Comparison of the amount of artifacts induced by zirconium and titanium implants in cone-beam computed tomography images.

BACKGROUND: This study aimed to compare the amount of artifacts induced by the titanium and zirconium implants on cone-beam computed tomography (CBCT) and assess the effect of different exposure settings on the image quality for both materials. METHODS: In this experimental study, 30 zirconium and 30 titanium implants were placed in bovine rib bone blocks. CBCT images were taken in two different fields of view (FOV: 4 × 6 cm2 and 6 × 8 cm2) and at two resolutions (133 µ and 200 µ voxel size). Subsequently, two observers assessed the images and detected the amount of artifacts around the implants through gray values. Data were analyzed by paired t test and independent t test using SPSS 21 and the 0.05 significance level. RESULTS: The results showed that titanium implants caused lower amounts of artifacts than zirconium implants, which was statistically significant (P < 0.001). The larger FOV (6 × 8 cm2) resulted in a lower amount of artifacts in both groups, although the results were only statistically significant in the zirconium group (P < 0.001). The amount of artifacts was increased when using the 133 µ voxel size in both groups, which was only significant in the zirconium group (P < 0.001). CONCLUSION: Our results suggest that zirconium implants induce higher amounts of artifacts than titanium ones. We also concluded that the artifacts could be minimized using the larger FOV and voxel size.

3D-printed bi-layered polymer/hydrogel construct for interfacial tissue regeneration in a canine model.

OBJECTIVES: There are complications in applying regenerative strategies at the interface of hard and soft tissues due to the limited designs of constructs that can accommodate different cell types in different sites. The problem originates from the challenges in the adhesion of dissimilar materials, such as polymers and hydrogels, that can be suitable for regenerating different tissues such as bone and soft tissues. This paper presents a design of a new hybrid construct in which a polymer (polycaprolactone (PCL)) membrane firmly adheres to a layer of hydrogen (gelatin). METHODS: PCL membranes with defined size and porosity were fabricated using 3D printing. The gelatin layer was attached to the PCL membranes using the aminolysis procedure. We have examined this construct for the application of Guided Bone Regeneration (GBR) as a typical surgical regenerative procedure of the oral cavity at the interface of bone and soft tissue. Complete in vitro and in vivo investigations on canine tibia bone defects have been performed. Histological analyses for fibrosis morphometric and bone morphometric evaluation, as well as bone-fibrosis histological grading and CBCT imaging, were conducted. RESULTS: Chemical and morphological studies of the membrane proved that gelatin was uniformly attached to the aminolyzed PCL membranes. The in vitro and in vivo studies indicated the membrane's biocompatibility, mechanical stability, and barrier function for the GBR application. Furthermore, in vitro study showed that the membranes could improve osteogenesis and the regeneration of bone defects. The results illustrated that the mean bone density in the membrane groups was about three times more than that of the control group. SIGNIFICANCE: The fabricated 3D-printed hybrid Gelatin/PCL bi-layered membrane can be a good candidate for interfacial tissue engineering and a promising membrane for GBR procedure.

Complementarity of surgical therapy, photobiomodulation, A-PRF and L-PRF for management of medication-related osteonecrosis of the jaw (MRONJ): an animal study.

BACKGROUND: This study aimed to evaluate the complementarity of surgical therapy, photobiomodulation (PBM), advanced platelet-rich fibrin (A-PRF), and Leukocyte and platelet-rich fibrin (L-PRF) for the management of medication-related osteonecrosis of the jaw (MRONJ). METHODS: Sixty rats underwent injection of zoledronate followed by left mandibular first and second molar extractions to induce MRONJ lesions. All rats were examined for the signs of MRONJ 8 weeks post-dental extraction. Forty-nine rats with positive signs of MRONJ were appointed to seven different groups as follows: control (Ctrl); surgery alone (Surg); surgery and PBM (Surg + PBM); surgery and A-PRF insertion (Surg + APRF); surgery and L-PRF insertion (Surg + LPRF); surgery, A-PRF insertion, and PBM (Surg + APRF + PBM); surgery, L-PRF insertion, and PBM (Surg + LPRF + PBM). Euthanasia was carried out 30 days after the last treatment session. The lesions' healing was evaluated clinically, histologically, and radiographically. Data were analyzed using STATA software version 14, and the statistical significance level was set at 5% for all cases. RESULTS: According to the present study, A-PRF and L-PRF treatment resulted in significant improvements in clinical, histological, and radiographical parameters compared to the Ctrl group (P < 0.05). The PBM also decreased wound dimensions and the number of empty lacunae compared to the Ctrl group (P < 0.05). Surg + APRF + PBM and Surg + LPRF + PBM were the only groups that presented a significantly higher mean number of osteocytes (P < 0.05). No significant differences were observed between A-PRF and L-PRF treatment groups (P > 0.05). CONCLUSIONS: Surgical resection followed by applying A-PRF or L-PRF reinforced by PBM showed optimal wound healing and bone regeneration in MRONJ lesions.

