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Biomedical subjects

A B Rabie

Publications and source records attributed to A B Rabie.

At least 19 recordsLinked to original sources
PubMed2005

Identification of temporal pattern of mandibular condylar growth: a molecular and biochemical experiment.

OBJECTIVES: Based on the phenomenon that expression of type X collagen and capillary endothelium correlates with endochondral ossification, the prime aim of this study was to establish the temporal pattern of condylar growth in Sprague-Dawley rats by biochemically identifying the expression of these two factors. DESIGN: Sprague-Dawley rats were divided into five groups representing five different stages during somatic pubertal growth. In situ hybridization and immunoperoxidase were performed to examine expression of type X collagen in hypertrophic zone and capillary endothelium in erosive zone of condylar cartilage. Computer-assisted imaging analyses were conducted to allow for a quantitative assessment of the expression of these two factors, from which the temporal pattern of condylar growth was inferred. RESULTS: (1) Synthesis of type X collagen and emergence of capillary endothelium were critical factors during the transition of condylar cartilage from chondrogenesis into osteogenesis, a biological pathway that leads to endochondral bone formation, the mode through which the condyle grows. (2) Quantitative analyses revealed the temporal pattern of the expression of these two factors, indicating that the thrust of natural growth of the condyle in the rats occurred in concomitance with somatic pubertal growth, featured by an acceleration starting from day 38, a maximum growth rate on day 56, followed by a decrease afterwards. CONCLUSION: It is suggested that the biochemical examination of growth markers, such as type X collagen, might be a new approach to accurately depict temporal pattern of condylar growth which is too delicate to be reflected by gross measurement not only in Sprague-Dawley rats but potentially also in other species.

Animals↗
PubMed2003

[An immunohistochemical study on neovascularization in TMJ during mandibular advancement].

OBJECTIVE: Neovascularization is proved to be closely correlated with ossification. This study was designed to determine the biochemical path through which the new bone formation is enhanced in TMJ during mandibular protrusion. METHODS: SD Rats were fitted with bite-jumping appliances to allow for an adequate advancement of the mandible. The animals were sacrificed 3, 7, 14, 21 and 30 days, respectively, after placement of the appliances. Slides with TMJ tissue were prepared for biochemical procedure. Immunohistochemical approaches were adopted to examine neovascularization in TMJ by immuno-localizing the newly formed endothelial cells. Computer-assisted image analysis system was applied to quantify the positive immunoreaction. RESULTS: Neovascularization in connective tissue close to the condyle was 200% higher in the experimental groups than that in the control, and, within the bony tissue of the condyle, neovascularization in experimental animals was found to be 103% higher than that of the control. CONCLUSION: Increased neovascularization triggered by mandibular protrusion might intensify new bone formation in condyle and glenoid fossa and finally lead to a growth adaptation of TMJ to bite-jumping therapy.

Animals↗
PubMed2001

A comparison of the supra-alveolar pulp size of impeded and unimpeded mandibular rat incisors using micro-computed tomography.

The pulp space is almost totally obliterated in the incisal end of a mandibular rat incisor. Repeated shortening of the incisor has been shown to increase the pulp space below the alveolar bone level; however, little is known about that above the alveolar bone level. This study investigated the changes in the pulp space superior to the bone level after rendering the incisor unimpeded for a period of three weeks. A desktop micro-computed tomography scanning unit, which is non-invasive, non-destructive, accurate, less technique sensitive and less time consuming than conventional methods, was used to calculate the volume of the pulp space. The results showed that the pulp size increased 140% at a level 3 mm below the alveolar bone margin and more than 700% at a level 2.5 mm above the alveolar bone. Moreover, the bone level of the unimpeded incisor was found to move incisally 0.4-0.5 mm; while deposition of dentine on the mesial and distal aspects of the pulp space were affected differently to that on the buccal and lingual sides.

Animals↗
PubMed2001

Osteogenesis in the glenoid fossa in response to mandibular advancement.

