Evaluation of subarcuate canal on CT images in the perspective of clinical basis.

OBJECTIVES: The aim of our study to contribute to the field of morphometrics by including measurements of the SAC and SAF and their distances from surrounding structures, particularly for surgeons involved in retrosigmoid approach for internal acoustic meatus tumor surgery and cerebellopontine angle surgery. Although there is limited information in the literature regarding the role of the subarcuate fossa (SAF) and subarcuate canal (SAC), it has been suggested that the SAC may be a potential pathway for infection from the middle ear to the posterior cranial fossa, and cerebellar abscesses may have this origin. METHODS: For the images of our study, computerized tomography images of 118 individuals (59 females and 59 males) between the ages of 18-65 who applied to Bayindir Health Group. RESULTS: The width of the cranial opening of the subarcuate canal was determined as 44 ± 0.54 mm, width of the labyrinth opening of the subarcuate canal was determined as 60 ± 0.42 mm, Length of the subarcuate canal was determined as 8.79 ± 2.31 mm, width of the subarcuate canal was determined as 5.54 ± 1.75 mm, and depth of subarcuate fossa was determined as 1.67 ± 0.69 mm. The distance of the cranial opening of the subarcuate canal to the superior semicircular canal (SSC-SAC/C) was measured as 5.33 ± 1.81 mm, The distance of the labyrinth opening of the subarcuate canal to the superior semicircular canal (SSC-SAC/L) was measured as 3.90 ± .98 mm, length of the petrous part of the temporal bone medial to the anterior semicircular canal measured from the apex to the SSCD (PLM) was measured as 33.56 ± 0.42 mm. No statistically significant differences were found between the right and left sides. CONCLUSIONS: The morphometric measurements obtained in this study can provide useful information for neurosurgeons, neurotologist and otolaryngologists involved in retrosigmoid approach for internal acoustic meatus tumor surgery and cerebellopontine angle surgery, and for patients undergoing cochlear implant planning with a retrofacial approach.

The micro CT evaluation of crown and root pulp volume versus dentin thickness in teeth in postmortem interval (PMI).

Determining the postmortem interval (PMI) is one of the main study subjects of forensic sciences. The main purpose of this prospective in vitro study that was the Micro-CT evaluation of teeth crown and root pulp volume versus dentin thickness in terms of PMI determination. The study involved 60 female Wistar rats, with weights ranging from 270 to 320 g. These rats were grouped into six different post-mortem period categories. Following the animals' sacrifice, they were subjected to a natural putrefaction period, with a control group, in the grounds of a sheltered garden. Hemi-mandible samples were then extracted and placed in glass tubes for Micro-CT evaluations, following the progression of putrefaction processes. The pulp volume and dentin thickness were assessed using Micro-CT, and the gathered data underwent statistical analysis. Micro-CT was employed to analyze sixty right mandibular second molar teeth in the hemi-mandible. The crown pulp volume exhibited a reduction in group 6, with a value of 0.239 mm3 after a three-month period of natural putrefaction (p < 0.001). There is statistically differences among groups in case of pairwise comparison (p < 0.05). However, the root pulp volume and dentin thickness variables did not display any statistically significant changes. Despite certain limitations associated with this study, the Micro-CT findings concerning teeth pulp volume can serve as an objective parameter, especially for late postmortem investigations and the estimation of time of death.

Effect of different preparation finishing procedures on the marginal and internal fit of CAD-CAM-produced restorations: A microcomputed tomography evaluation.