Primary intraosseous mandibular hydatid cyst: A case report and review of 97 cases of osseous cystic echinococcosis.

OBJECTIVE: In this study, we review the reported cases of hydatid disease of the bone in terms of etiology, pathogenesis, and histopathologic, serologic, and radiographic features and management of the disease. STUDY DESIGN: The present case study reports an extremely rare occurrence of intraosseous hydatid cysts in the orofacial region, wherein symptoms or signs of systemic hydatid disease were absent. We discuss the challenges encountered during the diagnosis and treatment of osseous hydatidosis and reviewed articles on osseous hydatidosis, including 97 cases. We also compare the aspects reported in previous cases of mandibular hydatid cyst with those of the present case. RESULTS: Hydatid cysts were found to be present in almost every bone of the skeleton in patients (mean age of 39.95 ± 19.67 years; range, 3-76 years). A slight male preference (58.8%) was observed. A history of rural lifestyle, animal bites, and trauma in the affected bone was reported. Only 5 reports on mandibular bone have been published previously, of which 3 were primary. CONCLUSION: Because of the lack of usual presentations and radiographic features, the presence of hydatid cysts in unusual anatomic locations makes differential diagnosis difficult. The potential risk of anaphylactic shock in susceptible individuals, high recurrence rate, and risk of secondary hydatidosis pose diagnostic and surgical challenges.

In vivo efficacy of 3D-printed elastin-gelatin-hyaluronic acid scaffolds for regeneration of nasal septal cartilage defects.

Nasal septal cartilage perforations occur due to the different pathologies. Limited healing ability of cartilage results in remaining defects and further complications. This study sought to assess the efficacy of elastin-gelatin-hyaluronic acid (EGH) scaffolds for regeneration of nasal septal cartilage defects in rabbits. Defects (4 × 7 mm) were created in the nasal septal cartilage of 24 New Zealand rabbits. They were randomly divided into four groups: Group 1 was the control group with no further intervention, Group 2 received EGH scaffolds implanted in the defects, Group 3 received EGH scaffolds seeded with autologous auricular chondrocytes implanted in the defects, and Group 4 received EGH scaffolds seeded with homologous auricular chondrocytes implanted in the defects. After a 4-month healing period, computed tomography (CT) and magnetic resonance imaging (MRI) scans were obtained from the nasal septal cartilage, followed by histological evaluations of new tissue formation. Maximum regeneration occurred in Group 2, according to CT, and Group 3, according to both T1 and T2 images with 7.68 ± 1.36, 5.44 ± 2.41, and 8.72 ± 3.02 mm2 defect area respectively after healing. The difference in the defect size was statistically significant after healing between the experimental groups. Group 3 showed significantly greater regeneration according to CT scans and T1 and T2 images. The neocartilage formed over the underlying old cartilage with no distinct margin in histological evaluation. The EGH scaffolds have the capability of regeneration of nasal cartilage defects and are able to integrate with the existing cartilage; yet, they present the best results when pre-seeded with autologous chondrocytes.

Photobiomodulation in Oral Medicine.

Objective: To provide a review of the literature about the photobiomodulation therapy (PBMT) dental treatment protocols in oral medicine based on validated clinical studies that have been published so far. Background data: The lack of effective therapies for the treatment of various types of oral diseases or the presence of invasive therapeutic methods along with the use of a wide range of medications has had a significant impact on the quality of life of these patients. PBMT as a noninvasive and nondrug method can play an influential role in the treatment of oral diseases. Methods: In this study, published clinical studies up to April 2019 were reviewed from library sources, Google Scholar, PubMed and Medline, Elsevier, Embase, Cochrane, Scopus, and Web of science (ISI). Results: In general, the findings of this study showed that PBMT has had a positive effect on the treatment of oral lichen planus, recurrent aphthous stomatitis, hyposalivation, pemphigus vulgaris, recurrent herpes simplex, burning mouth syndrome, bisphosphonate-related osteonecrosis of the jaw, trigeminal neuralgia, facial nerve paralysis, geographic tongue, and chronic sinusitis. Conclusions: PBMT can be effective (as an alternative treatment or in combination with other therapies) in improving symptoms or in the complete treatment of oral diseases. However, further clinical studies are still necessary to achieve more robust results.

Effect of exposure parameters of cone beam computed tomography on metal artifact reduction around the dental implants in various bone densities.

