Structural and ultrastructural analyses of bone regeneration in rabbit cranial osteotomy: Piezosurgery versus traditional osteotomes

Comparative Histopathological Analysis of Nasal Osteotomy Techniques in a Rabbit Model

Objective: Nasal osteotomy is a crucial step in rhinoplasty, explicitly addressing the open roof deformity in nasal bones. This study aimed to assess and compare the recovery patterns associated with 4 distinct osteotomy techniques in a rabbit model. Materials and Methods: Twenty white New Zealand rabbits weighing 2.5 to 3.0 kg were included in the study. Median osteotomies were performed on the left side using piezosurgery and on the right side using an oscillating micro-saw. Additionally, internal osteotomy was executed on the right side and external osteotomy on the left side, both performed with a chisel across all rabbits. Ten rabbits were sacrificed on the 7th day, while the remaining 10 were sacrificed on the 15th day for subsequent histological examination. The granulation tissue formation (GTF), vascularization, inflammation, collagen fibril content, osteotomy gap width, and new bone formation were evaluated in hematoxylin and eosin and Masson's trichrome-stained sections. Results: On the 7th day, piezosurgery demonstrated statistically-significant advantages in terms of GTF, neovascularization, and collagen fibril quantity when compared to the oscillating micro-saw (P < .05). Furthermore, a statistically-significant difference was observed among the groups concerning the distribution of connective tissue organization between the 7th and 15th days (P < .05). Conclusions: This study's findings unequivocally establish that bone healing after osteotomy with piezosurgery surpasses that achieved with an oscillating micro-saw in this rabbit model.

Minimizing Invasiveness in Neurosurgical Osteotomies: A Comparative Histomorphometric Study of Piezoelectric Craniotomy versus High-Speed Drill

BACKGROUND

Piezoelectric bone cutting has gained popularity in neurosurgical osteotomies due to perceived lower trauma compared to rotary instruments. However, histological confirmation of its decreased aggressiveness is lacking, hindering conclusive proof. This study compares the bony and neuro-meningeal invasiveness of piezoelectric craniotomy with high-speed drill techniques.

METHODS

Histological data from 21 sheep undergoing piezoelectric craniotomy and 19 sheep subjected to high-speed electric drill craniotomy were compared. Piezoelectric craniotomy utilized a 0.35 mm micro saw titanium nitride coated. Outcome parameters included the detection of the "smear layer," average osteoblast count per high-power field, and residual bone matrix for bony invasiveness assessment. Parameters for meningeal and brain parenchymal invasiveness included pachymeningeal and leptomeningeal injury, gliosis, and histiocytic infiltration. Statistical significance was determined at P < 0.05.

RESULTS

Results showed the Piezo group had fewer frequent smear layers (P <0.001), higher residual bone matrix (P < 0.05), and greater osteoblast counts per high-power field (P < 0.05). Additionally, the Piezo group exhibited lower rates of leptomeningeal injury, cerebral gliosis, and histiocytic infiltration (P < 0.05).

CONCLUSIONS

Piezoelectric craniotomy preserves residual osteoblast viability and leptomeningeal integrity while demonstrating lower rates of thermally induced gliosis and histiocytic infiltration compared to high-speed drills. This suggests the piezoelectric osteotome's minimal invasiveness in bone, meningeal, and brain tissue.

Impact of Different Osteotomy Techniques on Bone Reserve in the Osteotomy Line in Sagittal Split Osteotomy: Experimental In Vitro Study in Caprine Mandible Model

OBJECTIVE

The objective of this study was to investigate of the effect of piezzo and conventional osteotomy techniques on bone reserve in the osteotomy line and comminuted fracture ratios that is able to compromise bone to bone contact negatively.

METHODS

Bilateral sagittal split ramus osteotomy was performed on 12 fresh male Thracian curly caprine mandible. In the first group (n: 12) osteotomies were performed with piezzo device. In the second group (n: 12) osteotomies were performed with micromotor and manual osteotomes. Operative time was measured. The number of comminuted fractures, length and width of the osteotomy, and the space between the osteotomy lines was evaluated from 3-dimensional computed tomography scans.