STATEMENT OF PROBLEM: Accurate fit is an important factor for the longevity of computer-aided design and computer-aided manufacturing (CAD-CAM) ceramic restorations. Few studies have compared how restoration finishing procedures affect the marginal and internal fit of these restorations by using microcomputed tomography (µCT). PURPOSE: The purpose of this in vitro study was to evaluate the preparations with different surface finishing procedures for the fit of CAD-CAM restorations by using µCT. MATERIAL AND METHODS: A total of 28 anatomic contour monolithic feldspathic ceramic crowns were produced for 4 typodont teeth prepared according to the different surface finishing procedures (n=7). The generated experimental groups were finishing with extra-coarse (181 µm) diamond rotary instruments (EC), finishing with fine (40 µm) diamond rotary instruments after extra-coarse diamond rotary instruments (F), finishing with very fine (20 µm) diamond rotary instruments after extra-coarse and fine diamond rotary instruments (VF), and finishing with extra-coarse, fine, and very fine diamond rotary instruments followed by polishing rubber points (P). µCT scans were obtained to measure the gaps between the typodont teeth and the crowns. Reference points such as the margin, chamfer (the deepest point), cusp tips, and central fossa were determined, and 196 measurements were made. Data were analyzed by using 2-way analyses of variance and the Tukey HSD test (α=.05). RESULTS: The highest gap values in all sections were observed in the finishing with extra-coarse (181 µm) diamond rotary instruments group. The lowest gap value in the marginal point was observed in the P group (P<.05). In total, the gap values of the reference points were in the order of margin, chamfer, cusp, and central fossa. CONCLUSIONS: µCT evaluation showed that tooth preparation finishing procedure with finer grit rotary instruments yielded better marginal fit for monolithic feldspathic CAD-CAM restorations. The internal gap values of all groups were also in the range of clinically acceptable values, important for mechanical properties.

Comparison of three different biomaterials used in in vitro molar apexification models.

OBJECTIVES: New biomaterials had some advantages such as mixing and easier application as compared to traditional MTA in single step apexification method. This study aimed to compare the three biomaterials used in the apexification treatment of immature molar teeth in terms of the time spent, the quality of the canal filling and the number of x-rays taken to complete the process. METHODS: The root canals of the extracted thirty molar teeth were shaped with rotary tools. To obtain the apexification model, ProTaper F3 was used retrograde. The teeth were randomly assigned into three groups based on the material used to seal the apex; Group 1: Pro Root MTA, Group 2: MTA Flow, Group 3: Biodentine. The amounts of the filling, the number of radiographs taken until treatment completion and the treatment duration were recorded. Then teeth were fixed for micro computed tomography imaging for quality evaluation of canal filling. RESULTS: Biodentine was superior to the other filling materials according to time. MTA Flow provided greater filling volume than the other filling materials in the rank comparison for the mesiobuccal canals. MTA Flow had greater filling volume than ProRoot MTA in the palatinal/distal canals(p = 0.039). Biodentine had greater filling volume more than MTA Flow in the mesiolingual/distobuccal canals (p = 0.049). CONCLUSIONS: MTA Flow was found as a suitable biomaterial according to the treatment time and quality of root canal fillings.

Morphologic Mapping of the Sublingual Microcirculation in Healthy Volunteers.

PURPOSE: Monitoring the sublingual and oral microcirculation (SM-OM) using hand-held vital microscopes (HVMs) has provided valuable insight into the (patho)physiology of diseases. However, the microvascular anatomy in a healthy population has not been adequately described yet. METHODS: Incident dark field-based HVM imaging was used to visualize the SM-OM. First, the SM was divided into four different fields; Field-a (between incisors-lingua), Field-b (between the canine-first premolar-lingua), Field-c (between the first-second premolar-lingua), Field-d (between the second molar-wisdom teeth-lingua). Second, we investigated the buccal area, lower and upper lip. Total/functional vessel density (TVD/FCD), focus depth (FD), small vessel mean diameters (SVMDs), and capillary tortuosity score (CTS) were compared between the areas. RESULTS: Fifteen volunteers with a mean age of 29 ± 6 years were enrolled. No statistical difference was found between the sublingual fields in terms of TVD (p = 0.30), FCD (p = 0.38), and FD (p = 0.09). SVMD was similar in Field-a, Field-b, and Field-c (p = 0.20-0.30), and larger in Field-d (p < 0.01, p = 0.015). The CTS of the buccal area was higher than in the lips. CONCLUSION: The sublingual area has a homogenous distribution in TVD, FCD, FD, and SVMD. This study can be a description of the normal microvascular anatomy for future researches regarding microcirculatory assessment.

