Comparative Evaluation of Digital and Conventional Workflows for the Fabrication of Multi-Unit Implant-Supported Fixed Restorations: An Empty Review.

Objectives: This study aimed to do a comprehensive systematic review on the comparison of digital and conventional workflows regarding prosthetic outcomes, accuracy of implant impressions, framework passivity and fit, and clinical fabrication of multi-unit implant-supported fixed restorations. Materials and Methods: The EMBASE, PubMed, Scopus, and Cochrane Library databases were searched for relevant articles published up until April 2020. Results: No in-vivo article was found to compare full digital and conventional workflows regarding the accuracy of implant impressions, passivity and fit of frameworks, and prosthetic outcomes. There was no study to investigate full digital and conventional workflows for clinical fabrication of multi-unit implant-supported fixed restorations. Conclusion: This empty review highlights the need for further research to compare full digital and conventional workflows for implant-supported restorations.

Peri-implant bone alterations under the influence of abutment screw preload stress. A preclinical vivo study.

OBJECTIVES: The study purpose was to examine peri-implant bone alternations around osseointegrated implants caused solely by abutment screw preload stress using different tightening torque values. MATERIALS AND METHODS: Twenty 20- to 22-week-old Japanese white rabbits received two implants each in right and left femurs. Implants were randomly assigned to one of three tightening torque groups or the control (Cont) group. After 8 weeks, 35 Ncm torque was delivered to abutment screws in the recommended torque (RT) group (n = 16). Other screws received 70 Ncm torque as the high torque (HT) group (n = 16). Temporary tightening (TT) groups (n = 8) received only 70 Ncm torque without preload stress as screws were untightened immediately. Cont group (n = 40) remained in situ. Animals were euthanized at 4, 6, 8, and 10 weeks after torque application. Micro-CT images were then taken, and undecalcified ground sections were stained with toluidine blue. RESULTS: Cross-sections of cortical bone showed remodeling activities adjacent to the implant in all groups. While bone marrow spaces appearance was relatively small in Cont and TT groups, RT and HT groups showed large bone marrow spaces and extensive remodeling activity. Bone-to-implant contact was significantly less in RT and HT groups compared with Cont and TT groups at different time points (p Ë‚ .05). Furthermore, RT and HT groups showed significantly less bone volume and area (p Ë‚ .05). CONCLUSION: Results suggested that preload stress without any occlusal loading might negatively affect peri-implant bone stability and initiate bone remodeling. This could alter bone mechanical properties, subsequently influencing long-term implant success.

Use of High Performance Polymers as Dental Implant Abutments and Frameworks: A Case Series Report.

Dental implant abutments can be made of different materials including titanium, gold, zirconia, alumina, and polymeric materials. Polyetheretherketone (PEEK) is a high performance thermoplastic polymer that can be used as a dental implant abutment material. It has an elastic modulus comparable to bone and can reduce stress shielding. PEEK is a radiolucent material that can allow better radiographic imaging of peri-implant tissues and can be veneered with composite materials or bonded to ceramics. PEEK is widely used in orthopedic and spinal surgeries, and it possesses mechanical and biological characteristics that encourage its use as dental implant abutments. This article will review the use of PEEK in dentistry and in particular as a dental implant abutment and over implant framework. Clinical reports will be presented to suggest some uses of PEEK materials in implant dentistry.

The mental foramen: A cone beam CT study of the horizontal location, size and sexual dimorphism amongst living Jordanians.

