Virtual planning, guided surgery, and digital prosthodontics in the treatment of extended mandible chondrosarcoma.

Chondrosarcoma is among the most common primary bone tumors in adults. In the mandible, chondrosarcoma is a very uncommon malignant cartilage-producing tumor. This case report shows how virtual planning combined with other digital technologies may improve masticatory function rehabilitation in patients with enlarged mandibular chondrosarcoma. The present study reports a case of a 52-year-old male patient who was initially diagnosed with a mandible chondroma, which was successfully excised with no evidence of malignant transformation. Nevertheless, the patient's symptoms recurred after 10 years, and a subsequent diagnosis of mandible chondrosarcoma was established, prompting the need for subtotal mandible resection and reconstruction with a fibula-free flap. Following a healing period, the patient underwent dental implant surgery to restore the mandibular dental arch, which was performed utilizing computer-aided design and computer-aided manufacturing technology, with fully guided implant placement facilitated by virtual planning. In this case report, the implant position data merging process is described from the digital impression and control model to ensure optimal passive fit of the full-arch zirconia prosthesis and discuss the importance of occlusal adjustments to avoid technical and biological complications. Virtual planning and digital technologies are crucial for the effective management of mandibular defects, allowing for accurate treatment and complete restoration of mandibular function. Their use leads to improved patient outcomes and quality of life. As technology advances, their importance in treating complex medical conditions is only expected to grow.

Influence of Kennedy class and number of implants on the accuracy of dynamic implant navigation: An in vitro study using an X-ray free evaluation methodology.

OBJECTIVES: The aim of this in vitro study was to evaluate the accuracy of fully guided dynamic implant navigation surgery in Kennedy I, II, and III class dental arch defects with two different implant designs, using an X-ray free evaluation method. METHODS: Polyurethane resin maxillary models simulated posterior edentulous defects. Four cone beam computed tomography (CBCT) scans and four intraoral (IOS) scans were obtained for each model and a digital wax-up with the correct implant positions was made. The accuracy of implant positions was evaluated using an IOS-based X-ray-free method (3Shape). Four deviation characteristics were evaluated: insertion point, depth deviation, horizontal and angle deviation. RESULTS: The insertion point deviation measures ranged from 0.19 mm to 1.71 mm. Depth (s) and (u) deviations ranged from -1.47 mm to 0.74 mm and from 0.02 mm to 1.47 mm, respectively. Horizontal deviation ranged from 0.09 mm to 1.37 mm. CONCLUSIONS: There is a tendency of a decreasing insertion point deviation for an increasing number and distribution area of the teeth (increasing Kennedy class number). Kennedy class II and distal implant position had the most influence for the higher deviations. CLINICAL SIGNIFICANCE: Dynamic implant guidance provides accurate spacing, angulation, depth and position of the implants. It is important to understand how the number of missing teeth and implant design could influence the accuracy of dynamic implant navigation. Thus, it is important to evaluate factors influencing the accuracy of dynamic systems by using a X-ray-free post-operative method and to overcome the limitations of providing multiple CBCT scans.

Importance of education on infection control and on the hand skin health of dental personnel.

BACKGROUND: Hand hygiene plays a significant role in infection control, yet it is performed correctly only 40% of the time. The daily use of soap, disinfectants and gloves can also affect hand skin health. Periodical educational interventions regarding hand hygiene can improve infection control. OBJECTIVES: The current study aimed to identify the existing hand hygiene practices applied by dental personnel, to evaluate knowledge about infection control, to determine the adverse effects of hand hygiene on the skin, and to assess the effectiveness of the educational interventions concerning these topics. MATERIAL AND METHODS: This study was carried out at the Vilnius University Hospital Zalgiris Clinic, Lithuania. At the 1st stage, data was collected by using a self-administered questionnaire. At the 2nd stage, dental personnel underwent an educational intervention and the surveys were redistributed to determine any changes in the level of knowledge. RESULTS: In most cases, dental workers performed hand hygiene when it was needed. The proper method was selected by 53.4% on average. The main mistakes were the excessive use of soap and only occasional use of a disinfectant. The reported hand skin side effects included dryness (68.8%) and fissures (37.5%). Only half (50.5%) of the staff regularly used emollients. After the educational intervention, there was a 24.9% improvement in hand hygiene compliance. CONCLUSIONS: The correct procedure for hand hygiene was reported by half of the participants. Washing hands with soap was the preferable choice, while alcohol-based hand rub (ABHR) was avoided. Skin problems were reported by more than 70% of the respondents. Training had a positive impact on the hand hygiene knowledge of the dental personnel.

Model-free digital workflow and immediate functional loading of implant-supported monolithic glass-ceramic crowns: A case series.

