Ability of piezocision to retain orthodontically moved teeth in a goat model: A split-mouth study.

OBJECTIVES: to evaluate the effectiveness of piezocision in enhancing retention when performed after orthodontic tooth movement. METHODS: Four mature goats had their second incisors removed bilaterally. For each goat, the two sides of the mandible were either treated with piezocision or served as a positive control. Using fixed orthodontic appliance, the first and third incisors on each side were approximated and then retained in place for two weeks. Relapse was measured by the amount of space developed between the approximated incisors after six weeks from the end of the retention period. The periodontal ligament of all incisors was assessed histologically with micro computed tomography and regular hematoxylin and eosin staining. RESULTS: A significantly less relapse was observed in the piezocision group than in the control group (p ≤ 0.05). Bone formation occurs in the vicinity and periphery of the periodontal ligament and thus results in the narrowing of the periodontal ligament. CONCLUSION: A protocol of post-orthodontic retention involving piezocision can be promising to enhance stability of orthodontic treatment outcome.

Utility of injectable bisphosphonates in enhancing orthodontic retention in a goat model: A split-mouth study.

Objective: The aim of this study was to evaluate the utility of bisphosphonates in reducing relapse after orthodontic tooth movement when injected intra-periodontally in a goat model. Methods: Right and left second incisors of four goats were extracted and the first and third incisors were approximated orthodontically and retained. A bisphosphonate gel was injected into the mesial and distal periodontal spaces of first and third incisors on one side, while the first and third incisors of the other side received normal saline as a control. After 12 weeks of retention, the orthodontic appliance was removed and teeth were relieved from any active force. Following 6 weeks from appliance removal, millimetric measurements were performed to calculate the amount of relapse of orthodontically moved incisors. Histological and microcomputed tomographic examination was performed to assess the periodontal space and surrounding alveolar bone of the study and control incisors. Results: The millimetric measurements and microcomputed tomographic scanning revealed that the orthodontically moved incisors in the side of bisphosphonate injection had significantly less relapse (p ≤ 0.05) and significantly narrower periodontal ligament width (p ≤ 0.05) than in the control side, respectively. Histologically, newly formed bone projecting into the periodontal ligament was observed in the side of bisphosphonate injection with newly formed cementum overlying areas of resorbed cementum. Conclusion: The results suggest that bisphosphonate injection has the potential to enhance post-orthodontic stability and repair of root resorption following orthodontic treatment.

The effect of low intensity pulsed ultrasound on dentoalveolar structures during orthodontic force application in diabetic ex-vivo model.

OBJECTIVE: This study aimed to investigate the effect of the low intensity pulsed ultrasound (LIPUS) on the dentoalveolar structures during orthodontic force application in ex-vivo model using mandible slice organ culture (MSOC) of diabetic rats. DESIGN: 18 male Wistar rats with a mean weight (275 g) were randomly divided into three main groups: 1) normal rats, 2) Insulin treated diabetic rats, and 3) diabetic rats. Diabetes mellitus (DM) was induced by streptozotocin. Four weeks later, rats were euthanized, mandibles were dissected, divided into 1.5-mm slices creating mandible slice organ cultures (MSOCs). MSOCs were cultured at 37 °C in air with 5 % CO2. The following day, orthodontic spring delivering a 50-g of force was applied to each slice. In each group, rats were randomly assigned to 2 subgroups; one received 10 min of LIPUS daily and the other was the control. Culture continued for 7 days, and then the sections were prepared for histological and histomorphometric analysis. RESULTS: For all study groups (Normal, Insulin Treated Diabetic and Diabetic), LIPUS treatment significantly increased the thickness of predentin, cementum, and improved bone remodeling on the tension side and increased odontoblast, sub-odontoblast, and periodontal ligaments cell counts and bone resorption lacunae number on the compression side. CONCLUSIONS: Application of LIPUS treatment for 10 min daily for a week enhanced bone remodeling and repair of cementum and dentin in normal as well as diabetic MSOCs.

Assessment of knowledge and attitude toward stem cells and their implications in dentistry among recent graduates of dental schools in Saudi Arabia.