RESULTS

The mean value of procedure duration was 320.4±10.76 seconds for piezo osteotomy and 238.8±8.29 seconds for conventional micromotor ( P <0.0001). Number of comminuted fractures was 1.41±1.3 in piezoelectric group, 1.5±1.3 in conventional group and the difference was not statistically significant (p: 0,88). Osteotomy lengths and widths were 35.58±5.2, 2.196±1.9 and 36.23±5.05, 2.27±1.85 in the piezzo and conventional groups, respectively. (p lengths :0,75; p widths :0,92) The volume of the bony interface between the distal and proximal segments of the mandible after osteotomy was 166.3±184.2 mm 3 in the piezzo group and 163.5±129.3 mm 3 in the conventional group (p: 0,96).

CONCLUSION

The piezo surgery and the conventional osteotomy were found to be similar in terms of the gap between the distal and proximal mandible and the number of comminuted fractures. The duration to perform the conventional osteotomy was found to be shorter than the piezo surgery.

In-vivo evaluations of bone regenerative potential of two novel bioactive glasses

Due to the aging of population, materials able to repair damaged tissues are needed. Among others, bioactive glasses (BGs) have attracted a lot of interest due to their outstanding properties both for hard and soft tissues. Here, for the first time, two new BGs, which gave very promising results in preliminary in vitro-tests, were implanted in animals in order to evaluate their regenerative potential. The new BGs, named BGMS10 and Bio_MS and containing specific therapeutic ions, were produced in granules and implanted in rabbits' femurs for up to 60 days, to test their biocompatibility and osteoconduction. Additionally, granules of 45S5 Bioglass® were employed and used as a standard reference for comparison. The results showed that, after 30 days, the two novel BGs and 45S5 displayed a similar behavior, in terms of bone amount, thickness of new bone trabeculae and affinity index. On the contrary, after 60 days, 45S5 granules were mainly surrounded by wide and scattered bone trabeculae, separated by large amounts of soft tissue, while in BGMS10 and Bio_MS the trabeculae were thin and uniformly distributed around the BG granules. This latter scenario could be considered as more advantageous, since the features of the two novel BG granules allowed for the neo-formation of a uniformly distributed bony trabeculae, predictive of more favorable mechanical behavior, compared to the less uniform coarse trabeculae, separated by large areas of soft tissue in 45S5 granules. Thus, BGMS10 and Bio_MS could be considered suitable products for tissue regeneration in the orthopedic and dental fields.

Effect of drill quality on biological damage in bone drilling

Bone drilling is a universal procedure in orthopaedics for fracture fixation, installing implants, or reconstructive surgery. Surgical drills are subjected to wear caused by their repeated use, thermal fatigue, irrigation with saline solution, and sterilization process. Wear of the cutting edges of a drill bit (worn drill) is detrimental for bone tissues and can seriously affect its performance. The aim of this study is to move closer to minimally invasive surgical procedures in bones by investigating the effect of wear of surgical drill bits on their performance. The surface quality of the drill was found to influence the bone temperature, the axial force, the torque and the extent of biological damage around the drilling region. Worn drill produced heat above the threshold level related to thermal necrosis at a depth equal to the wall thickness of an adult human bone. Statistical analysis showed that a sharp drill bit, in combination with a medium drilling speed and drilling at shallow depth, was favourable for safe drilling in bone. This study also suggests the further research on establishing a relationship between surface integrity of a surgical drill bit and irreversible damage that it can induce in delicate tissues of bone using different drill sizes as well as drilling parameters and conditions.

Quantification and comparison of the regional acceleratory phenomenon in bone following piezosurgery or bur osteotomy: A pilot study in rats

BACKGROUND/OBJECTIVE

The Regional Acceleratory Phenomenon (RAP) can be induced surgically via decortication (selective cortical penetrations) of bone to accelerate orthodontic tooth movement. Few studies have compared the impact and efficiency of different decortication methods to induce the RAP. The aim of this study was to determine if there is a significant difference in the intensity of the RAP induced by a surgical defect created either using a piezoelectric knife or a rotary bur.

METHODS

Twenty-two Sprague-Dawley rats were divided into two treatment groups (each n = 8) and a control group (n = 6). The treatment groups were subjected to transcortical penetrations (TP) of the right tibia using either a piezoelectric knife (PTP) or a rotary bur (BTP). The right tibias of the control group animals had reflection of tissues (SHAM) and the left legs were kept for comparison (INTACT). The animals were killed at 7 and 14 days after the operation in an equally distributed manner. Microcomputed tomography images were obtained and analyzed utilizing artificial intelligence for bone cortical porosity (Ct.Po) locally and regionally.

