Viscosupplementation in the upper and lower compartments of the temporomandibular joint checked by ultrasonography in an ex vivo and in vivo study.

Viscosupplementation (VS) of the temporomandibular joint (TMJ) aims to treat temporomandibular dysfunction (TMD) by stimulating synovial cells to improve intracapsular lubrication. The purpose of the present study was to assess a VS protocol planned with the aid of cone-beam computed tomography (CBCT) and checked by ultrasonography (US). The study was carried out in 3 stages. The first was to check the correspondence between the proposed facial reference points and the osseous components of the joint by means of CBCT. In the second stage, the upper and lower compartments of 20 TMJs of fresh frozen cadavers were injected with coloured liquids, and the accuracy of the technique was confirmed by dissecting the anatomical specimens. The third stage consisted of VS in 10 patients (20 TMJs), with real-time verification of the location of the needle tip by means of ultrasonography. CBCT confirmed the correct locations of the marked points used in the proposed VS protocol. The dissections showed that 13 of the 14 injections effectively reached the upper and lower compartments. The location of the needle tip was effectively verified by ultrasonography, confirming the correct access to both compartments. The proposed protocol was effective for accessing the upper and lower compartments of the TMJ. The evaluated protocol proved to be accurate, safe and clinically reproducible means of VS in the upper and lower compartments of the TMJ.

Effects of root canal enlargement on unprepared areas and coronal dentine thickness of three-rooted maxillary first premolars with different root configurations: A stepwise micro-CT study.

AIM: To evaluate the effects of progressive root canal enlargements on the unprepared surface area and remaining dentine thickness of three-rooted maxillary first premolars with different root configurations. METHODOLOGY: Thirty three-rooted maxillary first premolars with three root configurations (n = 10) were selected and scanned in a micro-CT device. The root canals were sequentially enlarged with rotary instruments sizes 30.02 (step 1), 30.04 (step 2) and 30.06 (step 3). After each step, a new scan was taken. Analysed parameters included morphometric measurements (length, volume and surface area), number of static voxels and minimal dentine thickness. Statistical analyses were performed with one-way anova post hoc Tukey tests and paired sample t-test at a significance level of 5%. RESULTS: No statistical differences were observed amongst groups regarding the morphometric parameters and static voxels (p > .05). The minimal dentine thickness of the distobuccal root significantly changed depending on the root configuration (p < .05), whilst no differences were observed in the other roots (p > .05). A great variation in the position of the minimal dentine thickness was observed after preparation. Overall, mean percentage reduction in dentine thickness was higher in the buccal roots than in the palatal root (p < .05). In the mesiobuccal and distobuccal root, the number of slices with minimal dentine thickness lower than 0.05 mm increases 2 to 3 times and 3 to 4 times, respectively, from steps 1 to 3. CONCLUSIONS: Instruments sizes 30.02 and 30.04 can be safely and effectively used to enlarge the buccal and palatal canals of three-rooted maxillary first premolars.

Accuracy evaluation of 3D-printed guide-assisted flapless micro-osteoperforations in the anterior mandible.

AIM: To evaluate the accuracy of tridimensional (3D)-printed guide-assisted flapless cortical bone micro-osteoperforations (MOPs) in the anterior mandible on a cadaver model. MATERIALS AND METHODS: Five human cadaver heads with complete dentition in the anterior mandible were used in the present study. Preplanning CBCT and intraoral surface scans were obtained. After alignment, drilling sites in the interradicular areas were planned from canine to canine, and a surgical guide was printed. The drilling was performed and a postprocedure CBCT scan was obtained to assess the accuracy of the procedure in relation to the virtual planning. RESULTS: The mean ± standard deviation (SD) mesiodistal interradicular space was 2.67 ± 0.84 mm. The mean ± SD error of the actual drilled hole compared with the planned position of the mesial drill site was 0.66 ± 0.33 mm, and to the distal drill site it was 0.56 ± 0.33 mm. There was a statistically significant difference between the number of times the teeth were hit mesially (10 out of 64 holes) and distally (none). CONCLUSIONS: The proposed technique, limited to an ex vivo scenario, provides a valid and reliable method for mandibular MOPs using a 3D-generated surgical guide. However, the risk of damaging adjacent radicular surfaces, particularly in areas with limited mesiodistal interradicular bone, needs to be considered. Further studies should focus on using thinner drills and adding other methods to stabilize the guide. Additionally, by selecting individuals and perforation sites with more mesiodistal interradicular bone, less damage is likely. (Int J Comput Dent 2022;25(4):387-0; doi: 10.3290/j.ijcd.b2599841).