BACKGROUND: This study aimed to assess the effect of exposure parameters such as milliampere (mA) and field of view (FOV) of cone beam computed tomography (CBCT) on a metal artifact of dental implants placed in different bone densities. METHODS: A total of 27 bone blocks with different densities (nine were type 1, nine were types 2 and 3, and nine were type 4) were used in this in vitro, experimental study. These blocks were placed in mandibular wax models. The blocks were scanned after drilling (hole preparation) and after implant placement using Cranex3D imaging system with a 4 × 6 cm2and 6 × 8 cm2 FOV and 4 and 10 mA. Gray value of the bone blocks was recorded before and after placement of implants. RESULTS: In general, irrespective of bone density, the amount of artifacts was lower in small FOV compared to large FOV (P < 0.05). Change of mA had no effect on metal artifacts (P > 0.05). Artifacts in type 4 bone were greater than in other bone types (P < 0.05). Difference between type 1 and types 2 and 3 was not significant (P > 0.05). CONCLUSION: According to the results of this study, Peri-implant artifacts were seen in all bone types; the amount of artifacts in type 4 bone was higher than that in other types. Size of FOV and bone density affect the metal artifacts around dental implants; so that a smaller FOV can be used to decrease metal artifacts.

Comparison of Intra-Socket Bupivacaine Administration Versus Oral Mefenamic Acid Capsule for Postoperative Pain Management Following Removal of Impacted Mandibular Third Molars.

PURPOSE: Surgical removal of impacted third molar teeth is one of the most common surgical procedures performed in oral and maxillofacial surgery. Postoperative pain is a common and predictable occurrence after maxillofacial surgery. MATERIALS AND METHODS: This randomized double-blind clinical trial was conducted with a crossover design in which each patient served as his or her own control. Forty-six patients with similar bilateral impacted lower third molars were selected. In each patient, the intervention and control sides of the mandible were randomly determined at the end of surgery. If the removed tooth was in the intervention side, then the patient would receive bupivacaine and a placebo of mefenamic acid. If the impacted tooth was in the control side, then the patient would receive a mefenamic acid capsule and a placebo of bupivacaine. Pain severity was assessed using a visual analog scale. Data were analyzed using paired-sample t test and a P value less than .05 was considered statistically significant. RESULTS: Of 46 participants originally recruited, 43 were included in the present study. The mean postoperative pain score in patients who received bupivacaine was increased to a maximum 4 hours, with marked improvements after this time. The mean intensity of pain after administration of bupivacaine was lower than that of mefenamic acid capsules at different time points. Statistical analysis showed a relevant difference in pain intensity between the 2 study groups. CONCLUSION: The results of the present study showed that local administration of bupivacaine relieves postoperative pain after surgical removal of impacted third molar teeth.

Performance of Cone Beam Computed Tomography Systems in Visualizing the Cortical Plate in 3D Image Reconstruction: An In Vitro Study.

INTRODUCTION: Cortical bone is an important anatomical structure and its thickness needs to be determined prior to many dental procedures to ensure treatment success. Imaging modalities are necessarily used in dentistry for treatment planning and dental procedures. Three-dimensional image reconstruction not only provides visual information but also enables accurate measurement of anatomical structures; thus, it is necessarily required for maxillofacial examination and in case of skeletal problems in this region. AIMS: This study aimed to assess the ability of three Cone Beam Computed Tomography (CBCT) systems including Cranex 3D, NewTom 3G and 3D Promax for Three-Dimensional (3D) image reconstruction of the cortical plate with variable thicknesses. METHODS: Depending on the cortical bone thickness, samples were evaluated in three groups of ≤ 0. 5 mm, 0.6 -1 mm and 1.1-1.5 mm cortical bone thickness. The CBCT scans were obtained from each sample using three systems, their respective FOVs, and 3D scans were reconstructed using their software programs. Two observers viewed the images twice with a two-week interval. The ability of each system in the 3D reconstruction of different thicknesses of cortical bone was determined based on its visualization on the scans. The data were analyzed using SPSS and Kappa test. RESULTS: The three systems showed the greatest difference in the 3D reconstruction of cortical bone with < 0.5 mm thickness. Cranex 3D with 4×6 cm2 FOV had the highest and 3D Promax with 8×8 cm2 FOV had the lowest efficacy for 3D reconstruction of cortical bone. Cranex 3D with 4×6 cm2 and 6×8 cm2 FOVs and NewTom 3G with 5×5 cm2 and 8×5 cm2 FOVs showed significantly higher efficacy for 3D reconstruction of cortical bone with 0.6-1mm thickness while 3D Promax followed by NewTom 3G with 8×8 cm2 FOV had the lowest efficacy for this purpose. CONCLUSION: Most CBCT systems have high efficacy for 3D image reconstruction of cortical bone with thicknesses over 1 mm while they have poor efficacy for image reconstruction of cortical bone with less than 0.5 mm thickness. Thus, for accurate visualization of anatomical structures on CBCT scans, systems with smaller FOVs and consequently smaller voxel size are preferred.