BACKGROUND: To evaluate the knowledge and attitude level of recent dental graduates in Saudi Arabia toward stem cells and their potential therapeutic applications. METHODS: In this cross-sectional study, a questionnaire was distributed among 606 recent graduates from 14 dental schools in Saudi Arabia. Fifteen statements were formulated to address the knowledge component with "yes" or "no" or "I do not know" answer and 10 statements were designed to assess the attitude level with Likert 5-point response scale. The level of knowledge for each respondent was designated as poor if the score value is (0-5), moderate (6-10), and high (11-15). To evaluate the attitude level for each respondent, a score of (1) was assigned for extremely negative answer and (5) for extremely positive answer for each statement. Based on the total score, attitude level was considered poor when the score value is (10-29), moderately positive (30-39), good (40-44), or excellent (45-50). RESULTS: Significant difference was found in the knowledge score between males and females (p = 0.004). Both males and females showed poor knowledge with a mean score of 5.06 ±â€¯2.5 and 5.63 ±â€¯2.4, respectively. There was an overall moderately positive attitude of participants toward stem cells and their therapeutic applications with a mean value of 33.15 ±â€¯5.92 with no significant difference between males and females (p = 0.53). A significant positive linear correlation was detected between knowledge and attitude for both males (r = 0.323, p = 0.00) and females (r = 0.392, p = 0.00). CONCLUSION: Updating dental curricula with topics on stem cell research and potential future applications in dentistry is demanded.

Comparative tomographic study of the maxillary central incisor collum angle between Class I, Class II, division 1 and 2 patients.

INTRODUCTION: It has been reported that Class II, division 2 maxillary central incisors frequently demonstrate increased collum angles, which indicates an excessive palatal "bend" of the crown. However, evidence supporting such observation is mostly derived from radiographic studies. OBJECTIVE: The objective of this study was to evaluate and compare the collum angle of maxillary central incisors in Class I, Class II, division 1, and Class II, division 2 cases using cone-beam computed tomography. MATERIALS AND METHODS: Forty-eight consecutive orthodontic cases (16 Class I, 16 Class II, division 1, and 16 Class II, division 2 malocclusion) with cone-beam computed tomography as part of their initial diagnostic records were evaluated. Cross-sections including maxillary right and left central incisors were used to calculate the angulation between the crown and root long axes (collum angle). Comparisons between groups were performed using analysis of variance for multiple and post-hoc Tukey for paired analyses. RESULTS: Mean collum angle observed in Class II, division 2 cases was significantly larger (5.2 ± 1.3°) than the ones obtained for Class I (1.1 ± 4.2°) (P = 0.034) or Class II, division 1 cases (0.1 ± 0.7°) (P = 0.014). CONCLUSIONS: Our findings suggest that Class II, division 2 individuals demonstrate accentuated lingual inclination of the maxillary central incisor crown compared to the other types of malocclusion studied here. Such morphological feature indicates the need for better tooth movement planning, especially in regard to root palatal torqueing of the maxillary central incisors.

Association between anterior alveolar dimensions and vertical facial pattern among Saudi adults.

OBJECTIVE: To establish the anterior alveolar dimensions among a sample of Saudi subjects with different vertical facial heights. MATERIALS AND METHODS: Lateral cephalometric radiographs of 63 Saudi subjects (30 males and 33 females) were included in this retrospective study. The sample was divided into high angle (SN-MP â©¾ 39°), low angle (SN-MP â©½ 28°) and average angle (30° < SN-MP < 37°) groups. The anteroposterior and vertical dimensions of the alveolus surrounding the root apex of upper and lower incisors were calculated. RESULTS: The anterior alveolar dimensions exhibited significant differences (p < 0.05) between the different vertical facial height groups. The males and females demonstrated significant differences (p < 0.05) in the anterior alveolar dimensions for the same vertical jaw relationship. CONCLUSIONS: Both gender and the vertical jaw relationship can be factors for different height and thickness of the anterior alveolus. Clinicians must be aware of differences in the anterior alveolar dimensions for safe and sound orthodontic tooth movement.