A simplified CAD/CAM extraoral surgical guide for therapeutic injections.

Therapeutic injections into the craniofacial region can be a complex procedure because of the nature of its anatomical structure. This technical note demonstrates a process for creating an extra-oral template to inject therapeutic substances into the temporomandibular joint and the lateral pterygoid muscle. The described process involves merging cone-beam computed tomography data and extra-oral facial scans obtained using a mobile device to establish a correlated data set for virtual planning. Virtual injection points were simulated using existing dental implant planning software to assist clinicians in precisely targeting specific anatomical structures. A template was designed and then 3D printed. The printed template showed adequate surface fit. This innovative process demonstrates a potential new clinical technique. However, further validation and in vivo trials are necessary to assess its full potential.

Effectiveness of Deworming with Single-Dose Albendazole for Preschool-Aged Children in the Dominican Republic.

Background. The World Health Organization recommends biannual deworming with single-dose albendazole for all children over 1 year in regions where soil-transmitted helminths (STH) are endemic. There are limited data from the Dominican Republic (DR) on the effectiveness of deworming programs. Methods. Between January and June 2019, we enrolled 63 preschool-aged children at a community clinic in the DR. Participants received albendazole at enrollment. Stool samples were collected and examined for parasites at enrollment, 2 to 4 and 12 to 16 weeks post-albendazole. Caregivers were surveyed on home hygiene practices and children's symptoms. Findings. At enrollment, 1 or more parasites were noted in 89% of samples. Ascaris lumbricoides (68%) was the most common species, followed by Entamoeba histolytica (35%) and Giardia intestinalis (8%). Two-to-four weeks post-albendazole, fewer than half of those with A. lumbricoides infections at baseline had cleared the infection. STH symptoms significantly improved between enrollment and 2 to 4 weeks. By 12 to 16 weeks after treatment, A. lumbricoides infections were as high as baseline. Interpretation. Although limited by size and available technology, our study contributes data on STH in the DR. Single-dose deworming with albendazole did not reduce Ascaris lumbricoides infections in our sample. As STH are the most common neglected tropical diseases and negatively impact children's health globally, further studies on both effective deworming programs and interventions to prevent STH are needed.

Positioning accuracy assessment of minimally invasive percutaneous injection techniques for the treatment of temporomandibular disorders.

OBJECTIVE: The aim of the present study was to evaluate the accuracy of an extraoral CBCT-planned 3D-printed surgical guide aimed to percutaneous injection of substances into the temporomandibular joint (TMJ) and the lateral pterygoid muscle (LPM). METHODS: Nine human cadaver heads were used. Pre-planning CBCT and facial scans were obtained and three percutaneous injection sites were planned: one for the lower compartment of the TMJ and two for the LPM. A digital surgical guide was then designed with small titanium sleeves and printed by a 3D printer. After the injections, new CBCT scans with the needles in place were obtained in order to assess the accuracy of the procedure in relation to the virtual planning. RESULTS: The mean values for angle deviation were very low (range 1.13o-4.08o), the same happening for the mean difference in the length reached (range 1.82-2.64 mm), as well as for the mean difference in the needle tip dislocation (range 0.94-2.03 mm). CONCLUSION: The guide seems to be a reliable tool for accurate percutaneous injection of drugs into the inferior compartment of the TMJ and the LPM. Further studies are necessary to test the efficacy and validate the method in an in vivo study.

