in the studied population and was not detected in mandibular second molars. Nevertheless, the possibility of MMC should be considered during the treatment of teeth.

Euler-angle norms for tooth rotation, torque and tip.

The aim of the current study was to develop and describe a new measuring system for the orientation of a tooth in a digitalized cast of a jaw and provide new angular values for the rotation, torque and tip of maxillary and mandibular teeth. This retrospective cross-sectional study involved the utilization of a sub-group of extrinsic Euler-angles to derive optimal norm values per tooth in three different planes of orientation ('rotation', 'torque' and 'tip') by evaluating the digital representations of the teeth derived from a database containing over 17,500 patients. The process involved the entry of the .stl files of the jaw pairs into a fully automated software system (Smyl:Ai, Ulm, Germany) whereupon jaw alignment, teeth segmentation, landmark identification and visual validation of input files was conducted prior to calculation of the norm values for the three different planes of orientation. The digital scans in stereolithography (.STL)-file format of the upper and lower dentitions of 1914 individuals with optimal occlusion were chosen and evaluated. New mean (standard deviation) angular values were determined for the rotation, torque and tip of maxillary and mandibular teeth. The findings facilitate the reappraisal of rotation, torque and tip values currently acceptable as ideal. They will inform anthropologists and dental researchers about occlusion and alignment in orthodontic and non-orthodontic patients and provide baseline data for future studies. The methodology will also enable the evaluation of large numbers of data in relatively short timeframes.

Evaluation of mandibular trabecular bone by fractal analysis in pediatric patients with hypodontia of the mandibular second premolar tooth

BackgroundIt is still unclear whether the trabecular structure of the jaw is different in individuals with hypodontia than in those without hypodontia; this is important for clinicians. The aim was to determine whether the mandibular trabecular bone structure of children and adolescents with hypodontia differs from the control group by using the fractal analysis (FA) method in this study.MethodsA total of 138 panoramic radiographs of 69 cases and 69 control subjects (mean age 13.2 ± 10.1) were evaluated. The age and gender of subjects in the case and control groups were matched. Three regions of interest (ROIs) were selected from the panoramic radiographs. ROI1 refers to the center of the ramus rising above the mandibular foramen. ROI2 refers to the area between the apical level of the mandibular molar and the upper border of the mandibular canal. ROI3, the missing tooth region, refers to the apical third of the mesial side of the erupting or fully erupted permanent mandibular first molar. Mann-Whitney U and Wilcoxon tests were used. p < 0.05 was accepted for the significance value.ResultsThe mean fractal dimension (FD) values of ROI1, ROI2, and ROI3 were 1,25, 1,20, and 1,13, respectively. The means FD values obtained from the ramus region were higher than the other regions (p < 0.05). The FD values did not differ significantly according to gender and age (p > 0.05). The FD values of the case group were lower than the control group for ROI3 (p < 0.05).ConclusionThe results of this study showed that the mandibular trabecular bone quality of pediatric patients with one missing tooth was different from the healthy group. The difference in the mean FD values from the ROIs indicates that the ramus has a denser structure than the mandibular corpus. Clinicians should factor this into their dental treatment planning process.

Quantitative statistical evaluation of maxillary and mandibular incisor root canal morphology in Saudi patients

