Dror Allon - Academia.edu (original) (raw)
Papers by Dror Allon
International Journal of Oral and Maxillofacial Surgery, Mar 1, 2017
Journal of Craniofacial Surgery, Mar 13, 2023
Objective: The aim of this study was to simulate reusing an opened package of bone substitute (BS... more Objective: The aim of this study was to simulate reusing an opened package of bone substitute (BS) under typical clinical conditions, by analyzing bacterial growth in samples of resealed packages of alloplast and xenograft BS following different time periods up to a week. Materials and Methods: The experiment was performed in 2 stages: dry stage and wet stage. In the dry stage, BS samples were exposed to air for 15 minutes and then were sealed again in their original package. After several “aging” periods [no aging (t0), 24 hours (t1), and 1 week (t7)], BS samples were plated onto brain heart infusion agar and were incubated at 37 °C for 24 hours under aerobic conditions. Bacterial colonies were enumerated and colony forming units per 1 mL was calculated. In the wet stage, the experiment was repeated but BSs were left to age in a brain heart infusion broth to simulate a more supporting humid environment to encourage bacterial growth. Results: In the dry stage of the experiment, no bacterial growth was detected in both xenograft and alloplast samples (colony forming units/mL=0), in any of the time points (t0, t1, t7). In the wet stage, average bacterial growth was 0 for both groups in t0. In t1: 1.14 × 104±4.16 × 103 for the xenograft and 7.73 × 105± 9.99 × 105 for the alloplast. In t7: 1.64 × 109±1.82 × 108 in the xenograft compared with 8.86 × 108±4.00 × 108 for the alloplast. Analysis of variance with repeated measures showed a significant difference in comparison of the 2 BSs for each time group (t1 and t7) (P<0.005). Conclusion: Under dry conditions, in a resealed package, there was no bacterial growth for up to 1 week for both BSs. Once the BSs are introduced to a humid environment, which supports bacterial growth, the xenograft BS allowed more rapid bacterial growth, compared with the alloplastic BS.
Journal of Oral and Maxillofacial Surgery, 2007
Oral Surgery, Oral Medicine, Oral Pathology, and Oral Radiology, Dec 1, 2014
Oral Surgery, Oral Medicine, Oral Pathology, and Oral Radiology, Mar 1, 2015
OBJECTIVES: To investigate the expression of anti-and proapoptosis markers, metallothionein (MT),... more OBJECTIVES: To investigate the expression of anti-and proapoptosis markers, metallothionein (MT), and caspase-2, in the epithelial and inflammatory cells of oral lichen planus (OLP) patients, and to investigate the association with clinical parameters. MATERIALS AND METHODS: Included were biopsies of 70 OLP patients. The clinical data were collected from patients' charts. The expression of MT and caspase-2 was immunomorphometrically analyzed in the epithelial and inflammatory cells, and the results were correlated with the clinical presentation. RESULTS: The epithelial and inflammatory cells expressed MT (10.2 AE 5.75 and 0.68 AE 0.86) and caspase-2 (1.54 AE 2.6 and 0.98 AE 1.15) which show a trend toward an inverse expression. The expression of MT in the epithelium was significantly higher in patients presenting with keratotic lichen planus than in patients with the atrophic and erosive forms (P = 0.0008). In the inflammatory cells, the expression of MT was inversely correlated with increasing age (R = 0.34, P = 0.0069). CONCLUSIONS: The pattern of expression of MT and caspase-2 in OLP suggests an extensive antiapoptotic response in the keratotic form of the disease. Symptomatic patients may benefit from therapy targeted to apoptosis in the future.