RESULTS/CONCLUSION

Regionally, TP using a PTP induced significantly (p < .05, Kruskal-Wallis test) more Ct.Po than BTP or INTACT for both the 7- and 14-day time points. PTP was not found to induce significantly more Ct.Po than SHAM at any time point. However, PTP induced significantly more Ct.Po than the INTACT group for each time point, while SHAM did not. The local analysis did not reveal any relevant significant differences between groups.

An Analysis of Volume, Length and Segmentation of Free Fibula Flap in Reconstruction of the Jaws: Investigation of Their Role on Flap Failure

Reconstruction of defects of the jaws is mainly performed via free fibula flap. An incidence of 2–21% of overall flap failure is still described. We investigated the roles of volume, length and number of fibula flap segments on flap survival using novel three-dimensional segmentation tools. We also analyzed the role of other possible risk factors. Seventy-one consecutive patients with a follow up of at least three months and who underwent free fibula flap reconstruction in a single center between 2002 and 2022 have been evaluated. A total of 166 fibula segments were analyzed. Malignancies were the main reason of resection (45.1%). In 69% of the cases a reconstruction of the mandible was performed. The flaps were mainly divided in two segments (39%) (range 1–4), with a mean length of 2.52 cm and a mean volume was 3.37 cm3. Total flap failure (TFF) occurred in 12 cases, (16.9%), while partial flap failure (PFF) appeared in 3 patients (4.2%). Volume, length and number of fibula flap segments did not seem to influence flap failure incidence in uni- and multivariate analysis. Reconstruction of the maxilla and use of a recipient vessel different from the facial artery seemed to significantly impact on flap failure. Smoking and previous surgeries showed a higher trend to flap failure, but they did not reach statistical significance. Prospective and multicentric analysis on a wider population should be assessed.

Pulsed Electro-Magnetic Field (PEMF) Effect on Bone Healing in Animal Models: A Review of Its Efficacy Related to Different Type of Damage

Simple Summary

Pulsed electromagnetic fields (PEMFs) are a type of biophysical stimulation that has been shown to be effective in improving bone regeneration and preventing bone loss. Their use dates back to the 1970s, but a gold standard treatment protocol has not yet been defined. PEMF efficacy relies on the generation of biopotentials, which activate several molecular pathways. There is currently no clear understanding of the effects on bone healing and, in addition, there are several animal models relevant to this issue. Therefore, drawing guidelines and conclusions from the analysis of the studies is difficult. In vivo investigations on PEMF stimulation are reviewed in this paper, focusing on molecular and morphological improvements in bone. Currently, there is little knowledge about the biological mechanism of PEMF and its effect on bone healing. This is due to the variability of crucial characteristics of electro-magnetic fields, such as amplitude and exposure frequency, which may influence the type of biological response. Furthermore, a different responsiveness of cells involved in the bone healing process is documented. Heterogeneous setting parameters and different outcome measures are considered in various animal models. Therefore, achieving comparable results is difficult.

Abstract

Biophysical energies are a versatile tool to stimulate tissues by generating biopotentials. In particular, pulsed electromagnetic field (PEMF) stimulation has intrigued researchers since the 1970s. To date, many investigations have been carried out in vivo, but a gold standard treatment protocol has not yet been defined. The main obstacles are represented by the complex setting of PEMF characteristics, the variety of animal models (including direct and indirect bone damage) and the lack of a complete understanding of the molecular pathways involved. In the present review the main studies about PEMF stimulation in animal models with bone impairment were reviewed. PEMF signal characteristics were investigated, as well as their effect on molecular pathways and osseous morphological features. We believe that this review might be a useful starting point for a prospective study in a clinical setting. Consistent evidence from the literature suggests a potential beneficial role of PEMF in clinical practice. Nevertheless, the wide variability of selected parameters (frequency, duration, and amplitude) and the heterogeneity of applied protocols make it difficult to draw certain conclusions about PEMF effectiveness in clinical implementation to promote bone healing. Deepening the knowledge regarding the most consistent results reported in literature to date, we believe that this review may be a useful starting point to propose standardized experimental guidelines. This might provide a solid base for further controlled trials, to investigate PEMF efficacy in bone damage conditions during routine clinical practice.