Abstract Introduction: Clinical practice demands understanding the complexity of the root canal system to achieve desired treatment goals. The statistically detailed morphology of the tooth and root canal morphology is very important to know. Therefore, the present study aims to investigate the statistical analysis of root canal morphology and morphological variations of maxillary and mandibular incisor teeth using cone-beam computed tomography (CBCT) in Saudi patients attending King Saud University Dental Hospital. Materials and Methods: CBCT images of 480 patients were selected. Number of roots and root canal configuration were identified and categorized according to Vertucci’s classification. Tooth length, distance from cementoenamel junction (CEJ) to the area of canal division, and width of the canal at the area of division were also evaluated. Bilateral symmetry and association between gender and age with the different variables were investigated. Data were analyzed using Chi-square, multiple linear regression, and McNemar’s tests. Results: A total of 3412 teeth were evaluated. All maxillary teeth had one root with Type I canal configuration. For mandibular teeth, all exhibited one root with the majority having Type I canal configuration in central (71.2%) and lateral (75%) incisor teeth. There was a statistically significant association between number of canals and age in mandibular incisor teeth observed only in females (P &lt; 0.001), while no association was observed between canal configuration and gender (P = 0.900 and P = 0.721, respectively). Multiple regression analyses showed that age and gender significantly explain the difference of the variance in tooth length (P &lt; 0.001). Moreover, bilateral symmetry was observed in 98.1% of mandibular central and 97.6% of lateral incisor teeth with no statistically significant association (P = 1 and P = 0.058, respectively). Conclusion: All maxillary and most mandibular incisor teeth present with one root and Type I canal configuration. In general, males have longer teeth than females, with a significant decrease in length with each year increase in age. Mandibular lateral incisor teeth exhibited the highest mean distance from CEJ to point of canal separation and highest mean width in the area of canal division.

Evaluation of the forces applied by rubber dam clamps on mandibular first molar teeth with different endodontic access cavities: a 3D FEA study.

This study aimed to examine the effect of the force applied by rubber dam clamps made from different materials on mandibular first molar teeth with various designs of endodontic access cavities using finite element analysis. A intact tooth (IT) and seven different endodontic access cavities namely, a traditional endodontic cavity (TRADAC), a guided endodontic cavity (GEC), a conservative endodontic cavity (CAC), an ultra-conservative access cavity (UAC), a truss access endodontic cavity (TRSAC), a mesial caries access cavity (MCAC), and a distal caries access cavity (DCAC), along with two different clamp finite element models, were created. The clamp models were made of polyether ether ketone (PEEK) and stainless steel (SS). The forces applied by the clamps were calculated based on the axial section distance of the tooth, and these forces were applied to the contact areas on the tooth. Stress distribution models were calculated using maximum von Mises (vM) stress. The lowest vM stress under the forces applied by the SS and PEEK clamps was found in the IT model (80.914 MPa) with the PEEK clamp. The highest vM stress was found in the DCAC model (759.49 MPa) applied with the SS clamp. The forces applied by SS clamps resulted in higher vM stress values in every cavity design than those applied by PEEK clamps. PEEK clamps generated less force than SS clamps. However, clinicians should follow various isolation strategies (clamp made of different materials, split dam, etc.) according to different cavity types of the tooth.

Combined endodontic and regenerative periodontal therapy for managing questionable mandibular anterior teeth with radicular cysts

Abstract Endodontic microsurgery (EMS) presents a great treatment option for unresolved periradicular pathologies, typically involving the removal of the apical root portion and adjacent inflamed tissues. This case report describes the management of persistent periapical lesions in the lower anterior teeth of a 32-year-old male. Root canal treatment was completed 4 years before presentation. The patient presented to the clinic with tooth mobility and mild discomfort and large radiographical periapical radiolucency. The case was diagnosed with previously treated with asymptomatic apical periodontitis. EMS was performed in conjunction with periodontal-guided tissue regeneration that includes bone graft and resorbable membrane and the teeth showed favorable resolution of the symptoms. Histopathological analysis showed the presence of a radicular cyst. After 3 years of follow-up, cone-beam computed tomography and periapical radiographs demonstrated substantial lesion regression and favorable outcome. This case report offering promising insights into the synergistic potential of combined endodontic and regenerative periodontal therapy in cases with unresolved periapical lesion with extensive bone destruction.

A case of early childhood caries from a Medieval site in Southern Portugal: a multidisciplinary approach.

Dental caries is the most prevalent chronic infectious disease during childhood both in historical and contemporary times, but research focused on the oral health of non-adults from the past is still scant. As such, this study proposes a multidisciplinary approach to the differential diagnosis of severe dental lesions in a medieval non-adult skeleton. The skeleton of a three-year-old child recovered in the medieval necropolis of Cacela Velha (Portugal) was studied through macroscopic, radiological, elemental and stable isotope analyses. This individual exhibited enamel destruction and dentine exposure in both the maxillary and mandibular teeth, with the latter also showing changes in coloration. Elemental analysis showed that his skull presented lower values of Si, Cl, and Ca and higher of Cu compared to the control, while the concentration of P and S were significantly lower in the teeth. Early childhood caries is the most probable diagnosis for the dental lesions observed, apparently stemming from a reticulate of factors that include potential malnutrition, and the consumption of sugars in complementary feeding - even though historical sources point to the scarcity of sugar in Portugal during most of the Middle Ages.