The purpose of this study was to identify the temporal sequence of cellular changes in the glenoid fossa and to quantify the amount of bone formation in response to mandibular advancement. One hundred 35-day-old female Sprague-Dawley rats were randomly divided into 5 experimental groups (15 rats each) and 5 control groups (5 rats each). In the experimental groups, functional appliances were used to create continuous forward mandibular advancement. The rats were killed after 3, 7, 14, 21, and 30 days. Sections were cut through the glenoid fossa in the parasagittal plane and stained with periodic acid and Schiff's reagent for evaluation of bone formation and with hematoxylin and eosin for observation of cellular response. The results showed that, in the control rats, bone formation was initially higher in the posterior and middle regions than in the anterior region then decreased over time in all regions. In the experimental group, bone formation significantly increased from day 7 to day 30 compared with control rats. Day 21 marked the highest levels of bone formation in the middle (+184%) and posterior regions (+300%). Mandibular protrusion resulted in the osteoprogenitor cells being oriented in the direction of the pull of the posterior fibers of the disc and also resulted in a considerable increase in bone formation in the glenoid fossa.

Adaptation, Physiological↗
PubMed2001

Patient satisfaction following orthognathic surgical correction of skeletal Class III malocclusion.

The objectives of this study were to evaluate the relationship between preoperative psychologic status and attitude and postsurgical adjustment and experience of the surgical treatment. Questionnaires were sent to 140 consecutive Chinese patients with skeletal Class III malocclusion who had been treated with a combined orthodontic-surgical approach. The results showed the following: (1) immediately after the surgery 44% of patients had more pain, 57% had more numbness, and 73% had more swelling than expected; (2) most patients underwent noted marked changes in facial appearance (96%) and dental appearance (91%); (3) chewing ability improved in 71% of patients; (4) half of those with temporomandibular joint problems preoperatively experienced improvement; (5) personality and lifestyle were affected positively in about 50% of patients; (6) satisfaction with the treatment increased with time: 87% at 6 months and 92% at 24 months; and (7) a few patients (8%) regretted having undergone surgery, mainly because facial changes were not apparent. The vast majority of the present Chinese skeletal Class III patients were satisfied with the overall outcome of the continued orthodontic-surgical treatment.

Attitude to Health↗
PubMed2001

Concerns and motivations of skeletal Class III patients receiving orthodontic-surgical correction.

The objective of this research was to study the impact of skeletal Class III malocclusion on patients' emotional status, as well as patients' motivations for seeking surgical correction of Class III malocclusion. The sample comprised 140 consecutive Chinese patients with skeletal Class III malocclusion who had been treated with a combined orthodontic-surgical approach. A retrospective analysis was performed, based on questionnaires with answers ranked on a numeric scale (O = not at all; 1 = a little; 2 = moderately; 3 = quite a bit; 4 = extremely). Sixty-seven percent of subjects (40 males and 54 females) returned completed questionnaires. Fifty-four percent had bimaxillary deformities, 32% had mandibular hyperplasia, and 14% had maxillary hypoplasia. Seventy-seven percent received bimaxillary surgery, 15% received maxillary advancement, and 8% received mandibular setback. The results showed that nearly half of the patients had a nickname related to their dentofacial problems, and 8 of 10 of these felt embarrassed or angry about their nickname. Ninety-three percent sought improvement of their facial appearance, 85% wanted an improvement in their dental appearance, and 73% desired an improvement in chewing ability. Seventy-six percent were concerned about surgical risks and 63% about possible pain. The vast majority of Class III patients undergoing orthognathic surgery suffered psychologic and functional problems related to their appearance prior to treatment. Esthetic improvement was the driving force behind seeking treatment.

Adolescent↗
PubMed2000

Clinical applications of composite intramembranous bone grafts.

The aim of this article is to introduce the composite intramembranous bone graft mixed with demineralized bone matrix to the clinician and to demonstrate its various clinical applications in the field of clinical orthodontics in the form of case reports. Understanding the mechanism of healing of this composite bone graft provides sound experimental precedent that allows this graft material to become a predictable part of our future orthodontic management. The cases highlighted here took advantage of the several properties of the composite intramembranous demineralized bone matrix graft. An accidental loss of the buccal plate of bone occurred during extraction of a buccally placed premolar for orthodontic purposes. The defect was repaired using chin bone mixed with demineralized bone matrix, and the teeth were successfully moved into the grafted area. A 5-year follow-up showed a stable gingival condition at the grafted area. In this report, ridge augmentation with intramembranous demineralized bone matrix as an adjunct to orthodontic treatment allowed successful placement of endosseous implants. In conclusion, the same graft material was successfully used in the repair of a massive alveolar cleft. Long-term follow-up of these cases showed that this graft is a promising graft material that could be integrated into our orthodontic practice.