Zygomaticofacial, Zygomaticoorbital, and Zygomaticotemporal Foramina.

This study aimed to assess the anatomical and morphometric characteristics of the main zygomaticofacial (ZFF), zygomaticoorbital (ZOF), and zygomaticotemporal (ZTF) foramina in Brazilian dry skulls. 61, 69, and 42 skulls for ZFF, ZOF, and ZTF were evaluated by a single calibrated examiner for format, transverse and vertical diameters, and distances from the foramina to anatomical landmarks. Paired t test, Wilcoxon test, Pearson and Spearman correlations were used. Circular outline was the predominant format for ZFF and ZTF, while oval format was the most frequent for ZOF. Median distances from ZFF to frontozygomatic and zygomaticomaxillary sutures were higher on right and left sides of the skulls, respectively (P < 0.005). Mean ZOF transverse diameter was significantly higher on the right sides of the skulls and presented positive correlation between sides (P < 0.05). No differences were observed for mean vertical diameter and distance from the ZOF to the inferolateral angle of the orbit (P > 0.05). No significant difference was found for distance from the ZTF to zygomatic arch between sides (P > 0.05), although there was a positive correlation (P < 0.05). Significant differences were found when analyzing the anatomical and morphometric aspects of ZFF, ZOF, and ZTF.

Photobiomodulation with LED and laser in repair of mandibular socket rabbit: clinical evaluation, histological, and histomorphometric.

PURPOSE: The aim of this study was to evaluate the effects of LED and low-intensity laser on the healing of rabbit dental alveoli. METHODS: A total of 18 rabbits were divided into three groups of six; all rabbits underwent surgical extraction of the first lower right premolar. Following surgery, group 1 received LED irradiation, group 2 received laser irradiation, and group 3 were untreated controls. The initial applications of LED and laser began 48 h after tooth extraction and were given perpendicularly to the dental alveoli. The three groups were clinically evaluated for 18 days in the postoperative period. At 90 days, the rabbits were euthanized and the mandibular fragments containing the healing alveoli were collected. These fragments initially underwent computed tomography scans and bone density was measured in Hounsfield units. Following this, the fragments were processed and stained with hematoxylin and eosin for histological and histomorphometric analysis. RESULTS: The results were compatible between the clinical, histological, and histomorphometric parameters evaluated. There were no statistical differences between the LED and laser groups. However, the difference of the average bone density between laser and control group was not statistically significant. CONCLUSIONS: It was found that photobiomodulation with LASER and LED presented effects. However, only the LED demonstrated a beneficial effect on the process of bone repair in the dental alveoli of rabbits.

Styloid Process of the Temporal Bone: Morphometric Analysis and Clinical Implications.

Objective. To evaluate measures of the styloid process (SP) in Brazilian dry skulls. Methods. This study involves measurements of two points (lateral end posterior views) of 15 dry skulls held by the Morphology Department, Institute of Biological Sciences of Federal University of Minas Gerais. Results. There was a large variability for the length of left and right sides (in lateral and posterior views) of the styloid process. From the lateral view of the left and right styloid, the length of the SP ranged, respectively, from 10.22 mm to 69.73 mm and from 8.30 mm to 63.77 mm. From a posterior view of the left and right sides of the skulls, the values range, respectively, from 15.57 mm to 69.51 mm and from 15.64 mm to 69.44 mm. Conclusion. We believe that this study provides additional information about the frequency of elongated SP among the Brazilian population.

The use of digital periapical radiographs to study the prevalence of alveolar domes.