Chitosan nanoparticles, Rose Bengal-chitosan activated photodynamic therapy as final irrigant on pushout bond strength, smear layer removal efficacy and antibacterial effectiveness against E.faecalis

AimImpact of final root canal disinfectants diode laser (DL), Rose Bengal photosensitizer (RBP), Chitosan Nanoparticles (CNPs), and CNPs modified RBP on Enterococcus faecalis (E.faecalis) survival rate, smear layer (SL) removal efficacy and push out bond strength (PBS) of resin sealer to the radicular dentin. Material and methodSingle rooted seventy-five human mandibular premolar teeth were sectioned at a level of cementoenamel (CEJ) and root canal treatment was performed using a ProTaper rotary instrument. To assess the antibacterial efficiency E.faecalis inoculation was performed using a pour plate method. The samples were arbitrarily allocated into five groups based on the final disinfectant received (n = 15) Group-1 (NaOCl+17 % EDTA), Group-2 (NaOCl+DL), Group-3 (NaOCl+CNPs), Group-4 (NaOCl+RBP activated by DL) and Group-5 (NaOCl+CNPs-RBP activated by DL). SEM analysis for SL removal was performed on five specimens from each group. Root canal obturation and sectioning were performed at cervical, middle, and apical levels. PBS and failure mode were analyzed using a universal testing machine (UTM) and stereomicroscope respectively. The data was subjected to analysis using one-way analysis of variance (ANOVA) and Tukey's post hoc test. ResultGroup 1 (NaOCl+17 % EDTA) (0.36 ± 0.01 CFU/mL) unveiled the maximum survival rate of tested bacteria. However, Group 5 (NaOCl+CNPs-RBP activated by DL) (0.11 ± 0.01 CFU/mL) displayed minimum survival of E.faecalis. The highest SL removal (1.44 ± 0.11) and bond integrity scores (12.23 ± 0.24 MPa) were recorded in the coronal section of Group 5 (NaOCl+ CNPs-RBP activated by DL) treated roots. However, the lowest removal of SL (3.15 ± 1.09) and PBS (7.24 ± 0.09 MPa) were recorded in Group 4 (NaOCl+RBP activated by DL) treated canals. CONCLUSIONCNPs-RBP activated by DL as the final irrigant provided satisfactory antibacterial activity, SL removal, and bond strength outcomes compared to other tested groups.

Comparison of Mineral Density of Dental Structures of Ancient Human Skeletons from the Roman Period with Modern-Day Human Dental Structures

Comparison of maxillary, mandibular, dental crown and root mineral density in human skeletons identified in historical excavations with today's human maxillary, mandibular dental crown and root. After the skull images were obtained, four groups were created: maxilla 1, mandible 1 from the old period, maxilla 2 from the images taken from today's patients, and mandible 2 from the images taken from today's patients. Seventeen skeletons were previously classified as young age, middle age, and older age. Among the archive tomography images, 17 images from young (15-35), middle (36-56) and older (57 and over) age images were included in the study. HU value of the desired region was calculated automatically by the device using Region of interest (ROI). In this study, 34 jaws and 68 teeth were evaluated, including 7 mandibles and 10 maxillae from the late Roman period, and 8 mandibles and 9 maxillae from today's people. The average HU value of the crowns of mandibular anterior teeth from the late Roman period was measured as 2406.0. The average HU value of the crowns of maxillary anterior teeth was found to be 3383.8. In the posterior aspect, the average crown HU value measured in the maxilla was found to be higher than that in the mandible. The finding showed that the density of dental tissues of ancient people, such as enamel and dentin forming the crown, and cementum and dentin forming the root, was significantly higher than today's people.