Piezosurgery versus Conventional Cutting Techniques in Craniofacial Surgery: A Systematic Review and Meta-Analysis

BACKGROUND

Despite its increasing use in craniofacial surgery, the evidence for piezosurgery over conventional bone-cutting techniques has not been critically appraised. The purpose of this systematic review and meta-analysis was to identify and assess the evidence that exists for the use of piezosurgery in craniofacial surgery.

METHODS

A systematic review was undertaken using a computerized search. Publication descriptors, methodologic details, and outcomes were extracted. Articles were assessed using the methodologic index for nonrandomized studies and Cochrane instruments. Random effects meta-analysis was completed.

RESULTS

Thirty-nine studies were included. Most studies were published within the past 5 years (51.3 percent) and were randomized controlled trials (56.4 percent). The mean age of patients was 27 years (range, 0.2 to 57 years), and the mean sample size was 44 (range, 12 to 180). Meta-analysis revealed that compared to conventional instruments, piezosurgery had a lower postoperative incidence of sensory disturbance, principally in mandibular procedures (OR, 0.29; 95 percent CI, 0.11 to 0.77; p = 0.01) and pain at postoperative day 3 (mean difference, -0.86; 95 percent CI, -1.20 to -0.53; p < 0.01). There was no statistically significant difference in operating room time (mean difference, 8.60; 95 percent CI, -1.27 to 18.47; p = 0.80) or osteotomy time (mean difference, 0.35; 95 percent CI, -2.99 to 3.68; p = 0.84). Most studies were clinically homogenous (92 percent) and of high quality based on the methodologic index for nonrandomized studies instrument (84 percent). Few studies had domains at high risk of bias based on the Cochrane instrument (28.6 percent).

CONCLUSIONS

Piezosurgery has considerable benefits when compared to conventional instruments. Future studies should investigate its cost-effectiveness and benefits in terms of blood loss, edema/ecchymosis, and patient satisfaction.

A Case Report of a Solitary Fibrous Tumor of the Maxillary Sinus

A solitary fibrous tumor (SFT) is a benign neoplasm, firstly described as a mesenchymal tumor of the pleura. Its incidence range in the head and neck region is about 5–27%, but only rarely does it affect paranasal sinuses. The differential diagnosis is challenging, owing to its erosive growth pattern and immuno-histochemical features. SFTs have an aggressive behavior and an important recurrence potential. Therefore, a radical surgical excision is the gold standard therapeutic procedure. A rare SFT originating from the right maxillary sinus is reported here. The 37-year-old patient presented to the outpatient clinic with a painful expansive lesion in the whole right maxillary region. The overlying skin was inflamed and the patient had no epistaxis episodes. The 1.5 dentary element tested negative for vitality; however, a puncture of the lesion led to a hematic spill and no purulent discharge. An endoscopic-guided biopsy was suggestive either of SFT or hemangioperictoma, excluding a malignant neoplasm. A multi-equipe surgical team was activated. The lesion was embolized in order to achieve a good hemostatic control and, after 48 h, the neoplasm was radically excised with a combined open and endoscopic approach. The patient was disease-free at 12-month radiological and clinical follow-up. Given the rarity of this lesion and the delicacy required in addressing head and neck neoplasms, we believe that the present case report might be of help in further understanding how to approach cranio-facial SFTs.

Histological evaluation of thermal damage to Osteocytes: A comparative study of conventional and ultrasonic-assisted bone grinding

This paper addresses an important issue faced by neurosurgeons during surgical skull bone grinding, a common process used to remove bone in skull base tumour removal surgery to enable the neurosurgeon to reach the target region. The heat generated during bone grinding could harm the soft tissues and can lead to osteonecrosis and cell death. In the present study, a novel process of rotary ultrasonic bone grinding (RUBG) was proposed for osteotomy to limit the temperature to a safe level. A systematic investigation was conducted to determine the effect of varying process parameters on osteonecrosis at the cut surface. Three input parameters - rotational speed, feed rate and frequency - were investigated (at three levels) in terms of change in temperature and thermal biological damage. A sterile solution was used as a coolant to irrigate the grinding zone. Viable lacunae (filled osteocytes), non-viable lacunae (empty lacunae), necrosed tissues, and Haversian canal were found during the histological examination. Statistical analysis revealed that feed rate (45.43%) had the highest contribution towards temperature rise during grinding, followed by ultrasonic frequency (23.87%), and rotational speed (12.85%). The optimal machining parameters to avoid osteonecrosis and thermal trauma were rotational speed 35,000 rpm, feed rate 20 mm/min and ultrasonic frequency 20 kHz. Furthermore, histograms revealed that ultrasonic skull bone grinding was associated with greater cell viability and reduced temperature compared with conventional bone grinding.