Anchorage condition during canine retraction using transpalatal arch with continuous and segmented arch mechanics.

OBJECTIVE: To compare anchorage condition in cases in which transpalatal arch was used to enhance anchorage in both continuous and segmented arch techniques. MATERIALS AND METHODS: Twenty cases that required first premolar extraction for orthodontic treatment and transpalatal arch to enhance anchorage were included in this study. Ten cases were treated using the continuous arch technique, while the other 10 cases were treated using 0.019 × 0.025-inch TMA T-loops with posterior anchorage bend according to the Burstone and Marcotte description. Lateral cephalometric analysis of before and after canine retraction was performed using Ricketts analysis to measure the anteroposterior position of the upper first molar to the vertical line from the Pt point. Data were analyzed using an independent sample t-test. RESULTS: There was a statistically significant forward movement of the upper first molar in cases treated by continuous arch mechanics (4.5 ± 3.0 mm) compared with segmented arch mechanics (-0.7 ± 1.4 mm; P  =  .01). CONCLUSIONS: The posterior anchorage bend to T-loop used to retract the maxillary canine can enhance anchorage during maxillary canine retraction.

Controlled release of injectable liposomal in situ gel loaded with recombinant human bone morphogenetic protein-2 for the repair of alveolar bone clefts in rabbits.

BACKGROUND AND OBJECTIVE: The aim of the present study was to develop and examine a new non-invasive injectable graft for the repair of alveolar bone clefts using recombinant human bone morphogenetic protein-2 (rhBMP-2) encapsulated within injectable liposomal in situ gel (LIG). METHOD: Different liposomal formulations loaded with rhBMP-2 were prepared, and the effects of the preparation methods and lipid content on the efficiency of rhBMP-2 encapsulation within the liposomes were studied. For the preparation of in situ gel, deacetylated gellan gum (DGG) was used, and the in vitro gelation characteristics of the gel were evaluated. In vivo pharmacokinetics and histology were also assessed. Critical size alveolar defects were surgically created in the maxillae of 30 New Zealand rabbits and treated with different injectable formulae, including rhBMP-2 liposomes and in situ gel (rhBMP-2-LIG). RESULTS: The results indicated that the prepared rhBMP-2-LIG prolonged the release and residence time of BMP-2 within rabbits for more than 7 days. Histomorphometric assessment showed 67% trabecular bone filling of the defects treated using this novel formula. CONCLUSION: BMP-2-LIG is a promising delivery device for the repair of alveolar bone defects associated with cleft deformities.

Rapid maxillary expansion effects in Class II malocclusion: a systematic review.

OBJECTIVE: To evaluate the effectiveness of rapid maxillary expansion (RME) on the sagittal dental or skeletal parameters of growing children with Class II malocclusion. MATERIALS AND METHODS: A systematic review intended to identify relevant literature was conducted. The search was performed on Medline, Embase, Cochrane Library, and Scopus databases. Reference lists of the included articles were also screened for relevant documents. The qualitative assessment was performed according to the Methodological Index for Non-Randomized Studies (MINORS) tool, and the resultant data were grouped and analyzed concerning dental and skeletal sagittal effects of RME. RESULTS: Of 25 screened studies, seven articles met eligibility criteria and were included. Study samples were observed during mixed dentition stage and characterized as having either Class II dental malocclusion or skeletal discrepancy. None of the included studies was a randomized clinical trial. Included controlled studies presented several inadequacies related to control group or lacked appropriate comparative statistical analysis. Besides being frequently based on deficient methodology, dental and skeletal sagittal effects of RME were either controversial or lacked clinical relevance. CONCLUSION: The effect of RME on the sagittal dimension of Class II malocclusions has not been proved yet. Future randomized controlled clinical trials are still needed to definitely address this question.

Biomarkers of Orthodontic Tooth Movement in Gingival Crevicular Fluid: A Systematic Review.