PURPOSE: In the present study, we coined the term 'alveolar dome' and aimed to demonstrate the prevalence of alveolar domes through digital periapical radiographs. MATERIALS AND METHODS: This study examined 800 digital periapical radiographs in regard to the presence of alveolar domes. The periapical radiographs were acquired by a digital system using a photostimulable phosphor (PSP) plate. The χ(2) test, with a significance level of 5%, was used to compare the prevalence of alveolar domes in the maxillary posterior teeth and, considering the same teeth, to verify the difference in the prevalence of dome-shaped phenomena between the roots. RESULTS: The prevalence of alveolar domes present in the first pre-molars was statistically lower as compared to the other maxillary posterior teeth (p<0.05). No statistically significant difference was observed in the prevalence of alveolar domes between the maxillary first and second molars. Considering the maxillary first and second molars, it was observed that the palatal root presented a lower prevalence of alveolar domes when compared to the distobuccal and mesiobuccal roots (p<0.05). CONCLUSION: The present study coined the term 'alveolar dome', referring to the anatomical projection of the root into the floor of the maxillary sinus. The maxillary first and second molars presented a greater prevalence of alveolar domes, especially in the buccal roots, followed by the third molars and second pre-molars. Although the periapical radiograph is a two-dimensional method, it can provide dentists with the auxiliary information necessary to identify alveolar domes, thus improving diagnosis, planning, and treatment.

Odontogenic infections in a dental emergency care unit: Eleven-year epidemiological analysis

Aim: To evaluate medical records from patients who underwent abscess drainage due to odontogenic infections in a public hospital in the city of Belo Horizonte (Minas Gerais, Brazil) during the period of 2003 and 2013. Methods: A retrospective analysis of cases which required drainage of abscesses due to dental infections. The types of therapeutic procedures analyzed were endodontic drainage, intraoral mucosa drainage, periodontal drainage, and extraoral drainage. Results: 162,902 cases required dental assistance, and 32,352 cases required drainage of abscesses due to dental infections. The most frequent approach was endodontic drainage (21,313 procedures); the least frequent procedure was extraoral drainage (922 procedures). Conclusions: Odontogenic infection is a common clinical condition in dental clinics. It should be diagnosed and treated as quickly as possible to avoid or minimize progression to more severe cases. (AU)

Assessment of hematologic parameters before and after bimaxillary orthognathic surgery.

PURPOSE: The purpose of the study was to evaluate changes of hematologic parameters in bimaxillary surgery. METHODS: Fifty-three patients were prospectively evaluated and divided into groups based on the surgical procedure and sex (predictor variables). Hemoglobin, red blood cells, hematocrit, and platelet were the primary outcome variables, operation time the secondary outcome, and the patients' age and weight the other variables. TRIAL REGISTRATION: NCT02364765 (U.S. National Institutes of Health, clinicaltrials.gov). RESULTS: There was statistically significant difference between all hematologic parameters before and after surgery, for both men and women, and for all surgical groups. There was a positive correlation between operative time and the decrease (in %) of the hematologic parameters. Linear regression analysis suggested that the Hb values decrease 0.083 % for every minute increase in the operation time, and 0.066, 0.066, and 0.010 % for RBC, Hct, and platelet count, respectively. There was a negative correlation between weight and all hematologic parameters. Correlations between age and hematologic parameters were not statistically significant. Almost all correlations between age, weight, sex, and the surgery group and the hematologic parameters were considered as very weak. Only one patient was transfused. CONCLUSIONS: It is suggested that operation time and patient's weight play a bigger role than patient's age and sex in the decrease of hematologic parameters after bimaxillary surgery.

Zygomatic implants: a critical review of the surgical techniques.