Navigating the maze: A comprehensive journey in the management of odontogenic Keratocyst

This case report describes the intricate management of an odontogenic keratocyst (OKC) associated with a mandibular tooth. Formerly known as keratocystic odontogenic tumor, OKC is a benign intraosseous lesion with diverse manifestations that occurs either as a solitary entity or as multiple lesions within the same individual. Often linked to nevoid basal cell carcinoma syndrome (NBCCS), OKC presents a unique challenge requiring meticulous diagnosis and treatment. In this case, a 71-year-old male with significant mandibular swelling sought treatment after a failed endodontic procedure. Detailed clinical and radiographic evaluations revealed an extensive radiolucent lesion affecting teeth 45 to 36. The treatment involved a multidisciplinary approach, including endodontic therapy and surgical enucleation with bone curettage. The patient exhibited successful healing and bone formation during a one-year follow-up, emphasizing the significance of comprehensive management strategies for OKCs. This case underscores the importance of early diagnosis, collaboration between specialties, and long-term follow-up in ensuring optimal outcomes for patients with OKCs associated with mandibular teeth.

Evaluation and comparison of autologous particulate dentin with demineralized freeze dried bone allograft in ridge preservation procedures - a prospective clinical study.

To compare effectiveness of Autologous Particulate Dentin (APD) with Demineralized Freeze-Dried Bone Allograft (DFDBA) in ridge preservation, using radiographic and clinical parameters. Thirty subjects with indication of mandibular posterior teeth extraction were randomly assigned to either test or control group. After atraumatic extraction, ridge preservation was performed using APD or DFDBA mixed with i-PRF in test and control groups respectively. Both groups had sockets sealed with A-PRF membrane. Clinical parameters (plaque, gingival and healing indices) and radiographic parameters (vertical ridge height, horizontal ridge width) were assessed at baseline and 6 months using CBCT. Statistical analysis was performed using an independent t-test to compare clinical and radiographic parameters between the groups. Both groups had significant decreases in ridge dimensions over 6 months (p < 0.001). The test group showed less reduction in ridge dimensions than control group at 6 months (p < 0.001). Mean change in vertical height was not significant (1.37 ± 1.32, 1.7311 ± 0.563), but in horizontal ridge width (1.3120 ± 1.13, 1.8093 ± 1.16) was significantly different between test and control groups respectively. There was no statistical difference in clinical parameters between the groups at 6 months (p > 0.001). APD grafts resulted in significant improvements in radiographic parameters, specifically in vertical ridge height and horizontal ridge width, compared to DFDBA group. Autologous particulate dentin is a promising, versatile substitute for regenerative procedures. While more research on its long-term efficacy and application is needed, current evidence suggests it could significantly improve patient care and outcomes.

Mineral trioxide aggregate obturation quality with two obturation techniques in severe curved root canals – a micro-CT study

BackgroundThe existence of voids within the mineral trioxide aggregate (MTA) composition is one of the factors that can influence the treatment outcome. The primary objective of this study was to quantitatively assess and compare the MTA orthograde obturation quality in severe curved root canals using two different MTA compaction techniques: manual compaction with K-file, or Auger technique using micro-computed tomography (micro-CT) imaging.MethodsFor this study, 26 mandibular first molar teeth with severely curved mesiobuccal root canals were selected. These samples were randomly divided into two groups. All root canals were instrumented using ProTaper Gold rotary files up to the F3 file at the working length. In one group, OrthoMTA was compacted using a stainless steel K-file, while in the other group, the Auger technique was employed for compaction into the root canals. Once the MTA had completely set, the filled root canals were subjected to scanning using a high-resolution micro-CT scanner. The porosity volume was determined as a percentage in relation to the overal volume of the canal, and the collected data were subjected to analysis using SPSS software, with the significance level set at P < 0.05.ResultsThe two techniques had no significant difference in open, closed, and total mean porosity. In both groups, the mean of open porosity was significantly more than closed porosity.ConclusionsAccording to the results of the present study, neither of these two techniques is preferred to the other, and factors such as working time, etc., can be considered to choose the more appropriate clinical technique.