Extended and unusual indications in jaw reconstruction with the fibula flap: An overview based on our 30-year experience

Since the introduction of fibula flap as a reconstructive technique, an evolution of indications has been observed. Our first report of a traumatic mandibular reconstruction using fibula flap was in 1992. The vast majority of indications for surgery, are: malignant tumors, benign neoplasms, osteoradionecrosis and traumas. Nevertheless, extended indications have been described such as the treatment of dentoalveolar defect without bone discontinuity or reconstruction of maxilla defect up to type III (A and B), according to Cordeiro's classification. Unusual indications include cleft palate malformations with bone discontinuity less than 6 cm. Moreover, a particular attention should be focus on fibula flap harvest with more innovative technologies than traditional use of monopolar or bipolar and their advantages in pre and postoperative management.

Multimodal Evaluation of the Spatiotemporal Variations of Periprosthetic Bone Properties

Titanium implants are widely used in dental and orthopedic surgeries. However, implant failures still occur because of a lack of implant stability. The biomechanical properties of bone tissue located around the implant need to be assessed to better understand the osseointegration phenomena and anticipate implant failure. The aim of this study was to explore the spatiotemporal variation of the microscopic elastic properties of newly formed bone tissue close to an implant. Eight coin-shaped Ti6Al4V implants were inserted into rabbit tibiae for 7 and 13 weeks using an in vivo model allowing the distinction between mature and newly formed bone in a standardized configuration. Nanoindentation and micro-Brillouin scattering measurements were carried out in similar locations to measure the indentation modulus and the wave velocity, from which relative variations of bone mass density were extracted. The indentation modulus, the wave velocity and mass density were found to be higher (1) in newly formed bone tissue located close to the implant surface, compared to mature cortical bone tissue, and (2) after longer healing time, consistently with an increased mineralization. Within the bone chamber, the spatial distribution of elastic properties was more heterogeneous for shorter healing durations. After 7 weeks of healing, bone tissue in the bone chamber close to the implant surface was 12.3% denser than bone tissue further away. Bone tissue close to the chamber edge was 16.8% denser than in its center. These results suggest a bone spreading pathway along tissue maturation, which is confirmed by histology and consistent with contact osteogenesis phenomena.

Spatio-temporal evolution of hydroxyapatite crystal thickness at the bone-implant interface

A better understanding of bone nanostructure around the bone-implant interface is essential to improve longevity of clinical implants and decrease failure risks. This study investigates the spatio-temporal evolution of mineral crystal thickness and plate orientation in newly formed bone around the surface of a metallic implant. Standardized coin-shaped titanium implants designed with a bone chamber were inserted into rabbit tibiae for 7 and 13 weeks. Scanning measurements with micro-focused small-angle X-ray scattering (SAXS) were carried out on newly formed bone close to the implant and in control mature cortical bone. Mineral crystals were thinner close to the implant (1.8 ± 0.45 nm at 7 weeks and 2.4 ± 0.57 nm at 13 weeks) than in the control mature bone tissue (2.5 ± 0.21 nm at 7 weeks and 2.8 ± 0.35 nm at 13 weeks), with increasing thickness over healing time (+30 % in 6 weeks). These results are explained by younger bone close to the implant, which matures during osseointegration. Thinner mineral crystals parallel to the implant surface within the first 100 µm indicate that the implant affects the ultrastructure of neighbouring bone , potentially due to heterogeneous interfacial stresses, and suggest a longer maturation process of bone tissue and difficulty in binding to the metal. The bone growth kinetics within the bone chamber was derived from the spatio-temporal evolution of bone tissue's nanostructure, coupled with microtomographic imaging. The findings indicate that understanding mineral crystal thickness or plate orientation can improve our knowledge of osseointegration.