Basic life support knowledge and skills of Iranian general dental practitioners to perform cardiopulmonary resuscitation.

BACKGROUND: When cardiopulmonary arrest occurs, the dentist's ability to perform cardiopulmonary resuscitation (CPR) is the most important factor to minimize morbidity and mortality. This study assessed the basic life support (BLS) knowledge and performance of general dental practitioners in Hamadan, Iran. MATERIALS AND METHODS: The participants in the study were 80 Iranian general dental practitioners who were chosen randomly. Their CPR knowledge was evaluated by verbal questions and their CPR skills were determined by CPR execution on a special manikin. Nearly 39% (n = 31) of dentists answered none of the questions and only 2.50% (n = 2) answered all of the questions correctly. Thirty six dentists had been participated CPR course after graduation. RESULT: There was a significant difference between dentists who participated in CPR training course and those that did not participate (P value = 0.000). Only 3.75% (n = 3) were able to perform CPR properly. CONCLUSION: The results showed that the amount of CPR knowledge and skills were low in participated Iranian general dental practitioners. However, CPR training courses after graduation increased the amount of knowledge significantly, thus, retraining CPR courses is necessary for dentists.

Pattern of maxillofacial fractures: a 5-year analysis of 8,818 patients.

BACKGROUND: This multicenter study assessed the demographics, prevalence, causes, types, treatment, and complications of maxillofacial (MF) fractures managed by MF surgeons nationwide. METHODS: This 5-year retrospective descriptive analytical chart study evaluated 8,818 patients treated for MF fractures from 2007 to 2012 at 11 medical centers. Parameters, including age, sex, cause of injury, site of injury, type of injury, fracture patterns, treatment modalities, and complications, were evaluated from patient charts and radiographs. Collected data were analyzed via t test or χ test using SPSS 20 (Chicago, IL). A p value of less than 0.05 was considered statistically significant. This retrospective chart study was exempt from institutional review board approval. RESULTS: There were 7,369 male patients (83.6%), 1,376 female patients (15.7%), and 73 patients (0.8%) of unknown sex (aged 6 months to 112 years); 39.54% (3,457 patients) were in the 21-year to 30-year age group (mean, 28.18 years). We found 5,737 mandibular fractures (65.1%); mandible fracture was the most common (p < 0.05), followed by maxillary (1,641, 18.6%), zygomatic (3,240, 36.0%), orbital floor (743, 8.4%), naso-orbitoethmoidal (472, 5.4%), nasal (848, 9.6%), and frontal (344, 3.9%) fractures. Road traffic accidents were the most common cause. Posttreatment documented complications included remaining neurosensory disturbance of the inferior alveolar nerve (16.01%) and the infraorbital nerve (15.5%), remaining neuromotor disturbance of the facial nerve (2.3%), blurred vision (2.43%), diplopia (3.2%), limitation of eye movement (1.6%), exophthalmoses (1.88%), blindness (0.8%), as well as postoperative infection and chronic osteomyelitis (1.0%). CONCLUSION: On the basis of our study, mandibular fractures, in males and resulting from road traffic accidents in the third decade of life, were significant findings. Although the prevalence of MF fractures, demographics, and causes vary from one country to another and awareness of these patterns can provide insight to prevention protocols, this study shows that, despite better law enforcement of traffic regulations, better roads, better automobiles, and the like, the pattern of MF fractures in Iran has not changed significantly during the past 10 years. LEVEL OF EVIDENCE: Epidemiologic study, level IV.

Temporary preservation of avulsed tooth in oral submucosal tissue: an experimental study in cat.

OBJECTIVE: The purpose of this study was to determine the ability of oral submucosal tissue to serve as a temporary storage medium for the maintenance of periodontal ligament (PDL) cell viability of avulsed teeth. MATERIALS AND METHODS: Thirty cats were divided into five groups. After extraction of three teeth in each cat, one tooth was put in the depth of cat's oral submucosal tissue and the other two teeth were put in Hanks' balanced salt solution (HBSS) and tap water. The teeth were removed after 8, 24, 48, 72, and 168 h from their mediums and sent for laboratory processing and counting of vital periodontal cells. RESULTS: Statistical analysis demonstrated that submucosal tissue kept PDL cells viable as good as HBSS. CONCLUSION: This animal study showed that the efficacy of oral submucosal tissue in maintaining the viability of human PDL cells is similar to that of HBSS.