PURPOSE: The purpose of the present study is to identify and describe the different surgical techniques for placement of zygomatic implants reported in the literature and discuss the differences between them. METHODS: An electronic search was undertaken in July 2011. The titles and abstracts from these results (n = 130) were read for identifying studies, which reported different surgical techniques for placement of zygomatic implants, which resulted in 41 articles. RESULTS: Five different surgical approaches were identified: (1) the classical approach, (2) the sinus slot technique, (3) the exteriorized approach, (4) the minimally invasive approach by the use of custom-made drill guides, and (5) the computer-aided surgical navigation system approach. When the maxilla is severely resorbed, the concavity formed by the ridge crest is small, and the original classical technique should be used. When maxillary resorption generates a large concavity, it would be better to exteriorize the zygomatic implant. The externalized technique has fewer surgical steps than the classical and sinus slot methods, is less invasive, and reduces surgical time. It is recommended that utilization of the sinus slot technique together with the CT-based drilling guide would enhance the final results. Although the technique that uses the computer-aided surgical navigation system approach may produce an improved precision in the clinical procedure, its use is expensive, prolongs the operation time, and is limited to centers that have the necessary equipment for the surgery. CONCLUSIONS: Preference for one technique over the other should take into consideration the concavity formed by the ridge crest, maxillary sinus, and region of implant insertion in the zygomatic bone.

Morphological variation in dentate and edentulous human mandibles.

PURPOSE: The aim of the study was to examine the different morphometric variations of the human mandibles, comparing between males and females in dentate and edentulous mandibles. METHODS: Eighty adult human dry mandibles were studied. Thirty-two variations were evaluated according to the presence and absence of teeth. Kolmogorov-Smirnov test was performed to evaluate the normal distribution of the morphometric variables. Levene test evaluated homoscedasticity. Student t tests and Mann-Whitney U tests, when indicated, were performed to compare each of the morphometric variables between dentate and edentulous mandibles. Statistical differences were considered when the P value was less than 0.05. RESULTS: Considerable numbers of measurements were statistically significantly different when comparing the influence of dental status on the anatomical measurements; the position and anatomical relations of the mental foramen and overall dimensions of the mandible are especially influenced. Only a few measurements were statistically significantly different in the comparison between males and females. CONCLUSIONS: The results of this research showed that the presence or absence of the teeth can alter mandibular shape and that mandibular edentulism may be associated with specific shape changes in the mandible. The dental status has a higher influence on the mandibular anatomy than the difference in gender.

A morphometric analysis of supraorbital and infraorbital foramina relative to surgical landmarks.

PURPOSE: The aim of the study was to examine the different morphometric variations of the supraorbital and infraorbital foramina of the facial skeleton on human skulls. METHODS: Eighty adult human dry skulls were studied. Measurements were made to analyze the degree of variability in the location of the supraorbital and infraorbital foramina. All measurements were done bilaterally. Variations were evaluated according to gender and side. RESULTS: There were 54 female and 26 male crania. Almost all mean measurements were longer in males than in females. A statistically significant difference was observed between the left and the right sides in 4 of 10 measurements. When comparing the morphometric measurements between left and right sides of male and female crania, 6 of 22 measurements were statistically higher in men than in women. CONCLUSIONS: The findings suggest that gender should be taken into account when the foramina studied here are to be located. The mean location of the infraorbital nerve was about 6.5 mm inferior to the inferior orbital rim (at the point where one can palpate the zygomatico-maxillary suture), about 25 mm from the midline, and about 43 mm below the supraorbital foramen in the same vertical line. Extra care should be taken during surgical dissection in the superior orbital region especially in the middle aspect of the superior orbital rim. In general, there were changes in measurements between the genders, but the ratios of these measurements with the horizontal and vertical measurements chosen remained the same between the genders.

Prevalence of enamel pearls in teeth from a human teeth bank.

Enamel pearls are anatomical structures that can bring about clinical implications if associated with the retention of plaque, in turn resulting in periodontal disease. In an attempt to avoid periodontal disease, the removal and treatment of these enamel pearls, may be a necessity in some circumstances. A total of 45,785 extracted teeth from a human teeth bank were analyzed for the presence of enamel pearls. The most prevalent anatomical location of enamel pearls was the permanent maxillary first and second molar region. An association between the prevalence of enamel pearls and dental class (P < 0.001) was observed, most frequently in the maxillary molars. In the maxillary molars, the most prevalent anatomical location of enamel pearls in the first and second molars was the furcation between the distobuccal and palatal roots. Enamel pearls are a common observation in molars in general, but are most commonly found in maxillary molars.

