Exploring digital technologies used in the design and manufacture of craniofacial implant surgical guides: A scoping review.

STATEMENT OF PROBLEM: Unlike intraoral implants, digitally planned surgical templates used for guiding the ideal position of the craniofacial implants are not well established, and clear methods and guidelines for their design and construction are lacking. PURPOSE: The purpose of this scoping review was to identify the publications that used a full or partial computer-aided design and computer-aided manufacture (CAD-CAM) protocol to create a surgical guide that achieves the correct positioning of craniofacial implants to retain a silicone facial prosthesis. MATERIAL AND METHODS: A systematic search was conducted in MEDLINE/PubMed, Web of Science, Embase, and Scopus for articles published before November 2021 in the English language. Articles needed to satisfy the eligibility criterion of in vivo articles that created a surgical guide with digital technology for inserting titanium craniofacial implants to hold a silicone facial prosthesis. Articles that inserted implants in the oral cavity or upper alveolus only and articles that did not describe the structure and retention of the surgical guide were excluded. RESULTS: Ten articles were included in the review; all were clinical reports. Two of the articles used a CAD-only approach alongside a conventionally constructed surgical guide. Eight articles described applying a complete CAD-CAM protocol for the implant guides. The digital workflow varied considerably depending on the software program, design, and retention of guides. Only 1 report described a follow-up scanning protocol to verify the accuracy of the final implant positions compared with the planned positions. CONCLUSIONS: Digitally designed surgical guides can be an excellent adjunct to accurately place titanium implants in the craniofacial skeleton for support of silicone prostheses. A sound protocol for the design and retention of the surgical guides will enhance the use and accuracy of craniofacial implants in prosthetic facial rehabilitation.

Percutaneous exposure injuries amongst dental staff and students at a university dental clinic in Australia: A 6-year retrospective study.

PURPOSE/OBJECTIVES: Dental care providers are at risk of percutaneous exposure injuries (PEIs) due to the intimate nature of the patient-dentist environment and the routine use of sharp instruments. They are the most vulnerable to accidental exposure of blood-borne viruses. The aim of this study was to determine the types of PEIs sustained by staff and students at the Griffith University Dental Clinic over a 6-year period. METHODS: Data were collected regarding PEIs sustained amongst dental staff and students between 2014 and 2019. Data were obtained from the risk incident reporting system (GSafe) and the patient management Software (Titanium), and then analysed using IBM SPSS. The chi-squared tests and multinomial logistic regressions were performed with significance set at <.05. RESULTS: Over the 6-year period, there were 308 PEIs with an incidence rate of 0.109%, with 67 being needle stick injuries (0.023%). These injuries happened more often in restorative procedures, followed by local anaesthesia and oral surgery. Dental students were at a greater risk of sustaining PEIs (65.6%) when compared with professional staff (34.4%). Most common instruments included needles (21.8%), probes (20.5%) and burs (18.2%). CONCLUSION: Overall, the incidence of percutaneous injuries at the Griffith University Dental Clinic was low. The most common instruments were needles, probes and burs, and dental students were at greatest risk of sustaining injuries. Prevention of injuries by not recapping needles, immediate removal of burs from handpieces, the use of cassettes and single-use instruments has effectively decreased PEIs experienced by dental students and staff.

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).

Dental implant placement with bone augmentation in a patient who received intravenous bisphosphonate treatment for osteoporosis.

Intravenous (IV) administration of bisphosphonates has been considered an absolute contraindication for placement of dental implants, because of the increased risk of bisphosphonate-related osteonecrosis of the jaw (BRONJ). However, the evidence regarding this association originates from patients being treated for various forms of metastatic cancer. In the case reported here, a patient received a dental implant while undergoing IV treatment with zoledronic acid for osteoporosis. The authors discuss the current evidence regarding the risks of dental procedures in patients receiving IV bisphosphonates for this indication. They also evaluate important risk factors and the decision-making pathway in such cases. On the basis of existing evidence, receipt of a single IV infusion of zoledronic acid for the treatment of osteoporosis does not appear to be an absolute contraindication to implant placement.