Bone Healing Evaluation Following Different Osteotomic Techniques in Animal Models: A Suitable Method for Clinical Insights

Osteotomy is a common step in oncological, reconstructive, and trauma surgery. Drilling and elevated temperature during osteotomy produce thermal osteonecrosis. Heat and associated mechanical damage during osteotomy can impair bone healing, with consequent failure of fracture fixation or dental implants. Several ex vivo studies on animal bone were recently focused on heating production during osteotomy with conventional drill and piezoelectric devices, particularly in endosseous dental implant sites. The current literature on bone drilling and osteotomic surface analysis is here reviewed and the dynamics of bone healing after osteotomy with traditional and piezoelectric devices are discussed. Moreover, the methodologies involved in the experimental osteotomy and clinical studies are compared, focusing on ex vivo and in vivo findings.

Dynamics of implant site preparation affecting the quality of osseointegrated implants in the maxillary aesthetic zone

PURPOSE

This study compared piezoelectric (PE) and conventional drills (CD) for maxillary aesthetic zone implant insertion.

MATERIAL AND METHODS

This was a prospective split-mouth study. Implants were divided into two groups. Beds were prepared with CDs in group I and PE in group II. The implant stability quotient (ISQ) of the mechanical implant stability (MIS) was measured intraoperatively. The ISQ of the biological implant stability (BIS) was recorded at postoperative second and fourth months. Marginal bone loss (MBL) and bone density (BMD) were measured in the first and second years after prosthetic loading. The osteotomy time was also documented for both techniques. P values <0.05 were considered significant.

RESULTS

Sixty implants in 30 patients were included. PE provided a significantly higher ISQ. All values were above 70 throughout the follow-up period. The mean of the ISQ for MIS was 63.78 ± 1.03 and 73.89 ± 1.05 in group I and group II, respectively (p = 0.003). PE needed significantly longer osteotomy time with a mean of 11.99 ± 0.839 min. The BIS quality had high stability in group II and medium stability in group I throughout the study period. Its values decreased in both groups. Group II had a lesser percentage of decrease. However, it was significant only at time intervals between intraoperative and two months' postoperative (p = 0.004). MBL and BMD demonstrated insignificant results.

CONCLUSION

The implant site preparation with PE devices should be preferred to CDs whenever possible, because they seem to enhance implant stability and osseointegration, especially at the initial stages of healing.

Cell Proliferation to Evaluate Preliminarily the Presence of Enduring Self-Regenerative Antioxidant Activity in Cerium Doped Bioactive Glasses

(1) Background: a cell evaluation focused to verify the self-regenerative antioxidant activity is performed on cerium doped bioactive glasses. (2) Methods: the glasses based on 45S5 Bioglass^®, are doped with 1.2 mol%, 3.6 mol% and 5.3 mol% of CeO₂ and possess a polyhedral shape (~500 µm²). Glasses with this composition inhibit oxidative stress by mimicking catalase enzyme (CAT) and superoxide dismutase (SOD) activities; moreover, our previous cytocompatibility tests (neutral red (NR), 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Bromo-2-deoxyUridine (BrdU)) reveal that the presence of cerium promotes the absorption and vitality of the cells. The same cytocompatibility tests were performed and repeated, in two different periods (named first and second use), separated from each other by four months. (3) Results: in the first and second use, NR tests indicate that the presence of cerium promotes once again cell uptake and viability, especially after 72 h. A decrease in cell proliferation it is observed after MTT and BrdU tests only in the second use. These findings are supported by statistically significant results (4) Conclusions: these glasses show enhanced proliferation, both in the short and in the long term, and for the first time such large dimensions are studied for this kind of study. A future prospective is the implantation of these bioactive glasses as bone substitute in animal models.

Primary Intraosseous Squamous Cell Carcinoma of the Anterior Mandible Arising in an Odontogenic Cyst in 34-Year-Old Male

Primary intraosseous squamous cell carcinoma (PIOSCC) is a rare and aggressive malignancy arising exclusively within the jaws, without any initial connection with the oral mucosa. The etiology and the epidemiology are unclear due to the rarity of the disease, and there is no current universally accepted staging or treatment protocol. Clinically, the posterior mandible is the most affected site, and common symptoms are swelling and pain. The diagnosis is often difficult either because it requires stringent criteria to be satisfied or because of the absence of a pathognomonic histological pattern. Aggressive surgery is the first-choice treatment, often followed by radiotherapy. The lymph nodal status seems to be the most important factor influencing the prognosis, which is usually poor, with a 5-year survival rate ranging from 30% to 40%. In the present article, we report an unusual case of cystogenic PIOSCC interesting the anterior mandible of a young 34-year-old male, which came to our attention after complaint about recurrent infective episodes affecting a dentigerous cyst (impacted lower canine) discovered ten years before. The age, site, and extension are uncommon. Extensive surgical treatment with fibula free flap reconstruction, adjuvant therapy, and salvage surgery was carried out. The patient was disease-free at a 31-month follow-up.