Accuracy evaluation of computed tomography-derived stereolithographic surgical guides in zygomatic implant placement in human cadavers.

Presurgical planning is essential to achieve esthetic and functional implants. For implant planning and placement, the association of computer-aided design (CAD) and computer-aided manufacturing (CAM) techniques furnishes some advantages regarding tridimensional determination of the patient's anatomy and fabrication of both anatomic models and surgical guides. The goal of this clinical study was to determine the angular deviations between planned and placed zygomatic implants using stereolithographic surgical guides in human cadavers. A total of 16 zygomatic implants were placed, 4 in each cadaver, with the use of stereolithographic (SLA) surgical guides generated by computed tomography (CT). A new CT scan was made after implant insertion. The angle between the long axis of the planned and actual implants was calculated. The mean angular deviation of the long axis between the planned and placed implants was 8.06 ± 6.40 (mean ± SD) for the anterior-posterior view, and 11.20 ± 9.75 (mean ± SD) for the caudal-cranial view. Use of the zygomatic implant, in the context of this protocol, should probably be reevaluated because some large deviations were noted. An implant insertion guiding system is needed because this last step is carried out manually. It is recommended that the sinus slot technique should be used together with the CT-based drilling guide to enhance final results. Further research to enhance the precision of zygomatic implant placement should be undertaken.

Anatomical variation in the position of the greater palatine foramen.

The present study measured the position of the greater palatine foramen relative to adjacent anatomical landmarks in Brazilian skulls. The perpendicular distance of the greater palatine foramen to the midline maxillary suture in Brazilian skulls was about 14 mm and the distance of greater palatine foramen to the incisive foramen was approximately 36 mm. The distance of greater palatine foramen to the posterior border of the hard palate was approximately 3 mm, and the mean angle between the midline maxillary suture and the line from the incisive foramen and the greater palatine foramen was 22.71 degrees . In almost 70% of the cases, the greater palatine foramen opened in an anterior direction. The mean palatine length was approximately 52 mm. In the greater majority of the skulls (93.81%), the greater palatine foramina were opposite or distal to the maxillary third molar. These data will be helpful in comparing these skulls to those from various other regions as well as comparing skulls of different races. It can also provide professionals with anatomical references, in order to block the maxillary division of the trigeminal nerve through the greater palatine foramen. Our results would help clinicians locate the greater palatine foramen in patients with and without upper molars.

Considerations of mandibular angle fractures during and after surgery for removal of third molars: a review of the literature.

BACKGROUND: Angle fractures are quite common considering that the angle of the mandible forms an area of lower resistance which contains a thicker upper border, a thin basilar bone, and the presence of an impacted mandibular third molar. Common complications of mandibular third molar surgery include alveolar osteitis (dry socket), secondary infection, nerve dysfunction, and hemorrhage. Reports of mandibular fracture during and after third molar removal are uncommon. PURPOSE: The purpose of this paper is to discuss the risk and predisposing factors that should be analyzed regarding the possibility of immediate and late mandibular angle fractures and their need for surgical treatment as a means through which to remove impacted molars. This study is based on a thorough review of the literature as well as on one immediate and one late mandibular angle fracture as described by the authors' own personal experience. CONCLUSIONS: The danger of an immediate jaw fracture can be avoided by means of proper instrumentation and by refraining from excessive force on the bone. The tooth should be sectioned in such a way as to minimize the extent of bone removal and force caused by instrumentation. The danger of a late jaw fracture can be avoided by precise diagnosis in cases of patients over 25 years of age, particularly men, whose tooth roots are superimposed on or adjacent to the inferior alveolar canal on a panoramic image, any local pathology and systemic disease or medications which may impair bone strength, and patients who present bruxism and are active athletes.