Oral Diseases, Jul 10, 2013
ObjectivesNecrotizing sialometaplasia (NS) is an uncommon reactive lesion involving the minor sal... more ObjectivesNecrotizing sialometaplasia (NS) is an uncommon reactive lesion involving the minor salivary glands. This study aimed to investigate the expression of hypoxia‐inducible factor alpha (HIF‐1α), vascular endothelial growth factor (VEGF), and epithelial growth factor receptor (EGFR) in the pathogenesis of NS.MethodsParaffin‐embedded tissue sections from 10 cases of NS were immunohistochemically stained for HIF‐1α, VEGF, and EGFR. A semiquantitative morphometric analysis was performed and compared with normal palatal salivary glands and traumatic ulcerations.ResultsHypoxia‐inducible factor alpha staining was observed in most elements of the affected area, the acini and ducts of the involved salivary glands as well as in the inflammatory infiltrate, the endothelial cells, and stromal cells. HIF‐1α was almost absent in the control glands (P < 0.0001). VEGF staining was positive in the stromal capillaries and in the inflammatory infiltrate. The expression was higher in cases of NS compared with the normal salivary glands (P < 0.001). EGFR was expressed in the surface epithelium, the pseudo‐epitheliomatous hyperplasia, and the islands of squamous metaplasia. VEGF expression in traumatic ulcerations was lower than that in cases of NS.ConclusionThis study provides molecular evidence to the role of hypoxia in NS; HIF‐1α, the main regulator of hypoxia, was expressed in the infarcted salivary glands, EGFR in the metaplastic epithelium and VEGF in the stromal capillaries, all three components are the key factors induced by hypoxia.
Applied Sciences
Background: Combined orthodontic-surgical treatment includes a thorough diagnosis and analysis of... more Background: Combined orthodontic-surgical treatment includes a thorough diagnosis and analysis of dental and facial deformities. Cephalometric analysis is a common tool for this, in which measurements of specific anatomical landmarks are performed. In order to achieve a successful surgery, orthodontic teeth preparation is mandatory, including dental decompensation before surgery. This should be planned and adequately executed to allow the surgeon to move the jaws to the correct ideal position. Aim: The current study aimed to check if the orthodontic decompensation amount is influenced and compromised by the maxillomandibular difference and if there is a correlation between the deformity’s severity and the orthodontist’s difficulty in achieving an accurate result in the orthodontic decompensation preparation. Methods: The study consisted of 50 pre-operational cephalometric radiographs of patients with Class-III (prognathic) deformity. The measurements included the angles of the upper...
Refu'at ha-peh veha-shinayim, 2016
Edentulous patients with advanced resorption of the mandible (atrophic mandible) suffer major dis... more Edentulous patients with advanced resorption of the mandible (atrophic mandible) suffer major discomfort when using dentures. Furthermore, placing dental implants is impossible due to lack of sufficient bone volume. In the past, several methods of bone grafting to the anterior mandible have been proposed. Most of them were unpredictable in either the short or long-term. In 2002 a technique for bone grafting of the anterior mandible via a submental approach was published. A wide reflection of the soft tissue was followed by implant placement. Autogenous particulate posterior iliac crest bone graft was used. The presence of the implants did not allow for contraction of the soft tissue and bone resorption. The addition of bone volume to the chin improved the facial aesthetics of the patients due to a fuller appearance of the chin and tightening of the skin of the neck. The submental approach changes the spatial orientation of the surgeon and placement of implants in the correct locatio...
Applied Sciences
One of the most challenging procedures during maxillary osteotomy is pterygomaxillary suture (PMS... more One of the most challenging procedures during maxillary osteotomy is pterygomaxillary suture (PMS) separation, due to the difficulty of directly inspecting this suture and the anatomical complexity of the adjacent structures. Knowing the precise anatomical dimensions and the position of the PMS, namely, the angle at which to approach this structure, may help in determining the proper osteotome. It will also help the oral and maxillofacial surgeon to perform this sensitive procedure more precisely and to minimize surgical complications (e.g., internal maxillary artery injury and unfavorable fracture during separation). The current study aimed to evaluate the morphology of PMS in an adult Israeli population using CBCT scans of the maxilla. Fifty CBCTs of healthy males (n = 27) and females (n = 23) were collected and analyzed. The vertical height, maximal thickness, and angulation of the PMS relative to the midsagittal plane of the skull were evaluated on both the right and left sides ...