Micro-CT evaluation of 'danger zone' and microcrack formation in mesial root canals of primary teeth with single-file rotary and reciprocating systems.

BACKGROUND: Although single-file rotary systems are accepted in the field of paediatric dentistry in terms of providing time advantage, research works continue due to the variable anatomical structure of the root canal. AIM: This study aimed to evaluate rotary systems in different kinematics in terms of microcracks and the shaping of the danger zone in primary molars by micro-CT. DESIGN: The mesial canals of primary molars (n = 30) were used. Root canals in each group (n = 10) were prepared with single-file rotary systems (One Shape®, OS; XP-endo® Shaper, XP-ES; WaveOne Gold, WOG). The images were evaluated for dentin thickness in the danger zone and microcrack formation. RESULTS: WOG caused the highest dentin reduction in the danger zone area. OS led to significantly less dentin reduction than XP-ES and WOG (P < .05). The XP-ES showed the highest number of microcracks (P < .05). No statistically significant difference was found between WOG and OS (P > .05). In all systems, more microcracks were observed in the middle third than coronal and apical. CONCLUSION: Within the limitations of this study, the rotary systems were superior to reciprocating in terms of shaping ability in the danger zone. It is thought that further studies with different systems should be designed considering the anatomical variations and chemical composition of primary teeth.

Investigation of the effect of ghrelin on bone fracture healing in rats.

Ghrelin is known to have effects on proliferation and differentiation of osteoblasts and improvement of bone mineral density in rats. However, no experimental research on ghrelin's effects on fracture healing has been reported. In this context, the effect of ghrelin on the union of femoral shaft fractures was examined in this study by evaluating whether ghrelin will directly contribute to fracture healing. Forty male Wistar-Albino rats were divided into two groups as control and experimental (ghrelin treated) and standard closed shaft fractures were created in the left femurs of all rats. Daily ghrelin injections were applied to the experimental groups and equal numbers of rats were killed after 14 and 28 days following fracture formation. Tissue samples were examined with radiological, biomechanical, biochemical and histological analyses. Densitometry study showed that bone mineral density was improved after 28 days of ghrelin treatment compared to control. On histological examination, at the end of the 14 and 28 days of recovery, significant union was observed in the ghrelin-treated group. The ghrelin-treated group had higher breaking strength and stiffness at the end of 28 days of recovery. Biochemically, ALP levels were found to be higher in the ghrelin-treated group at the end of 28 days of recovery. Results showed that ghrelin directly contributes to fracture healing and it is promising to consider the effect of ghrelin on fracture healing in human studies with pharmacological applications.

Can the Combination of Simvastatin and Melatonin Create a Synergistic Effect on Bone Regeneration?

PURPOSE: The present study evaluated the potential bone regeneration capacity of combining melatonin and simvastatin, with a goal of producing more osteogenic bone substitutes. MATERIALS AND METHODS: A total of 48 male Wistar rats were randomly divided into 4 groups. The following were administered into critical-sized calvarial defects of the rats: Group I-human allograft; Group II-human allograft + 10 mg melatonin; Group III-human allograft + 0.1 mg simvastatin; and Group IV-human allograft + 10 mg melatonin + 0.1 mg simvastatin. Histopathologic, histomorphometric, and microcomputed tomographic evaluations were performed postprocedurally at 4 and 8 weeks. A P value < .05 was considered significant for all evaluations. RESULTS: Groups II and III had significantly superior regeneration compared to Group I at weeks 4 and 8. Group III had significantly superior regeneration compared to Group II, particularly in week 4. Group IV had significantly superior regeneration compared to all groups at week 8. CONCLUSIONS: The local administration of melatonin and simvastatin resulted in increased new bone mass and quality of bone microstructure than was seen in the control group. Simvastatin shortened the defect regeneration time more effectively than melatonin did. The combined use of melatonin and simvastatin provided a synergic effect on bone regeneration, particularly in the late phase of healing.