BACKGROUND: The analysis of gingival crevicular fluid (GCF) may be an acceptable way to examine the ongoing biochemical processes associated with bone turnover during orthodontic tooth movement. If it is possible to biologically monitor and predict the outcome of orthodontic forces, then the management of appliances could be based on individual tissue responses, and the effectiveness of the treatment could be improved. METHODOLOGY: A literature search was carried out in major databases, such as medline, EMBASE, cochrane library, web of science, google scholar and scopus for relevant studies. Publications in English between 2000 and 2014 which estimated GCF markers as indicators of orthodontic tooth movement were included. RESULTS: The list of biomarkers available to date was compiled and presented in table format. Each biomarker is discussed separately based on the available evidence. CONCLUSION: Several sensitive GCF markers are available to detect the biomechanical changes occurring during orthodontic tooth movement. Further focused research might help to analyze the sensitivity and reliability of these indicators, which in turn can lead to the development of chairside tests to assess the outcome of orthodontic therapy.

Depot injectable biodegradable nanoparticles loaded with recombinant human bone morphogenetic protein-2: preparation, characterization, and in vivo evaluation.

OBJECTIVE: The aim of this study is to utilize the biocompatibility characteristics of biodegradable polymers, viz, poly lactide-co-glycolide (PLGA) and polycaprolactone (PCL), to prepare sustained-release injectable nanoparticles (NPs) of bone morphogenetic protein-2 (BMP-2) for the repair of alveolar bone defects in rabbits. The influence of formulation parameters on the functional characteristics of the prepared NPs was studied to develop a new noninvasive injectable recombinant human BMP-2 (rhBMP-2) containing grafting material for the repair of alveolar bone clefts. MATERIALS AND METHODS: BMP-2 NPs were prepared using a water-in-oil-in-water double-emulsion solvent evaporation/extraction method. The influence of molar ratio of PLGA to PCL on a suitable particle size, encapsulation efficiency, and sustained drug release was studied. Critical size alveolar defects were created in the maxilla of 24 New Zealand rabbits divided into three groups, one of them treated with 5 µg/kg of rhBMP-2 NP formulations. RESULTS: The results found that NPs formula prepared using blend of PLGA and PCL in 4:2 (w/w) ratio showed the best sustained-release pattern with lower initial burst, and showed up to 62.7% yield, 64.5% encapsulation efficiency, 127 nm size, and more than 90% in vitro release. So, this formula was selected for scanning electron microscope examination and in vivo evaluation. Histomorphometric analysis showed 78% trabecular bone fill, mostly mature bone in the defects treated with rhBMP-2 in NPs within 6 weeks. CONCLUSION: The prepared NPs prolonged the release and the residence time of rhBMP-2 in rabbits, which led to the formation of adequate bone in critical size alveolar bone defects in 6 weeks. This noninvasive method has application for the primary restoration of alveolar bone defects.

Ability of admissions criteria to predict early academic performance among students of health science colleges at King Saud University, Saudi Arabia.

The aim of this study was to evaluate the ability of admissions criteria at King Saud University (KSU), Riyadh, Saudi Arabia, to predict students' early academic performance at three health science colleges (medicine, dentistry, and pharmacy). A retrospective cohort study was conducted with data from the records of students enrolled in the three colleges from the 2008-09 to 2010-11 academic years. The admissions criteria-high school grade average (HSGA), aptitude test (APT) score, and achievement test (ACT) score-were the independent variables. The dependent variable was the average of students' first- and second-year grade point average (GPA). The results showed that the ACT was a better predictor of the students' early academic performance than the HSGA (ß=0.368, ß=0.254, respectively). No significant relationship was found between the APT and students' early academic performance (ß=-0.019, p>0.01). The ACT was most predictive for pharmacy students (ß=0.405), followed by dental students (ß =0.392) and medical students (ß=0.195). Overall, the current admissions criteria explained only 25.5% of the variance in the students' early academic performance. While the ACT and HSGA were found to be predictive of students' early academic performance in health colleges at KSU, the APT was not a strong predictor. Since the combined current admissions criteria for the health science colleges at KSU were weak predictors of the variance in early academic performance, it may be necessary to consider noncognitive evaluation methods during the admission process.