Applied Sciences
Before orthognathic surgery, a thorough diagnosis of the maxillofacial structure is performed for... more Before orthognathic surgery, a thorough diagnosis of the maxillofacial structure is performed for combined orthodontic–surgical treatment planning. One of the tools that are used for this collaboration is the cephalometric radiograph. Cephalometric analysis is a method for measuring the location of specific anatomical landmarks upon a cephalogram. Some of these parameters are more difficult to define accurately in cases of dentofacial deformities. Therefore, the data obtained from different examiners are characterized by high variability. The present study aimed to examine whether there is a significant variation in the physicians’ measurements between orthognathic Class I (normal) cases and the cases of skeletal deformity Class III. The study involved ten physicians with a mean age of 27. All physicians underwent appropriate instruction for reading and analyzing cephalometric radiographs, and all physicians were instructed about their role in the study. Each participant received 10...
Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology, 2015
Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons, 2015
Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology, 2013
cohorts. Trial results have shown (1) that there were no deleterious effects; (2) that BRB gel de... more cohorts. Trial results have shown (1) that there were no deleterious effects; (2) that BRB gel decreased OIN clinical size (BRB, P ¼ .0019) whereas 17 of 18 placebo gel lesions increased in size (P ¼ .0395; 2-tailed Mann-Whitney U test); (3) that BRB gel reduced OIN histologic grade (BRB, P ¼ .0488; placebo, P ¼ .4961; Wilcoxon matched-pairs signed-rank test); (4) that BRB gel reduced LOH indices at 9p markers (BRB, P ¼ .0156; placebo, P ¼ .9999; Wilcoxon matched-pairs signed-rank test); and (5) that there were comparable 3-month recurrences. Analyses of COX-2, iNOS, and MVD; metabolic profiles (Western blots); LOH analyses at p53 and fragile histidine triad (FHIT) loci; and p16 promoter methylation studies are ongoing. Our results confirm that BRB constituentsdand not gel base componentsdprovide the chemopreventive activity and demonstrate clinically relevant efficacy. As many key BRB active constituents are redox-active molecules, we speculate that dysplastic phenotype reduction reflects redox-mediated modulation of gene expression and induction of apoptosis. The comparable recurrence rates imply persistence of altered stem cells and suggest a need for sustained treatment.
Clinical Pediatrics, 2007
The aim of the study was to determine if doxycycline causes tooth staining in young children. A d... more The aim of the study was to determine if doxycycline causes tooth staining in young children. A dentist examined 31 randomized children who had been treated with doxycycline and 30 children who had not received doxycycline. Mean age of the children was 10.4 ∓ 2.1 years. Mean age at receipt of the first doxycycline treatment was 4.1 ∓ 1.6 years, and mean number of doxycycline courses was 2.0 ∓ 1.3. No tooth staining was detected by the dentist in any of the children in either group. These findings indicate that treatment with doxycycline in children aged 2 to 8 years is not associated with tooth staining.
Breast Diseases: A Year Book Quarterly, 2009
Electronic-photonic integrated circuits (EPICs) are a promising technology for overcoming bandwid... more Electronic-photonic integrated circuits (EPICs) are a promising technology for overcoming bandwidth and power-consumption bottlenecks of traditional integrated circuits. Silicon is a good candidate for building such devices, due to its high-index contrast and low propagation loss at telecom wavelengths. The current thesis presents recent advances in demonstrating discrete components built in silicon-on-insulator (SOI) platforms, around 1550 nm, that can be used as CONTENTS LIST OF FIGURES .