Marginal and internal fit of feldspathic ceramic CAD/CAM crowns fabricated via different extraoral digitization methods: a micro-computed tomography analysis.

The aim of this study was to compare the fit of feldspathic ceramic crowns fabricated via 3 different extraoral digitizing methods. Twelve maxillary first premolars were prepared and 36 single crowns were fabricated via 3 extraoral digitizing methods using a laboratory scanner (n = 12): (1) scanning the typodont (ST [control] group); (2) scanning the impression (SI group); (3) scanning the stone cast (SC group). Micro-computed tomography was used to calculate two-dimensional marginal-internal gap and the three-dimensional volumetric gap between the crowns and their corresponding dies. The measured gaps were divided into 6 location categories as follows: marginal gap (MG), finish line gap (FLG), axial wall gap (AWG), cuspal gap (CG), proximal transition gap (PTG), and central fossa gap (CFG). The correlation between each of the 3 extraoral digitizing methods and the adaptation status of the crown margins were also evaluated. The Wilcoxon signed-rank test, Spearman's rank test, and Chi-square test were used for data analysis (α = 0.05). The marginal gaps in the ST, SI, and SC groups differed significantly (24, 198 and 117.6 µm, respectively) (p < 0.05). Significant differences were found between the groups with regard to internal gap measurements, with SI representing higher gap measurements at FLG, PTG and CFG locations (p < 0.05). 3D volumetric gap measurements did not differ significantly (p > 0.05). Under-extended margins observed in the SI and SC groups were correlated with the digitizing method (Cramer's V-square: 0.14). When performing extraoral digitalization, clinicians should choose to scan the stone cast as scanning the stone cast resulted in better internal and marginal fit compared to scanning the impression.

Evaluation of Denture Base Adaptation Fabricated Using Conventional, Subtractive, and Additive Technologies: A Volumetric Micro-Computed Tomography Analysis.

PURPOSE: An in vitro study to compare the adaptation of denture bases fabricated with 4 different techniques using volumetric 3-dimentional (3D) analysis. MATERIAL AND METHODS: Edentulous maxillary and mandibular casts were scanned, and standardized denture bases were designed using CAD design software. The same standard tessellation language (STL) data were used to produce the denture bases with 4 different fabrication methods: compression molding (CM), injection molding (IM), PMMA milling (PM), and 3D printing (3D) (n = 11/group). Milled wax denture bases were used to fabricate CM and IM groups. Denture bases placed on edentulous casts were scanned using micro-computed tomography (micro-CT). Volumetric gap between denture base and cast was calculated from 6 locations for maxilla (anterior ridge crest, posterior ridge crest, labial vestibule, buccal vestibule, palate, and posterior palatal seal) and 3 locations for mandible (intermolar, molar, and retromolar) in addition to overall gap measurements for edentulous arches. The data were analyzed with factorial analysis of variance (ANOVA), 1-way ANOVA, and post-hoc Duncan tests. Reproducibility of fabrication methods with regard to each location was assessed using Z test (α = 0.05). RESULTS: In the maxilla, the highest and lowest palatal gap measurements were recorded for CM (898.44 ± 87.73 mm3 ) and PM (357.16 ± 57.68 mm3 ) (p = 0.05). The highest gap measurements for CM and 3D were at palate and, for IM and PM were at posterior ridge crest. In mandible, the volumetric gap measurements for CM were the highest and for PM were the lowest irrespective of location (p = 0.05). PM group showed the best reproducibility and adaptation with the lowest overall mean gaps for both edentulous arches (p = 0.05). CONCLUSIONS: Denture bases milled from PMMA blocks showed better adaptation than 3D printed, or wax milled and conventionally fabricated denture bases for both maxillary and mandibular arches. PMMA milling is a reproducible technique that enables the construction of accurate dentures. Clinicians should be cautious about the palatal gap when the compression molding technique is used. Micro-CT is a valid technique for evaluating the denture base adaptation.

The micro-CT evaluation of enamel-cement thickness, abrasion, and mineral density in teeth in the postmortem interval (PMI): new parameters for the determination of PMI.