Clinical Management of Acinic Cell Carcinoma of the Lacrimal Gland

To report a case of acinic cell carcinoma occurred in the lacrimal gland. A 59-year-old man was admitted because of sudden blurring of vision, progressive proptosis of the left eye, and mild double vision in left and down directions of the gaze (Hess-Lancaster test). His medical history detailed controlled bilateral keratoconus and open angle glaucoma. On examination, the best corrected visual acuity decreased from 8/20 till 1/50 in one week. There was a swelling of the left upper eyelid. A hard and tender mass was palpated in the superior temporal left orbit. Ultrasound scan showed an extraconal solid mass, situated in the superior lateral corner of the orbit. Computed tomography and magnetic resonance imaging (MRI) revealed a mass of two centimeters in diameter, with round well-defined outline, within the lacrimal gland. We performed an enucleoresection of the mass, via a coronal approach and a lateral orbitotomy by a piezosurgical device. The lesion appeared nodular, brownish, measuring about 2 × 1.5 cm. Histopathological findings were consistent with acinic cell carcinoma with a microcystic, focally papillary-cystic growth of pattern. Follow-up MRI outcomes led to removal of the residual lacrimal gland for suspicion of recurrence. No tumor recurrences where detected at 7-year follow-up.

From Osteoclast Differentiation to Osteonecrosis of the Jaw: Molecular and Clinical Insights

Bone physiology relies on the delicate balance between resorption and formation of its tissue. Bone resorption depends on a process called osteoclastogenesis in which bone-resorbing cells, i.e., osteoclasts, are produced by the differentiation of more undifferentiated progenitors and precursors. This process is governed by two main factors, monocyte-colony stimulating factor (M-CSF) and receptor activator of NFκB ligand (RANKL). While the former exerts a proliferating effect on progenitors/precursors, the latter triggers a differentiation effect on more mature cells of the same lineage. Bone homeostasis requires a perfect space–time coordination of the involved signals. When osteoclastogenesis is poorly balanced with the differentiation of the bone forming counterparts, i.e., osteoblasts, physiological bone remodelling can turn into a pathological state, causing the systematic disruption of bone tissue which results in osteopenia or osteolysis. Examples of these conditions are represented by osteoporosis, Paget’s disease, bone metastasis, and multiple myeloma. Therefore, drugs targeting osteoclastogenesis, such as bisphosphonates and an anti-RANKL monoclonal antibody, have been developed and are currently used in the treatment of such diseases. Despite their demonstrated therapeutic efficacy, these agents are unfortunately not devoid of side effects. In this regard, a condition called osteonecrosis of the jaw (ONJ) has been recently correlated with anti-resorptive therapy. In this review we will address the involvement of osteoclasts and osteoclast-related factors in the pathogenesis of ONJ. It is to be hoped that a better understanding of the biological mechanisms underlying bone remodelling will help in the design a medical therapeutic approach for ONJ as an alternative to surgical procedures.

In-vitro experimental study of histopathology of bone in vibrational drilling

Drilling is a common surgical procedure for fracture treatment and reconstruction in multiple surgical fields, including orthopaedics, neurology, and dentistry. Drilling delicate tissue (such as bone) with a hard metallic tool is considered notorious for inducing mechanical and thermal damage, which can adversely affect osseointegration and may weaken the bond between the bone and implant, or other fixative devices anchoring the bone. The aim of this study is to explore the benefits of vibrational drilling (VD) in overcoming the complications associated with conventional drilling (CD). Drilling tests were performed on fresh cortical bone with the intention of investigating the effect of a range of frequencies, in combination with drilling speed and feed rate, on biological damage around the drilling region using histological sections of skeletally mature bone. The study examined the most influential factors and optimal combination of parameters for safe and efficient drilling in bone. Results from Taguchi grey relational analysis showed that a lower drilling speed and feed rate combined with a frequency of 20 kHz were favourable parameters for safe drilling in bone. Accordingly, VD using controlled parameters may be an alternative to CD in bone surgical procedures.