British Journal of Oral and Maxillofacial Surgery, 1990
ABSTRACT
Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology, 2016
Journal of Craniofacial Surgery
International Journal of Oral and Maxillofacial Surgery, Mar 1, 2017
Journal of Craniofacial Surgery, Mar 13, 2023
Objective: The aim of this study was to simulate reusing an opened package of bone substitute (BS... more Objective: The aim of this study was to simulate reusing an opened package of bone substitute (BS) under typical clinical conditions, by analyzing bacterial growth in samples of resealed packages of alloplast and xenograft BS following different time periods up to a week. Materials and Methods: The experiment was performed in 2 stages: dry stage and wet stage. In the dry stage, BS samples were exposed to air for 15 minutes and then were sealed again in their original package. After several “aging” periods [no aging (t0), 24 hours (t1), and 1 week (t7)], BS samples were plated onto brain heart infusion agar and were incubated at 37 °C for 24 hours under aerobic conditions. Bacterial colonies were enumerated and colony forming units per 1 mL was calculated. In the wet stage, the experiment was repeated but BSs were left to age in a brain heart infusion broth to simulate a more supporting humid environment to encourage bacterial growth. Results: In the dry stage of the experiment, no bacterial growth was detected in both xenograft and alloplast samples (colony forming units/mL=0), in any of the time points (t0, t1, t7). In the wet stage, average bacterial growth was 0 for both groups in t0. In t1: 1.14 × 104±4.16 × 103 for the xenograft and 7.73 × 105± 9.99 × 105 for the alloplast. In t7: 1.64 × 109±1.82 × 108 in the xenograft compared with 8.86 × 108±4.00 × 108 for the alloplast. Analysis of variance with repeated measures showed a significant difference in comparison of the 2 BSs for each time group (t1 and t7) (P<0.005). Conclusion: Under dry conditions, in a resealed package, there was no bacterial growth for up to 1 week for both BSs. Once the BSs are introduced to a humid environment, which supports bacterial growth, the xenograft BS allowed more rapid bacterial growth, compared with the alloplastic BS.
Journal of Oral and Maxillofacial Surgery, 2007
Oral Surgery, Oral Medicine, Oral Pathology, and Oral Radiology, Dec 1, 2014
Oral Surgery, Oral Medicine, Oral Pathology, and Oral Radiology, Mar 1, 2015
OBJECTIVES: To investigate the expression of anti-and proapoptosis markers, metallothionein (MT),... more OBJECTIVES: To investigate the expression of anti-and proapoptosis markers, metallothionein (MT), and caspase-2, in the epithelial and inflammatory cells of oral lichen planus (OLP) patients, and to investigate the association with clinical parameters. MATERIALS AND METHODS: Included were biopsies of 70 OLP patients. The clinical data were collected from patients' charts. The expression of MT and caspase-2 was immunomorphometrically analyzed in the epithelial and inflammatory cells, and the results were correlated with the clinical presentation. RESULTS: The epithelial and inflammatory cells expressed MT (10.2 AE 5.75 and 0.68 AE 0.86) and caspase-2 (1.54 AE 2.6 and 0.98 AE 1.15) which show a trend toward an inverse expression. The expression of MT in the epithelium was significantly higher in patients presenting with keratotic lichen planus than in patients with the atrophic and erosive forms (P = 0.0008). In the inflammatory cells, the expression of MT was inversely correlated with increasing age (R = 0.34, P = 0.0069). CONCLUSIONS: The pattern of expression of MT and caspase-2 in OLP suggests an extensive antiapoptotic response in the keratotic form of the disease. Symptomatic patients may benefit from therapy targeted to apoptosis in the future.