Correlation between upper airway dimension and TMJ position in patients with sleep disordered breathing.

OBJECTIVE: The goal was to perform a 10-year retrospective study on the correlation between sleep disordered breathing (SDB) and upper airway dimensions, as well as the relation between SDB status and TMJ position. The study also examined links between airway dimensions and TMJ position. METHODS: Patients were categorized into Control (n = 28) or SDB (n = 45). Cone beam (CBCT) data was analyzed using InVivo5™. RESULTS: Although there were distinctive features within the SDB group, these did not show a correlation of significance with airway dimensions. SDB patients were more likely to have their condyles posteriorly seated. Other factors, such as presence of TMD, limited mouth opening, and pain upon palpation of masticatory muscles also significantly affected the TMJ position. Volumetric airway analysis showed links to TMJ position. CONCLUSION: SDB patients have a smaller airway volume and have a significant relationship between airway volume and TMJ position with their condyles seated more posteriorly.

Medical profile of patients referred to an Australian postgraduate oral surgery clinic.

BACKGROUND AND OBJECTIVES: Thorough knowledge of a patient's medical history and medications is necessary for providing safe oral surgery care, and may be considered a form of risk management. This study investigated the prevalence of medical conditions and medication types in patients referred to an Australian postgraduate oral surgery clinic over 2 years. MATERIALS AND METHODS: A retrospective cross-sectional study of the clinical records of 233 randomized patients referred to the Griffith University (Queensland, Australia) postgraduate oral surgery clinic in 2018 and 2019 was performed. Medical conditions and medications were counted and categorized, and descriptive statistics were generated. RESULTS: In all, 133 patients (57%) had at least one medical condition. 58% of them (77) had two or more categories of medical conditions, representing nearly a third (33.0%) of all sampled patients. The most prevalent category of medical conditions was psychiatric (25.3%), followed closely by cardiovascular (24.5%) diseases. Cardiovascular medications were the most prevalent, comprising 23.6% of all medications recorded, followed by psychotropics (18.3%). CONCLUSION: Over half of patients referred to the postgraduate oral surgery clinic had at least one systemic medical condition. Nearly a third of patients referred had at least two distinct systemic medical conditions. With an ageing population and the accompanying rise in multimorbidity globally, dental school curricula must adapt to prepare students to meet these challenges in their careers.

Relationship between craniofacial and dental arch morphology with pharyngeal airway space in adolescents.

PURPOSE: The aim of the study was to investigate a possible relationship between pharyngeal airway space, craniofacial variables, and dental arch form in adolescents grouped by sex. METHODS: This cross-sectional study included 108 adolescents aged between 12 and 17 years. Lateral cephalometric radiographs were used to analyze sagittal craniofacial variables and the pharyngeal airway space. For evaluation of the dental arch form, we used plaster models. Statistical analysis included Student's t­test and Pearson's correlation coefficient (r). RESULTS: Maxillary length was directly proportional to upper nasopharyngeal airway dimensions in males (r = 0.312, p = 0.021) and females (r = 0.310, p = 0.022). In the female group, upper oropharyngeal measurements showed an inverse correlation with a labial inclination of the upper incisors (r = -0.415, p = 0.001), protrusion of the upper incisors (r = -0.364, p = 0.006), and soft palate thickness (r = -0.27, p = 0.043). In the male group, upper nasopharynx measurements showed an inverse correlation with soft palate thickness (r = -0.277, p = 0.042). The upper arch form appeared to be related to oropharyngeal measurements in females, while the lower arch form was related to oropharyngeal dimensions in males. CONCLUSION: The findings suggest that there are sex-dependent correlations of the nasopharyngeal and oropharyngeal airway space with the sagittal craniofacial morphology and the transversal dental arch form.

A Novel Irrigation System to Reduce Heat Generation during Guided Implantology: An In Vitro Study.