Critical Factors Affecting Outcomes of Endodontic Microsurgery: A Retrospective Japanese Study.

The critically important preoperative and intraoperative factors that affect the success of endodontic microsurgery (EMS) in Japanese patients are not defined. We conducted a retrospective study that analyzed treatment outcomes for 46 teeth in 46 Japanese patients. Treatment was provided between March 2013 and March 2015. All patients were evaluated after one year, the shortest time period over which treatment outcomes after apicoectomy could be evaluated and in which there were complete records for the recruited patient population. Healing was assessed on the basis of clinical symptoms and radiographs. With the use of a binary logistic regression model to quantify success, we estimated the effects of patient age, sex, dental arch, lesion size, lesion type, preoperative root canal treatment, the presence or absence of a post core, and the presence or absence of an isthmus on the surgically prepared dentine surface. The overall success for EMS was 93.5% after one year; failures comprised 6.5%. Successful outcomes were higher (p = 0.04) for maxillary teeth than for mandibular teeth. Success was higher (p = 0.019) for patients who received root canal instrumentation prior to EMS. Age, sex, lesion size, lesion type, the presence or absence of a post core, and the presence or absence of a root canal isthmus had no effect (p > 0.2) on success. We conclude that the percentage of successful outcomes after EMS treatment for Japanese patients presenting with periapical periodontitis is very high after one year and that success is influenced strongly by the dental arch and preoperative root canal instrumentation.

Anterior Hyperfunction Syndrome: Literature Review and Conceptual Model.

Combined Kelly syndrome, also known as anterior hyperfunction syndrome, is a complex pathological condition of the stomatognathic system, originally established by five characteristics but primarily triggered by edentulism, specifically, the absence of the upper and posterior mandibular teeth. This condition is characterized by a series of clinical features, such as bone loss, tuberosity growth, enamel wear, periodontal damage, muscle fatigue, pain, and temporomandibular joint issues. However, these features are not unique and rather reflect an oral hyperfunction state. There is a lack of consensus on the best way to assess and diagnose this condition, which is proposed to be understood as an "oral hyperfunction state" rather than a syndrome. This study aims to conduct a literature review to analyze the available information on anterior hyperfunction syndrome in dentistry, with the goal of proposing a conceptual model of the etiological risk factors that contribute to early diagnosis and the prevention of complications. This approach has important clinical implications, as it would allow for the early identification and management of risk factors, thus improving the quality of life of patients and preventing malpractice that could compromise their oral health.

The Impact of the Chlorhexidine Gel (WISDOM®) on Postoperative Sequelae Associated with the Surgical Removal of Impacted Mandibular Third Molars: A Randomized Controlled Clinical Trial

Background: One of the most prevalent procedures in oral surgery is the removal of impacted mandibular third molars, typically accompanied by trismus, edema, and pain. Several methods and biomaterials were implemented to mitigate or avoid these surgical problems. Objectives: To evaluate the efficiency of chlorhexidine gel (WISDOM®) in minimizing postoperative sequelae associated with the impacted mandibular third molar that will be surgically extracted and its role in promoting early soft tissue closure of the surgical site. Methods: The study design was a double-masked and randomized, controlled clinical study that included healthy patients needing the removal of a mandibular third molar through surgery. The participants were randomly assigned to two groups. The extraction site of the study group was filled with a mixture of gel foam and WISDOM®. In contrast, we filled the extraction sites of the control group patients with gel foam and sutured the surgical sites for both groups. The patients were evaluated on the first, third, and seventh postoperative days for pain, swelling, trismus, and early soft tissue healing. Results: Sixty eligible patients were enrolled in this study. The study group exhibited a statistically significant decrease in pain, edema, trismus, and early soft tissue healing on the first, third, and seventh postoperative days compared to the control group. Conclusions: WISDOM® gel can effectively reduce postoperative pain, trismus, and swelling and promote early soft tissue healing after surgical removal of an impacted mandibular wisdom tooth.

How accurate is predicted root movement achieved in four first-premolar extraction cases with Invisalign?