Oral Diseases, Jul 10, 2013
ObjectivesNecrotizing sialometaplasia (NS) is an uncommon reactive lesion involving the minor sal... more ObjectivesNecrotizing sialometaplasia (NS) is an uncommon reactive lesion involving the minor salivary glands. This study aimed to investigate the expression of hypoxia‐inducible factor alpha (HIF‐1α), vascular endothelial growth factor (VEGF), and epithelial growth factor receptor (EGFR) in the pathogenesis of NS.MethodsParaffin‐embedded tissue sections from 10 cases of NS were immunohistochemically stained for HIF‐1α, VEGF, and EGFR. A semiquantitative morphometric analysis was performed and compared with normal palatal salivary glands and traumatic ulcerations.ResultsHypoxia‐inducible factor alpha staining was observed in most elements of the affected area, the acini and ducts of the involved salivary glands as well as in the inflammatory infiltrate, the endothelial cells, and stromal cells. HIF‐1α was almost absent in the control glands (P < 0.0001). VEGF staining was positive in the stromal capillaries and in the inflammatory infiltrate. The expression was higher in cases of NS compared with the normal salivary glands (P < 0.001). EGFR was expressed in the surface epithelium, the pseudo‐epitheliomatous hyperplasia, and the islands of squamous metaplasia. VEGF expression in traumatic ulcerations was lower than that in cases of NS.ConclusionThis study provides molecular evidence to the role of hypoxia in NS; HIF‐1α, the main regulator of hypoxia, was expressed in the infarcted salivary glands, EGFR in the metaplastic epithelium and VEGF in the stromal capillaries, all three components are the key factors induced by hypoxia.
Applied Sciences
Background: Combined orthodontic-surgical treatment includes a thorough diagnosis and analysis of... more Background: Combined orthodontic-surgical treatment includes a thorough diagnosis and analysis of dental and facial deformities. Cephalometric analysis is a common tool for this, in which measurements of specific anatomical landmarks are performed. In order to achieve a successful surgery, orthodontic teeth preparation is mandatory, including dental decompensation before surgery. This should be planned and adequately executed to allow the surgeon to move the jaws to the correct ideal position. Aim: The current study aimed to check if the orthodontic decompensation amount is influenced and compromised by the maxillomandibular difference and if there is a correlation between the deformity’s severity and the orthodontist’s difficulty in achieving an accurate result in the orthodontic decompensation preparation. Methods: The study consisted of 50 pre-operational cephalometric radiographs of patients with Class-III (prognathic) deformity. The measurements included the angles of the upper...
Refu'at ha-peh veha-shinayim, 2016
Edentulous patients with advanced resorption of the mandible (atrophic mandible) suffer major dis... more Edentulous patients with advanced resorption of the mandible (atrophic mandible) suffer major discomfort when using dentures. Furthermore, placing dental implants is impossible due to lack of sufficient bone volume. In the past, several methods of bone grafting to the anterior mandible have been proposed. Most of them were unpredictable in either the short or long-term. In 2002 a technique for bone grafting of the anterior mandible via a submental approach was published. A wide reflection of the soft tissue was followed by implant placement. Autogenous particulate posterior iliac crest bone graft was used. The presence of the implants did not allow for contraction of the soft tissue and bone resorption. The addition of bone volume to the chin improved the facial aesthetics of the patients due to a fuller appearance of the chin and tightening of the skin of the neck. The submental approach changes the spatial orientation of the surgeon and placement of implants in the correct locatio...
Applied Sciences
One of the most challenging procedures during maxillary osteotomy is pterygomaxillary suture (PMS... more One of the most challenging procedures during maxillary osteotomy is pterygomaxillary suture (PMS) separation, due to the difficulty of directly inspecting this suture and the anatomical complexity of the adjacent structures. Knowing the precise anatomical dimensions and the position of the PMS, namely, the angle at which to approach this structure, may help in determining the proper osteotome. It will also help the oral and maxillofacial surgeon to perform this sensitive procedure more precisely and to minimize surgical complications (e.g., internal maxillary artery injury and unfavorable fracture during separation). The current study aimed to evaluate the morphology of PMS in an adult Israeli population using CBCT scans of the maxilla. Fifty CBCTs of healthy males (n = 27) and females (n = 23) were collected and analyzed. The vertical height, maximal thickness, and angulation of the PMS relative to the midsagittal plane of the skull were evaluated on both the right and left sides ...