The purpose of this in vitro study is to evaluate the effectiveness of incorporating a new irrigation system into a surgical guide and monitor its effect on heat generation during implant bed preparation. A total of 48 surgically guided osteotomies were performed on 12 bovine ribs divided into 4 groups, using different irrigation techniques: Group A (test) had entry and exit channels incorporated into the guide; Group B had a similar design with an entry channel only; Group C had conventional external irrigation; and Group D (control) had no irrigation. Heat generation during the osteotomies was measured using thermocouples placed at a depth of 2 mm and 6 mm. The lowest mean temperature was observed in Group A (22.1 °C at 2 mm and 21.4 °C at 6 mm), which was statistically significant when compared with Groups C and D (p < 0.001). Group A showed a lower mean temperature compared with Group B as well; however, it was statistically significant only at 6 mm depth (p < 0.05). In conclusion, the proposed surgical guide has significantly reduced heat generation during implant osteotomy compared to conventional external irrigation. The integration of an exit cooling channel can resolve limitations found in previously designed surgical guides such as debris blockage and can be easily incorporated into computer designing and 3D printing software.

A Novel Apparatus to Standardise the Polishing Protocol to Achieve Different Roughness of Titanium and Zirconia Disc Surfaces.

PURPOSE: This study aimed to propose and evaluate standardised polishing protocols for in vitro experiment using a custom-made apparatus under controlled force to create consistent surface roughness on titanium and zirconia disks. METHODS: A total of 160 discs were manufactured with a diameter of 10mm, 80 titanium (Ti), and 80 zirconium oxide (Zr). Specimens were categorised into 2 groups: controlled force (CF) and without controlled force (WCF). Specimens in the CF group were polished with a custom apparatus incorporating a tension gauge on the Ti and Zr disc surfaces to achieve consistent roughness. The WCF was polished without the use of a tension gauge. Each group had 4 subgroups (10 disks in each): control/machined (C) with no polishing, rough (R), smooth (S) and very smooth (VS). The subgroups were processed using a sequence of diamond-impregnated polishing burs and polishing paste. RESULTS: CF group showed consistent surface roughness and a gradual decrease in surface roughness. Control (Ra=6.5±0.03µm) in Ti and (Ra=5.4±0.04µm) in Zr; R (Ra=3.5± 0.06µm) in Ti and (Ra=3.2± 0.07 µm) in Zr; S (Ra=1.5±0.04µm) in Ti and (Ra=1.1±006µm) in Zr; VS (Ra=0.05± 0.002µm) in Ti and (Ra=0.02±0.005µm) in Zr. There were significant differences for R, S, and SV under CF and WCF in Ti and Zr surfaces. CONCLUSION: The specimens polished under control force produced significantly more uniform surface roughness than those polished without controlled force and were produced with a higher degree of consistency.

Resorbable GBR Scaffolds in Oral and Maxillofacial Tissue Engineering: Design, Fabrication, and Applications.

Guided bone regeneration (GBR) is a promising technique in bone tissue engineering that aims to replace lost or injured bone using resorbable scaffolds. The promotion of osteoblast adhesion, migration, and proliferation is greatly aided by GBR materials, and surface changes are critical in imitating the natural bone structure to improve cellular responses. Moreover, the interactions between bioresponsive scaffolds, growth factors (GFs), immune cells, and stromal progenitor cells are essential in promoting bone regeneration. This literature review comprehensively discusses various aspects of resorbable scaffolds in bone tissue engineering, encompassing scaffold design, materials, fabrication techniques, and advanced manufacturing methods, including three-dimensional printing. In addition, this review explores surface modifications to replicate native bone structures and their impact on cellular responses. Moreover, the mechanisms of bone regeneration are described, providing information on how immune cells, GFs, and bioresponsive scaffolds orchestrate tissue healing. Practical applications in clinical settings are presented to underscore the importance of these principles in promoting tissue integration, healing, and regeneration. Furthermore, this literature review delves into emerging areas of metamaterials and artificial intelligence applications in tissue engineering and regenerative medicine. These interdisciplinary approaches hold immense promise for furthering bone tissue engineering and improving therapeutic outcomes, leading to enhanced patient well-being. The potential of combining material science, advanced manufacturing, and cellular biology is showcased as a pathway to advance bone tissue engineering, addressing a variety of clinical needs and challenges. By providing this comprehensive narrative, a detailed, up-to-date account of resorbable scaffolds' role in bone tissue engineering and their transformative potential is offered.