Adult↗
PubMed2000

Healing of autogenous intramembranous bone in the presence and absence of homologous demineralized intramembranous bone.

This study was designed to examine the osteogenecity of demineralized bone matrix (DBM) prepared from intramembranous (IM) bone and to quantitatively assess the amount of new bone formed by IM autogenous bone grafts with or without DBM(IM). Forty-two defects were created in 42 New Zealand White rabbits. Twenty-one defects were grafted with IM bone alone, and the other 21 defects were grafted with composite IM-DBM(IM). Eleven rabbits, 22 defects were used as controls, where 11 defects were left empty (passive control) and the other 11 defects were filled with rabbit skin collagen (active control). Tissues were retrieved on days 1, 2, 3, 4, 5, 6, 7, and 14 for qualitative and quantitative analysis. Cells involved in the healing of composite IM and IM-DBM(IM) bone grafts were identified. No cartilage cells were detected during the healing of either grafts. Appearance of small blood vessels into the newly formed matrix was seen on day 5 in IM bone grafts and on day 4 in composite IM-DBM(IM) bone graft. Quantitative analysis was performed by means of image analysis on 100 sections of tissues retrieved after 14 days. Approximately 204% more new bone was formed in defects grafted with composite IM-DBM(IM) than in those grafted with IM bone alone (P <.0001). No bone was formed across the defects in either active or passive controls. In conclusion, DBM(IM) significantly increases the osteogenicity of IM bone grafts.

Analysis of Variance↗
PubMed2000

Diagnostic criteria for pseudo-Class III malocclusion.

The aim of this study is to identify the diagnostic criteria for pseudo-Class III malocclusion and compare it with Class I malocclusion in the southern Chinese population. Sixty-seven patients (mean age, 10.9 +/- 1.8 years) were included in this study; 36 patients represented pseudo-Class III malocclusion. Selection criteria included the following: (1) anterior crossbite (at least 2 incisors with negative overjet and overbite); (2) mandibular displacement; (3) all patients were southern Chinese who had been followed after the growth spurt, none had developed a skeletal Class III malocclusion; (4) the patients were treated for an average of 7 months to procline upper incisors and retrocline lower incisors. None of the cases received any treatment that might affect skeletal growth. Thirty-one patients with Class I malocclusion were included in the Class I malocclusion group for the comparison of dentoskeletal characteristics with the pseudo-Class III malocclusion group. Selection criteria included the following: (1) skeletal Class I malocclusion with normal overjet and overbite, (2) mild to moderate crowding with Class I molar relationship, (3) straight facial profile. The following were included in the assessment of pseudo-Class III malocclusion cases: (1) family history, (2) molar and canine relationships at habitual occlusion and centric relation, and (3) dentoskeletal morphology. The results were that 72% of the examined cases in the pseudo-Class III malocclusion group showed no family history and 75% showed Class I molar relationship at habitual occlusion. Compared with the Class I malocclusion group, subjects in the pseudo-Class III malocclusion group showed a significantly decreased midface length, increased maxillary-mandibular difference, more retroclined upper incisors, and a retrusive upper lip. In conclusion, a pseudo-Class III malocclusion is characterized by retroclined upper incisors, retrusive upper lip, decreased midface length, and increased maxillary-mandibular difference. Findings of this study showed that patients with a pseudo-Class III malocclusion exhibit certain morphologic, dental, and skeletal characteristics that should be of aid in the diagnosis of pseudo-Class III malocclusion.

Centric Relation↗
PubMed2000

Composite autogenous bone and demineralized bone matrices used to repair defects in the parietal bone of rabbits.