OBJECTIVES: The aim of this study was to evaluate surgical and prosthetic outcomes of immediate functional loading of implants with glass-ceramic screw-retained single crowns. METHODS: A total of 22 implants were placed. Within 24 h, functional full-contour glass ceramic crowns were delivered to patients. The amount of attached gingiva, Simplified Oral Hygiene Index Score, bleeding on probing, time after extraction, bone type, implant size, soft tissue thickness, primary stability, a general fit of the restoration, occlusal and proximal contacts were recorded. Restorations were followed-up at 1, 3, and 6 months tracking marginal bone loss (MBL), noting changes in occlusal and interproximal contacts, checking other possible complications. RESULTS: One implant failed and was removed after 4 weeks (95.5% survival rate). The rest of the implants and crowns functioned with no complications during the follow-up period of 6 months. Factors such as time after extraction, bone type, implant size, soft tissue thickness, and primary stability recorded in Ncm and implant stability quotient (ISQ) values, were not associated with MBL (p<0.05). Mean MBL was found to be 0.3 mm (standard deviation = 0.42) mesially and 0.4 mm (standard deviation = 0.66) distally. One distal and one mesial proximal contact were found to be missing at the 6-month check-up appointment. CONCLUSIONS: Within the limits of this study, fully digital workflow without a 3D printed model could be successfully employed for immediate functional loading with single-unit implant-supported crowns. Further studies are needed to obtain long-term results with a larger sample of patients. CLINICAL SIGNIFICANCE: Model-free digital workflow and immediate functional loading of implant-supported monolithic glass-ceramic crown might be viable option to restore a single tooth defect.

Dental pulp stem cell-derived extracellular matrix: autologous tool boosting bone regeneration.

BACKGROUND AIMS: To facilitate artificial bone construct integration into a patient's body, scaffolds are enriched with different biologically active molecules. Among various scaffold decoration techniques, coating surfaces with cell-derived extracellular matrix (ECM) is a rapidly growing field of research. In this study, for the first time, this technology was applied using primary dental pulp stem cells (DPSCs) and tested for use in artificial bone tissue construction. METHODS: Rat DPSCs were grown on three-dimensional-printed porous polylactic acid scaffolds for 7 days. After the predetermined time, samples were decellularized, and the remaining ECM detailed proteomic analysis was performed. Further, DPSC-secreated ECM impact to mesenchymal stromal cells (MSC) behaviour as well as its role in osteoregeneration induction were analysed. RESULTS: It was identified that DPSC-specific ECM protein network ornamenting surface-enhanced MSC attachment, migration and proliferation and even promoted spontaneous stem cell osteogenesis. This protein network also demonstrated angiogenic properties and did not stimulate MSCs to secrete molecules associated with scaffold rejection. With regard to bone defects, DPSC-derived ECM recruited endogenous stem cells, initiating the bone self-healing process. Thus, the DPSC-secreted ECM network was able to significantly enhance artificial bone construct integration and induce successful tissue regeneration. CONCLUSIONS: DPSC-derived ECM can be a perfect tool for decoration of various biomaterials in the context of bone tissue engineering.

In vitro comparison of 3D printed polylactic acid/hydroxyapatite and polylactic acid/bioglass composite scaffolds: Insights into materials for bone regeneration.

3D printing of polylactic acid (PLA) and hydroxyapatite (HA) or bioglass (BG) bioceramics composites is the most promising technique for artificial bone construction. However, HA and BG have different chemical composition as well as different bone regeneration inducing mechanisms. Thus, it is important to compare differentiation processes induced by 3D printed PLA + HA and PLA + BG scaffolds in order to evaluate the strongest osteoconductive and osteoinductive properties possessing bioceramics. In this study, we analysed porous PLA + HA (10%) and PLA + BG (10%) composites' effect on rat's dental pulp stem cells fate in vitro. Obtained results indicated, that PLA + BG scaffolds lead to weaker cell adhesion and proliferation than PLA + HA. Nevertheless, osteoinductive and other biofriendly properties were more pronounced by PLA + BG composites. Overall, the results showed a strong advantage of bioceramic BG against HA, thus, 3D printed PLA + BG composite scaffolds could be a perspective component for patient-specific, cheaper and faster artificial bone tissue production.

Assessment of the morphology and dimensional accuracy of 3D printed PLA and PLA/HAp scaffolds.

INTRODUCTION: In complex clinical conditions when physiological bone regeneration is insufficient, there is a need to develop synthetic material-based scaffolds. The morphologic properties of porous scaffolds are of crucial importance. The dimensional accuracy of 3D printed scaffolds can be affected by a variety of factors. MATERIALS AND METHODS: Three groups of 3D printed scaffolds were investigated: PLA1 (pure polylactic acid) printed with an FDM Ultimaker Original printer, PLA2 and composite PLA/hydroxyapatite (PLA/HAp) scaffolds printed with a Pharaoh XD 20. PLA/HAp filament was created with hot-melt extrusion (HME) equipment. The morphology of the prepared scaffolds was investigated with SEM, micro-CT and superimposition techniques, gravimetric and liquid displacement methods. RESULTS: Layer heights of PLA1 scaffolds varied the most. PLA1 scaffold volume statistically significantly differed from PLA2 (p < 0.001) and PLA/HAp (p < 0.01) groups. Filament composition had no effect on the volumes of the scaffolds printed with the Pharaoh XD 20 printer (p > 0.05). The total porosity of printed PLA/HAp scaffolds deviated the least from the original STL model. CONCLUSIONS: This study showed that PLA/10% HAp filament fabricated with HME and printed with FFF 3D printer produced equal or even better accuracy of printed scaffolds than scaffolds printed with pure PLA filament. Further research is needed to analyze the effect of HAp on 3D scaffold morphology, accuracy, mechanical and biologic properties.