Applied Sciences
Before orthognathic surgery, a thorough diagnosis of the maxillofacial structure is performed for... more Before orthognathic surgery, a thorough diagnosis of the maxillofacial structure is performed for combined orthodontic–surgical treatment planning. One of the tools that are used for this collaboration is the cephalometric radiograph. Cephalometric analysis is a method for measuring the location of specific anatomical landmarks upon a cephalogram. Some of these parameters are more difficult to define accurately in cases of dentofacial deformities. Therefore, the data obtained from different examiners are characterized by high variability. The present study aimed to examine whether there is a significant variation in the physicians’ measurements between orthognathic Class I (normal) cases and the cases of skeletal deformity Class III. The study involved ten physicians with a mean age of 27. All physicians underwent appropriate instruction for reading and analyzing cephalometric radiographs, and all physicians were instructed about their role in the study. Each participant received 10...
Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology, 2015
Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons, 2015
Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology, 2013
cohorts. Trial results have shown (1) that there were no deleterious effects; (2) that BRB gel de... more cohorts. Trial results have shown (1) that there were no deleterious effects; (2) that BRB gel decreased OIN clinical size (BRB, P ¼ .0019) whereas 17 of 18 placebo gel lesions increased in size (P ¼ .0395; 2-tailed Mann-Whitney U test); (3) that BRB gel reduced OIN histologic grade (BRB, P ¼ .0488; placebo, P ¼ .4961; Wilcoxon matched-pairs signed-rank test); (4) that BRB gel reduced LOH indices at 9p markers (BRB, P ¼ .0156; placebo, P ¼ .9999; Wilcoxon matched-pairs signed-rank test); and (5) that there were comparable 3-month recurrences. Analyses of COX-2, iNOS, and MVD; metabolic profiles (Western blots); LOH analyses at p53 and fragile histidine triad (FHIT) loci; and p16 promoter methylation studies are ongoing. Our results confirm that BRB constituentsdand not gel base componentsdprovide the chemopreventive activity and demonstrate clinically relevant efficacy. As many key BRB active constituents are redox-active molecules, we speculate that dysplastic phenotype reduction reflects redox-mediated modulation of gene expression and induction of apoptosis. The comparable recurrence rates imply persistence of altered stem cells and suggest a need for sustained treatment.
Clinical Pediatrics, 2007
The aim of the study was to determine if doxycycline causes tooth staining in young children. A d... more The aim of the study was to determine if doxycycline causes tooth staining in young children. A dentist examined 31 randomized children who had been treated with doxycycline and 30 children who had not received doxycycline. Mean age of the children was 10.4 ∓ 2.1 years. Mean age at receipt of the first doxycycline treatment was 4.1 ∓ 1.6 years, and mean number of doxycycline courses was 2.0 ∓ 1.3. No tooth staining was detected by the dentist in any of the children in either group. These findings indicate that treatment with doxycycline in children aged 2 to 8 years is not associated with tooth staining.
Breast Diseases: A Year Book Quarterly, 2009
Electronic-photonic integrated circuits (EPICs) are a promising technology for overcoming bandwid... more Electronic-photonic integrated circuits (EPICs) are a promising technology for overcoming bandwidth and power-consumption bottlenecks of traditional integrated circuits. Silicon is a good candidate for building such devices, due to its high-index contrast and low propagation loss at telecom wavelengths. The current thesis presents recent advances in demonstrating discrete components built in silicon-on-insulator (SOI) platforms, around 1550 nm, that can be used as CONTENTS LIST OF FIGURES .
British Journal of Oral and Maxillofacial Surgery, 1990
ABSTRACT
Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology, 2016
Journal of Craniofacial Surgery