OBJECTIVE: The estimation of time of death or the determination of the postmortem interval (PMI) is one of the most important issues in forensic medicine and odontology. However, evaluation of bone and dental hard tissues in PMI could be challenging due to the lack of objective methods with high accuracy. In this respect, micro-CT analysis which has not been used for postmortem evaluation would be beneficial in evaluating hard tissues such as bones and teeth. Therefore, the aim of the present study was to determine the alterations in the hard dental tissue, mineral density of enamel, and the surface abrasion of hard dental tissues of rats in the PMI period with a relatively novel method, micro-CT. METHODS: The present study included 60 female Wistar rats which were divided into six study groups. The rats were sacrificed at the baseline and were left into nature putrefaction process. The study groups were created based on the PMI period as week-0, week-1, week-2, week-4, week-8, and week-12, which included 10 rats in each group. All hemi-mandibles were collected in the determined timelines and the micro-CT analysis was carried out on each group. Mineral density of enamel and the surface abrasion of hard dental tissues were determined. RESULTS: The enamel and cement thickness remained the same in the examined PMI periods. Mineral density of the enamel tissues were also similar until the 8th week but the decrease was significant at 12th week (2.313 gHAp cm3). Surface abrasion of the dental tissues on weeks 4, 8, and 12 were 0.006, 0.024, and 0.024 mm, respectively. CONCLUSION: The present study indicated that surface abrasion and enamel mineral density evaluation via micro-CT can be considered as objective and precise parameters in PMI evaluation in forensic medicine and odontology.

Evaluation of the Sigmoid Sinus Morphology by Cone Beam Computed Tomography; Touchstone of the Posterior Cranial Fossa.

OBJECTIVE: In this study, we aimed to analyze the relationship of the sigmoid sinus (SS) with the external auditory canal, facial nerve, and mastoid cells from an anatomic point of view, to define the position of the SS during transmastoid, translabyrinthine, retrosigmoid (lateral suboccipital) approaches, in tympanomastoidectomy and posterior cranial fossa surgery. METHODS: In this study, the morphologic structures associated with the sigmoid sinus were evaluated in cone beam computed tomography images taken between 2015 and 2022. The images of 68 men and 106 women, aged 18-65 years, obtained from the archive of Ankara University Faculty of Dentistry, Department of Oral and Maxillofacial Radiology were analyzed. RESULTS: The most common SS pattern was type II, with a rate of 60.8% (n = 209); the second was type III, with 20.6% (n = 71); and the least common was type I, with 18.6% (n = 64). Although the distance between the horizontal line passing through the external auditory canal and facial nerve and the anterior contour of the SS was highest in type I (right, 7.26 ± 1.62; left, 7.44 ± 0.97), it was lowest in type III (right, 4.40 ± 1.50; left, 4.84 ± 1.16) (P < 0.05). CONCLUSIONS: This study highlights the importance of the SS position in surgery, with special reference to otologic, neurotologic, and posterior cranial fossa surgery. To avoid intraoperative complications, each patient should be evaluated preoperatively by appropriate radiologic methods.

The effect of removable partial dentures on alveolar bone resorption: a retrospective study with cone-beam computed tomography.

PURPOSE: The aim of this study was to compare vertical and horizontal mandibular alveolar bone resorption by measuring bone morphological variation in Kennedy Class II removable partial denture (RPD) wearers and non-wearers using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: In total, 124 sites in the CBCT scans of 62 (29 RPD non-wearers, 33 RPD wearers) Kennedy Class II patients were analyzed retrospectively. Three-dimensional representations of the mandible with superimposed cross-sectional slices were developed with the CBCT scans to evaluate the mandibular alveolar height and width by measuring distances between the mandibular canal, mylohyoid ridge, alveolar crest, and lower border of the mandible in four regions (eight sites) of Kennedy Class II non-wearers and wearers of RPDs. RESULTS: Mandibular alveolar bone height and width were significantly lower in edentulous sites when compared with dentate sites in both Kennedy Class II non-wearers and wearers of RPDs (p < 0.05). Additionally, mean vertical and horizontal mandibular bone resorption was significantly higher in RPD wearers than in non-wearers (p < 0.05). CONCLUSIONS: Vertical and horizontal alveolar bone resorption was found to be higher in the RPD wearing patients when comparing the dentate and edentulous sites.