We compared the amount of new bone produced by endochondral and intramembranous autogenous bone grafts in the presence of demineralized bone matrices (DBMs) prepared from intramembranous bone (DBM(IM)) or endochondral bone (DBM(EC)). Thirty-five bone defects were created in the parietal bone of 20 New Zealand White rabbits. In the experimental groups, 5 defects were grafted with endochondral bone, 5 with endochondral bone mixed with DBM(IM)) (EC-DBM(IM)), 5 with intramembranous bone mixed with DBM(IM)(IM-DBM(IM)) and 6 with endochondral bone mixed with DBM(EC)(EC-DBM(EC)). In the control groups, 10 defects were left alone (passive control) and 4 were grafted with rabbit skin collagen (active control). They were all killed on day 14 and the defects were prepared for histological study. Serial sections were cut across the whole defect. Quantitative analyses were made on 202 sections of the experimental groups by image analysis. A total of 414%, 708%, and 85% more new bone was formed in defects grafted with composite EC-DBM(IM), IM-DBM(IM)and EC-DBM(EC), respectively, than those grafted with endochondral bone alone (P<0.001). No bone was formed in either passive or active controls. In conclusion, demineralized bone matrices, particularly those derived from intramembranous bone, have extremely high osteoinductive properties and greatly improve the integration of autogenous bone grafts in the skull.

Analysis of Variance↗
PubMed2000

Vascular endothelial growth pattern of endochondral bone graft in the presence of demineralized intramembranous bone matrix--quantitative analysis.

OBJECTIVE: To determine the timely ingrowth of new blood vessels of composite endochondral (EC) bone and demineralized bone matrix (DBM) prepared from intramembranous (IM) origin (EC-DBM(IM)) and to compare it with EC bone graft alone. DESIGN: Thirty-two rabbits with 32 critical-size (10 x 5 mm), full-thickness bony defects in rabbit parietal bone were divided into two groups: composite EC-DBM(IM) group-implanted with composite autogenous EC bone and DBM(IM); EC bone group-implanted with EC bone alone. Two rabbits from each group were sacrificed-1, 2, 3, 4, 5, 6, 7, and 14 days after grafting. Neovascularization was assessed by immunohistochemical staining with antihuman angiogenesis-related endothelial cell antibodies (EN 7/44). Quantitative analysis of neovascularization, represented by percentage area of positive immunohistochemical staining, was performed on 320 sections of the experimental groups by a computer-assisted image analyzer. RESULTS: Positive immunohistochemical staining was first identified on day 2 post grafting for the composite EC-DBM(IM) group in comparison with day 4 in the EC bone graft group. The composite EC-DBM(IM) bone graft group showed earlier and almost 100% more neovascularization when compared with the EC bone graft group. CONCLUSION: DBM(IM) enhances healing and integration of EC bone graft by enhancing vascularization as well as increasing the amount of new blood vessels formed. In clinical cases in which EC autogenous bone is used to graft a large defect such as in cleft palate and craniofacial surgery, DBM(IM) should allow better integration and healing of the EC bone graft to the host bone.

Animals↗
PubMed2000

Treatment effects of simple fixed appliance and reverse headgear in correction of anterior crossbites.

The aim of this study was to compare the skeletal and dental changes contributing to the correction of Class III malocclusion using a 2 x 4 appliance and reverse headgear in the mixed dentition. Seventeen consecutive patients (mean age, 9.7 years) with pseudo-Class III malocclusions and an anterior functional shift and straight or concave facial profile were treated with a simple fixed appliance. Another 20 consecutive patients (mean age, 8.5 years) with Class III incisor relationship and straight or concave facial profiles, were treated with reverse headgear. Lateral cephalometric films taken at the beginning of treatment, the end of the treatment, and 1 year after the active treatment, were analyzed with the modified Pancherz analysis. After active treatment, the overjet correction, 5.2 mm and 6.5 mm on average, respectively, were achieved using the 2 x 4 and reverse headgear. The overjet correction by the 2 x 4 appliance was due to dental changes only. In the reverse headgear group, 60% of the overjet correction was due to dental changes and 40% due to skeletal changes. During the 12 months follow-up period, the overjet was unchanged in the 2 x 4 group (1.6 mm) and decreased in the reverse headgear group, the difference being statistically significant (P <.05). The change of jaw relationship was similar between the 2 x 4 and reverse headgear groups. During the follow-up period, a decrease in overjet in the reverse headgear group was mainly due to forward growth of the mandible and proclination of lower incisors. The overjet in the 2 x 4 group was unchanged due to dental compensation (1.6 mm). To conclude there was a similar amount of overjet correction in the 2 x 4 and reverse headgear groups. Overjet correction by the simple fixed appliance was produced by dental changes whereas in the reverse headgear group, it was produced by both dental and skeletal changes.