The effect of light-emitting diode and laser on mandibular growth in rats.

OBJECTIVE: To evaluate the effect of a light-emitting diode (LED) and/or low-level laser (LLL) with or without the use of anterior bite jumping appliances (also known as functional appliances [FAs]) on mandibular growth in rats. MATERIALS AND METHODS: Thirty-six 8-week-old male Sprague-Dawley rats weighing 200 g were obtained from Charles River Canada (St. Constant, QC, Canada) and were divided into six groups of six animals each. Groups were as follows: group 1: LLL; group 2: LLL + FA; group 3: LED; group 4: LED + FA; group 5: FA; and group 6: control (no treatment). Mandibular growth was evaluated by histomorphometric and micro computed tomographic (microCT) analyses. RESULTS: The LED and LED + FA groups showed an increase in all condylar tissue parameters compared with other groups. CONCLUSION: The LED-treated groups showed more mandibular growth stimulation compared with the laser groups.

Comparison of two three-dimensional cephalometric analysis computer software.

BACKGROUND: Three-dimensional cephalometric analyses are getting more attraction in orthodontics. The aim of this study was to compare two softwares to evaluate three-dimensional cephalometric analyses of orthodontic treatment outcomes. MATERIALS AND METHODS: Twenty cone beam computed tomography images were obtained using i-CAT(®) imaging system from patient's records as part of their regular orthodontic records. The images were analyzed using InVivoDental5.0 (Anatomage Inc.) and 3DCeph™ (University of Illinois at Chicago, Chicago, IL, USA) software. Before and after orthodontic treatments data were analyzed using t-test. RESULTS: Reliability test using interclass correlation coefficient was stronger for InVivoDental5.0 (0.83-0.98) compared with 3DCeph™ (0.51-0.90). Paired t-test comparison of the two softwares shows no statistical significant difference in the measurements made in the two softwares. CONCLUSIONS: InVivoDental5.0 measurements are more reproducible and user friendly when compared to 3DCeph™. No statistical difference between the two softwares in linear or angular measurements. 3DCeph™ is more time-consuming in performing three-dimensional analysis compared with InVivoDental5.0.

Ultrasound effect on neural differentiation of gingival stem/progenitor cells.

Dental pulp loss due to caries or pulpitis can affect the longevity of teeth. Dental pulp tissue engineering necessitates the use of progenitor cells that has the potential to differentiate into neural, vascular and odontoblasts like cells. Previous reports have shown that human gingival progenitor cells (HGPCs) can be differentiated into different cell types; however neural differentiation of these cells, to the best of our knowledge, has not been reported. Low intensity pulsed ultrasound (LIPUS) has been reported to enhance cell differentiation. The aims of this study were (1) to explore the potential neural differentiation of HGPCs and (2) to investigate the effect of LIPUS on the differentiation of HGPCs when incubated under neuroinductive conditions. The HGPCs were isolated from human interdental papilla proximal to the premolar teeth that were extracted for orthodontic purpose. The HGPCs were induced to differentiate into neural lineage using a neuroinductive culture medium. HGPCs were divided into four groups; control group, neuro-induction (NI) group, ultrasound group (LIPUS), and a combined NI+LIPUS group. HGPCs were harvested for immunostaining and q-PCR after 1 day. Immunostaining for neuron specific antigens and q-PCR suggested that HGPCs can be differentiated into neural lineage and that selected neurodifferentiation markers can be enhanced by LIPUS.

New therapeutics in promoting and modulating mandibular growth in cases with mandibular hypoplasia.

Children with mandibular growth deficiency may develop airway obstruction. The standard treatment of severe airway obstruction involves invasive procedures such as tracheostomy. Mandibular distraction osteogenesis has been proposed in neonates with mandibular deficiency as a treatment option to avoid tracheostomy procedure later in life. Both tracheostomy and distraction osteogenesis procedures suffer from substantial shortcomings including scarring, unpredictability, and surgical complications. Forward jaw positioning appliances have been also used to enhance mandible growth. However, the effectiveness of these appliances is limited and lacks predictability. Current and future approaches to enhance mandibular growth, both experimental and clinical trials, and their effectiveness are presented and discussed.