Oropharyngeal complex differences related to sex and occlusal factors in adolescents aged 12-17 years.

OBJECTIVE: To investigate oropharyngeal complex differences related to sex and occlusal factors in adolescents. METHODS: A cross-sectional study was conducted with 108 patients aged 12-17 years. The oropharyngeal complex was evaluated by imaging exams. Occlusal variables included molar relationship, facial growth pattern, maxilla shape, tooth loss, anterior crossbite, and anterior open bite. Statistical analysis included independent t-test, Mann-Whitney, ANOVA, and Kruskal-Wallis tests. The significance level was 5%. RESULTS: There were increases of the tongue measurement (p = 0.026) and the hyoid approach at the base of the mandible among boys (p = 0.016) and the distance from the hyoid at the base of the mandible among girls (p = 0.039). There was shortening of the soft palate measurements (p = 0.003 and p = 0.007) and tongue (p = 0.018) among adolescents with an anterior crossbite. CONCLUSION: Findings suggest sex, age, and anterior crossbite can be related to oropharyngeal morphology.

Frequency and characteristics of medical emergencies in an Australian dental school: A retrospective study.

PURPOSE/OBJECTIVES: The frequency of medical emergencies in a dental setting is relatively low. However, most dental treatment occurs outside of a hospital setting; thus the time to respond to a life-threatening situation is crucial. The aim of this study was to determine the frequency and characteristics of medical emergencies that occurred at the Griffith University Dental Clinic over a 6-year period. METHODS: Data involving medical emergencies was collected at a dental school between January 2014 and December 2019. Data was obtained from the risk incident reporting system (GSafe), and descriptive statistics were analyzed using IBM SPSS. RESULTS: The frequency of medical emergencies in a dental setting over the 6-year retrospective period based on the number of dental services provided was 0.037% (n = 108). The three most common medical emergencies were syncope (25.0%), hypoglycemia (16.7%), and foreign body ingestion (13.9%). These happened more often during dental extractions (26.9%), followed by local anesthesia (16.7%) and restorative procedures (13.0%). A larger portion of these incidents occurred during dental treatment (62.0%) as opposed to before (12.0%) or after (26.0%). Most medical emergencies happened within the dental student clinic (72.2%) followed by the dental waiting room (19.5%) and dental private clinic (8.3%). CONCLUSION: Overall, the number of medical emergencies at the Griffith University Dental Clinic was low. The most common medical emergencies were syncope, hypoglycemia, and foreign body ingestion. Dental education in preventative strategies and training in basic life support is necessary to ensure dental practitioners can manage the acute deterioration of a patient promptly.

A systematic review on neutrophils interactions with titanium and zirconia surfaces: Evidence from in vitro studies.

OBJECTIVES: This systematic review aimed to assess in vitro studies that evaluated neutrophil interactions with different roughness levels in titanium and zirconia implant surfaces. MATERIAL AND METHODS: An electronic search for literature was conducted on PubMed, Embase, Scopus, and Web of Science and a total of 14 studies were included. Neutrophil responses were assessed based on adhesion, cell number, surface coverage, cell structure, cytokine secretion, reactive oxygen species (ROS) production, neutrophil activation, receptor expression, and neutrophil extracellular traps (NETs) release. The method of assessing the risk of bias was done using the toxicological data reliability assessment tool (TOXRTOOL). RESULTS: Ten studies have identified a significant increase in neutrophil functions, such as surface coverage, cell adhesion, ROS production, and NETs released when interacting with rough titanium surfaces. Moreover, neutrophil interaction with rough-hydrophilic surfaces seems to produce less proinflammatory cytokines and ROS when compared to naive smooth and rough titanium surfaces. Regarding membrane receptor expression, two studies have reported that the FcγIII receptor (CD16) is responsible for initial neutrophil adhesion to hydrophilic titanium surfaces. Only one study compared neutrophil interaction with titanium alloy and zirconia toughened alumina surfaces and reported no significant differences in neutrophil cell count, activation, receptor expression, and death. CONCLUSIONS: There are not enough studies to conclude neutrophil interactions with titanium and zirconia surfaces. However, different topographic modifications such as roughness and hydrophilicity might influence neutrophil interactions with titanium implant surfaces.