This study aims to compare the achieved and predicted root movements in adults after four first-premolar extractions and Invisalign treatment. Thirty-three consecutive adults (22 Class I, 9 Cusp-to-cusp Class II and 2 Cusp-to-cusp Class III) from a single clinical division who completed the first series of aligners after premolar extractions were included in this retrospective study. A pretreatment cone-beam computed tomography model was registered onto the pretreatment surface-scanned dental model (SSDM) to locate the pretreatment root apices of the whole dentition. These were copied and transferred to the predicted and achieved post-treatment SSDMs to acquire the locations of the predicted and achieved post-treatment root apices. The differences between predicted and achieved root movements (DPARMs) were tested using the paired t-test or Wilcoxon signed rank test. In the anteroposterior direction, posterior root movements of maxillary and mandibular anterior teeth were poorly achieved (3.24-5.74 mm DPARMs, p < .05). In the vertical direction, roots of maxillary anterior teeth achieved greater intrusion (0.70-0.93 mm DPARMs, p < .05), while those of mandibular incisors achieved less intrusion (0.57-0.65 mm DPARMs, p < .05) than predicted. In the mediolateral direction, lateral incisor roots did not move distally (-0.65 to -0.96 mm DPARMs, p < .05), while those of canines did not move buccally, compared with the prediction (-0.75 mm DPARMs, p < .05). In the four first-premolar extraction treatments with Invisalign, root movements were not achieved as predicted, particularly for anterior teeth in the anteroposterior direction.

The impact of mandibular partial edentulous distal extension on virtual occlusal record accuracy when using two different intraoral scanners: An in vitro analysis

ObjectivesThis in vitro study was formulated to clarify how mandibular partial edentulous distal extension involving three missing teeth affects the virtual occlusal record (VOR) accuracy, in terms of both trueness and precision, when using two different intraoral scanners (IOSs) – the Primescan (PS) and Trios 4 (TR) scanners. MethodsA typodont model missing the left mandibular second premolar, first molar, and second molar as well as the right mandibular first molar was mounted on a semi-adjustable articulator. Four implants were placed at the sites of the missing mandibular teeth. Six pairs of stainless steel markers (diameter: 0.5 mm) were affixed to the maxillary and mandibular casts in the buccal gingiva adjacent to the implants and on the facial surfaces of teeth as reference positions for measurements. The model was digitized with an inEox X5 laboratory scanner to create a reference dataset. Intraoral scans were performed with the PS and TR scanners, with each scan duplicated 10 times to generate 20 paired IOS files. Automatic VOR generation followed the bilateral buccal scan protocol, divided into PS and TR groups (n = 10). Six subgroups of linear distances between interarch markers were assessed with Geomagic Control software, comparing deviations from the reference scan. Data normality was confirmed with the Shapiro-Wilk test. Trueness was evaluated with two-way ANOVAs and pairwise comparisons performed with Tukey's test, whereas precision was assessed with the Levene test (α=0.05). ResultsThe mean linear deviation (Δd) and standard deviation (SD) of VOR were both significantly affected by marker position (P < 0.001), and a significant position × scanner interaction was detected (P < 0.001). Negative mean deviations were observed for the distally extended edentulous areas in both groups. PS scans exhibited trueness that was significantly better than that for TR scans in the D16–46, D13–43, D23–33, and D27–37 subgroups (P < 0.05), whereas there were no significant differences in the D25–35 or D26–36 subgroups. PS scanning was associated with significantly better precision than TR scanning (P < 0.001), and worse precision was observed at D27–37 for both tested IOSs. ConclusionsMandibular partial edentulous distal extension can significantly affect VOR accuracy. The type of IOS could also affect VOR accuracy depending on the area being scanned, with better overall performance observed for the Primescan device as compared to the Trios 4 scanner. Both of these IOSs tended to underestimate VOR occlusal dimensions in mandibular distally extended edentulous areas. Clinical SignificanceMandibular distal edentulous areas can contribute to occlusal dimensions that are underestimated in digital workflows, which may result in infraocclusal discrepancies that arise when performing restorations. IOSs and VOR scanning protocols should thus be carefully considered in order to minimize these risks.