The effect of larger than cell diameter polylactic acid surface patterns on osteogenic differentiation of rat dental pulp stem cells.

Topography of the scaffold is one of the most important factors defining the quality of artificial bone. However, the production of precise micro- and nano-structured scaffolds, which is known to enhance osteogenic differentiation, is expensive and time-consuming. Meanwhile, little is known about macro-patterns (larger than cell diameter) effect on cell fate, while this kind of structures would significantly facilitate the manufacturing of artificial skeleton. Therefore, this research is focused on polylactic acid scaffold's macro-pattern impact on rat's dental pulp stem cells (DPSCs) morphology, proliferation, and osteogenic differentiation. For this study, two types of scaffolds were 3D printed: wavy and porous. Wavy scaffolds consisted of 188 µm wide joined threads, meaning that cells might have been curved on the filament as well as compressed in the groove. Porous scaffolds were designed to avoid groove formation and consisted of 500 µm threads, arranged in the woodpile manner, forming 300 µm diameter pores. We found that both macro-surfaces influenced DPSC morphology compared to control. As a consequence, enhanced DPSC proliferation and increased osteogenic differentiation potential was registered in cells grown on these scaffolds. Finally, our results showed that the construction of an artificial bone did not necessarily require the precise structuring of the scaffold, because both types of macro-topographic PLA scaffolds were sufficient enough to induce spontaneous DPSC osteogenic differentiation. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 174-186, 2019.

Conservative management of large mandibular dentigerous cysts with a novel approach for follow up: Two case reports.

BACKGROUND: Dentigerous cysts are odontogenic cysts of the jaws accounting for approximately 24% of all epithelium-lined jaw cysts. Rarely, these cysts can become extremely large causing additional symptoms, while challenging treatment. This article represents a novel approach for radiological treatment follow up of large dentigerous cysts. MATERIAL AND METHODS: Dentigerous cysts were treated by marsupialization, using dedicated obturators and enucleation of the cyst afterwards. Teeth vitality in the lesion was regularly assessed by laser doppler flowmetry, follow-up of lesion regression was accomplished using semi-automatic radiographic analysis of bone healing quantification. RESULTS: Cystic marsupialization by means of the obturator resulted in a number of advantages compared to a conventional approach: lower risk of spontaneous fracture of the mandible, anatomical structure preservation, mandibular canal identification and preservation of tooth vitality as measured by intraoral laser doppler flowmetry. Notwithstanding that a 1-year follow-up panoramic image could not visualize a remnant bone defect nor cystic lesion recurrence, 3D-CBCT based semi-automated bone quantification could only demonstrate an increase of 46% of mineralized bone volume one year after surgery. Bone healing typically occurred starting from the periphery of the original lesion towards the inner core. CONCLUSIONS: The presently reported cystic marsupialization was useful as a preliminary treatment for subsequent enucleation. 3-D CBCT based objective quantification of the bone volume and healing can provide new insights in lesion healing in general and more particular in the outcome of specific diagnostic and therapeutic challenges.

Prevalence and etiology of midfacial fractures: a study of 799 cases.

BACKGROUND AND OBJECTIVE: The prevalence and etiology of midfacial fractures varies among countries. Until now, knowledge about such type of injuries in the region of the Baltic countries was rather scarce. The purpose of the study was to analyze the prevalence, etiology and localization of midfacial fractures treated at the Vilnius University Hospital Zalgiris Clinic, Vilnius, Lithuania. MATERIALS AND METHODS: The medical records of patients treated for midfacial fractures during the period January 2005 to December 2010 were analyzed for gender, age distribution, frequency and type of injury, cause of fractures, consciousness status and alcohol abuse during trauma. RESULTS: The records of 799 patients were analyzed. The male-to-female ratio was 4.4:1. The mean age of the patients was 33.16±14.0 years (min 1, max 87). As much as 68.8% of injuries were zygomatic fractures, 27.9% were maxillary, and 3.3% were isolated orbital floor fractures. The most frequent causes for injury were interpersonal violence (64%), followed by falls (16.3%) and traffic accidents (8.3%). Most midfacial fractures (65.3%) occurred between April and October (P<0.05), on weekends (58.2%; P<0.05) and at night (62.0%; P<0.05). In 14%, trauma reports indicated the abuse of alcohol. More often such persons received more than one midfacial bone fracture (P<0.05) concurrently. CONCLUSIONS: This study revealed that the main cause of midfacial fractures was assault. Male patients, aged 15-34 years, more often sustain midfacial fractures. Preventive health care programs should seek measures in the reduction of aggression and violence in close future involving family, school and community institutions.