Cephalometry↗
PubMed2000

Dental changes and space gained as a result of early treatment of pseudo-Class III malocclusion.

This study was designed to investigate the dental changes and the space gained following early treatment of pseudo-Class III malocclusion, using a simple fixed appliance. Twenty-one consecutively treated patients who had a pseudo-Class III malocclusion comprised the treated group. Fifteen untreated control subjects were used as matched controls for the three-year follow-up after completion of treatment. Lateral cephalograms and study models were analysed for the treated, the control and the follow-up group. The arithmetic mean and standard deviation were calculated for each variable, and paired t-tests were performed to assess the effects of treatment on the treated group. The Mann-Whitney test was performed to evaluate the difference between the follow-up group and the control group. Anterior crossbites and mandibular displacements were eliminated after the treatment. On average, the space gained as a result of the treatment was 4.7 mm in the upper arch (p < 0.001 degree). Comparison of the space available as a result of early treatment with the space required for alignment of posterior segments in the upper arch of the untreated control group indicated that there was enough space for the eruption of the canines and premolars as a result of early treatment; whereas, lack of space was evident in the untreated controls. In conclusion, a pseudo-Class III malocclusion, proclination of the upper incisors and/or retroclination of the lower incisors contributed to the correction of anterior crossbite and the elimination of mandibular displacement. Proclination of the upper incisors, utilisation of leeway space, and arch-width increase provided the space required for eruption of the premolars and canines.

Bicuspid↗
PubMed2000

Ultrastructural identification of cells involved in the healing of intramembranous bone grafts in both the presence and absence of demineralised intramembranous bone matrix.

Alveolar bone defects are conditions that impede the progress of orthodontic treatment. This study compared the mechanics of the healing of autogenous intramembranous (IM) bone grafts and grafts comprising a mixture of IM and demineralised bone matrix of autogenous intramembranous origin (DBMIM), in an attempt to determine the reliability of each material. Thirty-two New Zealand white rabbits had a single defect created in their skull. Sixteen were grafted with IM bone alone (Group I: autogenous IM), and the other 16 had a combined graft of composite IM sandwiched between two layers of DBMIM (Group II: composite IM-DBMIM). A third group (Group III) of eight rabbits each had two defects created in their skull; one defect was left empty (A: passive control) and the other filled with rabbit-skin collagen (B: active control). In Groups I and II, inflammatory cells were found to be present on Days 1 and 2 of tissue retrieval. The appearance of the mesenchymal cells and preosteoblasts, osteoblasts and osteocytes was earlier (Day 3) in Group II than in Group I (Day 5). In both groups, preosteoblasts, osteoblasts and osteocytes were observed with no cartilage at the intermediate stage. In conclusion, autogenous IM bone grafts and IM bone grafts in the presence of DBMIM healed through an osteogenic ossification route.

Animals↗
PubMed2000

[Expression of type X collagen in condylar cartilage during mandibular protrusion].

OBJECTIVE: This study was designed to detect type X collagen expression, at both gene and protein levels, in condylar cartilage during mandibular protrusion triggered by functional appliance. METHODS: One hundred SD rats with age of 5 weeks were selected and divided into 5 experimental groups (n = 5) and 5 control groups (n = 5). Animals in experimental groups were imposed with bite-jumping appliances which caused identical magnitude of mandibular protrusion. The animals of experimental groups, together with their matched controls, were sacrificed 3, 7, 14, 21 and 30 days after the appliance insertion. 6 microns sections were cut from TMJ through the sagittal plane. In situ hybridization and immunohistochemical analysis were performed to detect the expression of type X collegen mRNA transcription and its protein synthesis. RESULTS: 1. Intensive staining of type X collegen mRNA was found to distribute within the whole area of hypertrophic zone, a sharp contrast to the control groups which showed very little or no staining. 2. Type X collegen protein synthesis, which was highlighted by immunofluoscent staining, was found to spread over the whole hypertrophic zone, compared to the controls that demonstrated a very little staining. CONCLUSION: Expression of type X collagen in condylar cartilage indicates the onset of endochondral ossification in condyle in response to mandibular protrusion provoked by functional appliances.

Animals↗