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.

Analgesia and side effects of codeine phosphate associated with paracetamol vs. paracetamol after the extraction of mandibular third molars: a randomized double-blind clinical trial using the split-mouth model.

PURPOSE: To assess the analgesia and side effects of codeine phosphate associated with paracetamol (test medication) as compared to paracetamol (control medication) after the extraction of impacted mandibular third molars. MATERIALS AND METHODS: Forty-seven patients removed the right and left impacted mandibular third molars. After one surgery, patients took the test medication and after the other surgery, they took the control medication. Patients with exacerbated pain were prescribed to use the rescue medication instead of the medication initially administered and were included in the rescue group. They were evaluated for 7 days postoperatively, and the mean score of the visual analogue scale (VAS) of pain between test and control medications was assessed by the Poisson distribution. The side effects of these medications were assessed by the patient's complaints. A P value of < .05 was considered to be statistically significant. RESULTS: The mean score of the VAS of pain was not statistically different between test and control medications in the non-rescue group, but it was significantly greater in patients previously using paracetamol in the rescue group. The most common side effects reported in both groups, predominantly in patients using the test medication, were drowsiness, dizziness, and nausea. CONCLUSION: The use of codeine phosphate associated with paracetamol after the extraction of impacted mandibular third molars is a better choice to control the postoperative pain rather than paracetamol, but with more side effects, which are clinically acceptable.

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.

Quantitative Assessment of the Efficacy of Two Different Single-file Systems in Reducing the Bacterial load in Oval-Shaped Canals: A Clinical Study.

INTRODUCTION: This randomized clinical study compared the in vivo antibacterial efficacy of Reciproc Blue (RB), XP-endo Shaper (XP-S), and XP-endo Shaper associated with XP-endo Finisher (XP-F) systems in infected oval-shaped root canals with primary apical periodontitis. METHODS: In this study, 28 human teeth with a single root and a single canal were randomly assigned to 2 groups according to the instrumentation technique: group 1, RB (n = 14) and group 2, XP-endo (XP-S and XP-F, n = 14). The single-rooted teeth were prepared by reciprocating and rotary nickel-titanium instruments with 5.25% sodium hypochlorite irrigation. Samples were collected from the canal at the baseline (S1), after chemomechanical preparation (S2), and after XP-F instrumentation (S3). The DNA extracts were subjected to quantitative analysis for total bacterial counts by quantitative real-time polymerase chain reaction. The data were analyzed using the analysis of variance test, and the level of significance was set at 5%. RESULTS: All samples tested positive for the presence of bacteria at baseline, and the bacterial counts substantially reduced after treatment procedures (P < .01). The results showed no statistical difference between RB and XP-S instrumentation with respect to the bacterial reduction (P > .05). A marked bacterial reduction was observed after the use of the XP-F instrument (P < .01). CONCLUSIONS: The XP-S and RB systems sharply reduced the bacterial load in oval-shaped root canals with primary apical periodontitis. XP-F used as a supplementary instrument to chemomechanical preparation promoted a significantly higher bacterial reduction.

The effect of ultrasound on angiogenesis: an in vivo study using the chick chorioallantoic membrane.