Operational Analysis of Trautman's Triangle in Petroclival Region Approaches: Cone-Beam Computed Tomography Study.

OBJECTIVE: This study was conducted to evaluate the anatomical and clinical features of Trautman's triangle (TT) and to better understand the possible surgical corridor for other surgical approaches involving the petroclival region, especially the presigmoid retrolabyrinthine approach. METHODS: In this study, morphological analysis of structures related to TT was performed from cone beam computed tomography images of 134 female and 206 male individuals aged 18-65 years. RESULTS: The TT area was observed as 5.6% (n = 19) type I, 63.2% (n = 215) type II, and 31.2% (n = 106) type III. It was determined that 87.6% of the sigmoid sinus (SS) was lateral to the posterior semicircular canal and 12.4% was medial. It was determined that the TT area showed a positive correlation with petrous slope and a negative correlation with mastoid aeration. In other words, as the TT area increased, the petrous inclination angle also increased, but the mastoid aeration decreased. It was also found that the TT area was associated with the location of the SS and the largest TT area (164.84 ± 42.29 mm2) was observed in the posteriorly located SS. CONCLUSIONS: The relationship between TT and SS, petroclival angle, mastoid aeration, and subarcuate fossa has a very dynamic structure. Understanding the variations and clinical significance of these structures in the petroclival region is critical in determining the surgical approaches to be applied and understanding the etiology of vestibular system diseases.

Clinical and variational evaluation of peroneus tertius muscle.

This research was conducted to define the typology of the peroneus tertius, which is considered to be a part of the musculus extensor digitorum muscle and plays a role in dorsiflexion and eversion of the foot. In addition, another aim of the study was to examine the relationship of the peroneus tertius with the extensor digitorum longus and to investigate the possible effects of the tendon/insertio properties of the peroneus tertius on the fifth metatarsal. In this study; classical anatomical dissection was performed on 30 lower limbs. In this study, various parameters related to muscle origin, insertion, tendon and muscle dimensions were measured. It has been found that PTM was absent in 26.6% of the specimens and in 23.3% (n = 7) of the cases PTM was directly originated from the EDL. In 56.7% of the specimens (n = 17), the PTM tendon was mutually inserted into the dorsomedial surface of the 5th metatarsal and dorsolateral of the 4th metatarsal, while in 10.0% of the specimens it has thin medial bands (2 × 1 mm) towards the 5th digit. At the end of the study, the PTM origin was categorized into three different types and PTM insertion was categorized into five different types. Variation of PTM, muscle morphology and tendon diameter are extremely important in terms of minimally invasive surgical technique. Since the accessory tendon must have the properties close to the tendon that will be replaced, we believe that the results of our research provide unique useful information to clinicians. This study is the cadaver research.

Clinical and anatomical importance of foramen magnum and craniocervical junction structures in the perspective of surgical approaches.

This study was conducted to investigate the clinical and anatomical importance of the relevant region from the perspective of surgical approaches by determining the morphometric analysis of the craniocervical junction and foramen magnum (FM) region and determining their distances from important anatomical points. This research was carried out with 59 skulls found at the Anatomy Laboratories of Erciyes and Ankara Medipol University. Metric measurements of FM and condyle, FM shape, condyle-fossa relationship, and pharyngeal tubercle (PT) were made in mm-based dry bone samples of unknown age and sex. The distance between the anterior notches and the FM was 87.01±4.35, the distance between the anterior notches and the PT was 77.70±4.24, the distance between the PT-sphenooccipital junction was 13.23±2.42, and the FM index was 81.86±7.47. The anteroposterior and transverse lengths of FM were determined as 33.80±2.99 and 27.72±2.30, respectively. The morphometric and morphological data available regarding the craniocervical junction showed significant differences between populations. Comprehensive knowledge of this topic will provide a better approach to treat Arnold Chiari Malformation, FM meningiomas, and other posterior cranial fossa lesions. Therefore, we believe that FM and craniocervical junction morphology will be a guide not only for anatomists, but also for radiologists, neurosurgeons, ENT surgeons, and orthopedists.