New method for evaluation of cervical vertebral maturation based on angular measurements.

OBJECTIVE: To investigate the validity of a new approach to assess the cervical vertebral maturation based on angular measurements of the lower border concavity of cervical vertebral bodies. METHODS: Hand-wrist and lateral cephalometric radiographs of 197 male subjects with age range of 10-15 years attending the orthodontic clinic at King Saud University, Riyadh, Kingdom of Saudi Arabia were utilized. The study was carried out between September 2009 and May 2011. The study sample was divided into 6 groups (group 1: 10 years to group 6: 15 years) based on the chronological age of the subject. The skeletal age of the subjects was determined using Greulich and Pyle's standard radiographic atlas, and skeletal maturation was assessed by Fishman's skeletal maturity indicators. The cervical vertebral maturation (CVM) of subjects was determined using angular measurements of the second, third, and fourth cervical vertebral bodies. The validity of the newly developed method was assessed by examining the correlation between CVM stages determined by the angular measurements and the skeletal maturation level as determined by the standard hand-wrist methods. RESULTS: A significant correlation (r=0.94) was found between the angular CVM stages and the skeletal age determined by Greulich and Pyle's atlas from hand-wrist radiographs. Also, a high correlation (r=0.94) was found between the angular CVM stages and the Fishman's hand-wrist skeletal maturity indicators. CONCLUSION: The new angular measurement approach to determine CVM is valid and has the potential to be applied in assessing skeletal maturity level in growing male children.

Effect of therapeutic ultrasound on human periodontal ligament cells for dental and periodontal tissue engineering.

The objective of this study was to investigate whether low intensity pulsed ultrasound (LIPUS) has anabolic effects on human periodontal ligament (PDL) cells. The PDL cells were plated in 48-well plates and cultured at 37°C in an atmosphere of 5% CO2 in air, in a humidified incubator until confluent. The cells were divided into three groups including control, 5 min and 10 min ultrasound application. The LIPUS was applied using a 2.5 transducer that produces an incident intensity of 30 mW/cm2 of the transducer's surface area. The results from the quantitative polymerase chain reaction (PCR) indicates that expression levels of alkaline phosphatase (ALP),cyclin D1 (CYC), nucleostemin (NCT) were increased after four weeks of 10 minutes of daily ultrasound treatment. The increased ALP/DNA by LIPUS shows a time dependent pattern with the highest activity occurring after four weeks of treatment. These results demonstrate that LIPUS has an anabolic effect on PDL cells and suggest that LIPUS may enhance the pluripotent characteristics of PDL cells as indicated by the up-regulation of NCT, a stem marker. These results also may explain the potential role of LIPUS in periodontal tissue regeneration.

Anterior alveolar dimensions among different classifications of sagittal jaw relationship in Saudi subjects.

UNLABELLED: Sound orthodontic movement of anterior teeth is delineated by the biological dimensions of the anterior alveolus. OBJECTIVE: To establish and compare the anterior alveolar dimensions among normal and abnormal sagittal maxillomandibular relationships in a Saudi sample. MATERIALS AND METHODS: The lateral cephalometric radiographs of 81 Saudi subjects (42 males and 39 females) were used to determine the anteroposterior and vertical dimensions of the anterior alveolus in Class I (N = 30), Class II (N = 24), and Class III (N = 27) cases. The anterior alveolar dimensions were then compared among males and females belonging to the same sagittal classification and between the different sagittal classifications of the same gender. RESULTS: Significant differences (P < 0.05) in the anterior alveolar dimensions between males and females were demonstrated for the same sagittal jaw classification. Also, significant differences (P < 0.05) were detected between the anterior alveolar dimensions among the different sagittal maxillomandibular classifications of the same gender. CONCLUSION: Both the gender and the sagittal maxillomandibular relationship can affect the anteroposterior and vertical dimensions of the anterior alveolus.