PURPOSE: Ultrasound therapy induces clinical healing of irradiated avascular mandibular bone and fractures. In vitro ultrasound in tissue culture has been shown to stimulate bone formation synthesis and bone remodeling factors and to stimulate osteoblast proliferation. Therefore, the aim of the present study was to investigate the effect of short-wave (1-MHz) and long-wave (45-kHz) ultrasound on the vascularity of the chorioallantoic membrane (CAM) of a fertilized egg. MATERIALS AND METHODS: The nature of the angiogenic effect was investigated using the CAM of a fertilized egg by: (1) application of sonicated fibroblast media incorporated into methylcellulose disks onto the CAM and (2) direct application of the ultrasound, using both long-wave (45-kHz) and short-wave (1-MHz) frequencies at a range of intensities, to the surface of the egg. Angiogenesis was assessed quantitatively by three independent observers. RESULTS: Both ultrasound methods showed evidence of an angiogenic effect compared to controls. The most effective results were seen with direct application of a 45-kHz wave at an intensity of 15 mW/cm(2) and indirect application of the media of fibroblasts ultrasonicated at 1 MHz with an intensity of 0.4 W/cm(2). CONCLUSION: This model confirms that ultrasound can induce neoangiogenesis in vivo.

Bone Invasive Properties of Oral Squamous Cell Carcinoma and its Interactions with Alveolar Bone Cells: An In Vitro Study.

BACKGROUND: Co-culture of cancer cells with alveolar bone cells could modulate bone invasion and destructions. However, the mechanisms of interaction between oral squamous cell carcinoma (OSCC) and bone cells remain unclear. OBJECTIVE: The aim of this study is to analyse the direct and indirect effects of OSCC cells in the stimulation of osteolytic activity and bone invasion. METHODS: Direct co-culture was achieved by culturing OSCC (TCA8113) with a primary alveolar bone cell line. In the indirect co-culture, the supernatant of TCA8113 cells was collected to culture the alveolar bone cells. To assess the bone invasion properties, in vitro assays were performed. RESULTS: The proliferation of co-cultured cancer cells was significantly (p<0.05) higher in comparison to the monolayer control cells. However, the proliferation rates were not significantly different between direct and indirect co-cultured cells with indirect co-cultured cells proliferated slightly more than the direct co-cultured cells. Invasion and migration capacities of co-cultured OSCC and alveolar bone cells enhanced significantly (p<0.05) when compared to that of control monolayer counterparts. Most importantly, we noted that OSCC cells directly co-cultured with alveolar bone cells stimulated pronounced bone collagen destruction. In addition, stem cells and epithelialmesenchymal transition markers have shown significant changes in their expression in co-cultured cells. CONCLUSION: In conclusion, the findings of this study highlight the importance of the interaction of alveolar bone cells and OSCC cells in co-culture setting in the pathogenesis of bone invasion. This may help in the development of potential future biotherapies for bone invasion in OSCC.

Advanced osteosarcoma of the maxilla: a case report.

Osteosarcomas are primary malignant bone tumours in which mesenchymal cells produce osteoid. It is generally the most common malignant bone neoplasm, although lesions of the jaw are uncommon. Osteosarcoma of the jaw (JOS) presents a lower incidence of metastasis and a better prognosis than osteosarcoma of the long bones. However, patients with JOS can exhibit advanced tumours, mainly when early diagnosis is not performed. This article reports on a case of an advanced osteosarcoma of the maxilla. A 38-year-old woman was referred for evaluation and treatment of recurrent fibrous dysplasia of the facial bones. The patient related that she had been diagnosed with fibrous dysplasia four years earlier and, since the first diagnosis, she was submitted to four surgical interventions, all followed by recurrences. The main clinical findings were redness and swelling of the facial skin, upper lip ulceration, and hard palate swelling. Computed tomography showed a large hyperdense mass in right maxilla extending to right orbit and left maxillary sinus. An incisional biopsy was performed and microscopic examination showed areas of osteoid and chondroid formation surrounded by a cellular stroma. The diagnosis of osteosarcoma was established and the patient was recommended for oncologic treatment. Unfortunately, she died six months after the diagnosis due to uncontrollable local spread.