The Effect of Mobile Applied Anatomy Learning on Students' Academic Success, Cognitive Loads, and Attitudes.

Purpose/Objectives: Anatomy has always been one of the most important components of Health Science education. Worldwide, anatomy education is given in an environment based on cadaver, touch and 3D designs. However, this process has become quite difficult as the pandemic restricted use of laboratory procedures, models, and other learning materials. Therefore, education with mobile applications has become much more important. The aim of this study was to measure the effect of mobile applications used in anatomy course, which is one of the courses that form the basis of medical science, on the success levels of students, and to evaluate their perspectives on this method. Methods: In this study, a real experimental research model with pretest-posttest control group was used in order to determine the difference that may occur between academic achievement and cognitive load when anatomy course students use traditional method or mobile application technology learning method. Results: The findings of the study showed that the students in the experimental group, in which mobile applications were used in the anatomy course, had higher achievement levels and lower cognitive loads than the students in the control group. Another point that was determined was that the students in the experimental group were satisfied with the fact that the use of the mobile application facilitated learning, and they learned better as the ease of use in the mobile application increased.

Cervicofacial emphysema after dental treatment with emphasis on the anatomy of the cervical fascia.

Fascial organization of the neck is quite complex and highly variable between individuals. Fascial layers separate very important structures in the neck, and by this way, they build anatomical walls against spread of infections, although this alignment could lead to spread of infection very easily throughout connected fascial spaces. We tried to discuss the possible anatomical pathways resulting in cervicofacial emphysema with a case.The development of cervicofacial emphysema after dental treatment is a well-known complication especially when using high-speed turbines. A 39-year-old female patient is referred to our private dental clinic with complaints of swelling on her right supraclavicular region with edema of right orbita with absence of pain. In our case, emphysema reaches to supraclavicular region using retropharyngeal space and prevertebral fascia.This case illustrates anatomically how air or other materials, including pathogens or infections, could pass easily from oral cavity into thorax or even abdomen using facial planes.

Effect of different resin removal methods on enamel after metal and ceramic bracket debonding : An in vitro micro-computed tomography study.

PURPOSE: The aim of this study was to conduct an in vitro evaluation of the effects of different adhesive debonding and polishing techniques performed after metal and ceramic bracket removal on enamel using micro-computed tomography (micro-CT). METHODS: This study was performed on 42 extracted maxillary first premolars divided into 2 main groups and 6 subgroups as follows: metal (group 1) or ceramic (group 2) brackets were bonded to the teeth, then, after debonding, one of three different methods was used to remove the residual adhesive: tungsten carbide burs with pumice (A), fiber-reinforced composite burs and polishing paste (B), or Sof-Lex discs (C; 3M Dental, St Paul, MN, USA). The samples were evaluated by micro-CT before bracket bonding (T0) and after resin removal (T1). Demineralization area, demineralization depth, demineralization volume, mineral density, and mineral volume were measured. RESULTS: At T1, demineralization area was significantly larger in groups 1A and 2A compared to groups 1B, 1C, 2B, and 2C (P = 0.001). Group 2A (ceramic bracket/tungsten carbide-pumice) had the highest demineralization volume (P = 0.001). When the groups were compared in terms of change from T0 to T1, groups 1A and 2A showed significantly larger changes in demineralization area compared to the other 4 groups (P = 0.001). The increase in demineralization volume was larger in group 2A compared to all other groups (P = 0.001). CONCLUSION: All resin removal methods damaged the enamel surface to varying degrees. Regardless of bracket type, the use of tungsten carbide and pumice should be avoided when cleaning the tooth surface after debonding. Use of composite burs and Sof-Lex discs in particular after the debonding of ceramic brackets will help minimize damage.