Accurate information regarding the horizontal location and size of mental foramen (MF) has a well-known clinical importance. In addition, these variables have been reported to exhibit inter-population variation. The aims of the present study were to study the horizontal position and size of MF, as seen on cone beam CT (CBCT) images, and to assess sexual dimorphism in these variables. Total of 139 CBCT images of a random Jordanian sample (50 males, 89 females, average age = 43.5, SD = 13.0, range = 23-69 years) were included. The most frequent horizontal locations of MF were found to be: between the two lower premolars (50%), and in line with lower second premolar (40%). The average long diameter of MF was 3.08 mm, SD = 0.65 mm in males (n = 50, range = 1.5-4.8 mm) and 2.46 mm, SD = 0.58 mm in females (n = 89, range = 1.2-4.0 mm), and the difference was statistically significant. Very weak positive correlation was found between age and MF diameter in females (r = 0.161) and the correlation was approaching statistical significance (p-value = 0.066), while a weak negative correlation was found between these two variables in males (r = -0.276) and the correlation was statistically significant (p-value = 0.038). It could be inferred from the results of the present study that about 95% success rate for mental nerve block anesthesia is expected when the anesthetic solution is administered between the two premolars; however this needs to be tested experimentally. It appears that there is a tendency for an increase in MF size with age in females as opposed to a tendency for size reduction with age in males; this might suggest a role for sexual hormones in influencing MF size.

Age prediction in the adult based on the pulp-to-tooth ratio in lower third molars: a cone-beam CT study / Predicción de edad en el adulto basada en la proporción pulpa-a-diente en terceros molares inferiores: un estudio por TC de haz de cono

Estimation of age-at-death is an integral part of the identification process of individuals in many forensic odontology cases where their identity cannot be determined by visualization or other ways. Dental age estimation in the adult is more challenging as most of the dentition is completely developed by 18 years of age. This study employs a mesio-distal (MD) pulp-to-tooth ratio taken at the neck of lower third molars (LM3) to provide an estimation of age at the time of radiographic imaging based on the well-known fact that pulp volume tends to decrease with advancing age due to continued apposition of secondary dentine throughout adulthood. A total of 155 Cone-beam computed tomography (CBCT) radiographs of LM3s for a random sample of 155 Jordanian Arabs (80 females, 75 males; age range= 18-58 years, mean age= 28.2 years, SD =10.0 years) were used. Both pulp and tooth MD diameters were measured at the neck. MD pulp-to-tooth ratios for LM3s were linearly regressed against age. Statistically significant negative association was found between an individual's age at the time of imaging and the MD pulp-to-tooth ratio taken at the neck. Specifically, the strength of the association is r= -0.361, which means only 13.0 % of the variation in age can be explained by the MD pulp-to-tooth ratio taken at the neck. Therefore, it was concluded that MD pulp-to-tooth ratio taken at the neck of LM3s is not a reliable predictor of chronological age in adults, possibly due to the large variation in the timing of LM3 development.

La estimación de la edad es una parte integral del proceso de identificación de los individuos, en muchos casos en odontología forense donde la identidad no puede ser determinada por visualización u otras formas. La estimación de la edad dental en el adulto es aún más difícil ya que la mayor parte de la dentición se desarrolla completamente a los 18 años de edad. Este estudio emplea una relación mesio-distal (MD) de pulpa a diente tomada a nivel del cuello de los terceros molares inferiores (LM3) para proporcionar una estimación de la edad en el momento de la imagen radiográfica basada en que el volumen de pulpa tiende a disminuir con el avance de la edad debido a la continua posición de la dentina secundaria a lo largo de la edad adulta. Se examinaron un total de 155 radiografías de LM3 en una muestra aleatoria de 155 árabes jordanos (80 mujeres, 75 varones), rango de edad = 18-58 años, edad media = 28,2 años, DE = 10,0 años. Específicamente, la fuerza de la asociación es r=0,361, lo que significa que sólo el 13,0 % de la variación en la edad puede explicarse por la proporción pulpa-a-diente.

Phase down of amalgam. Awareness of Minamata convention among Jordanian dentists.

OBJECTIVES: To assess the knowledge of Jordanian dentists toward phase down of dental amalgam as recommended by the Minamata Convention, and their training and competency in placing posterior composites.  Methods: This study was conducted through structured questionnaire interviews with randomly selected cohort of dentists in Jordan between March 2015 and June 2015. Out of 230 dentists who were invited, 196 (85.2%) agreed to participate. Dentists were asked if they know about the Minamata Convention. They were also asked about their training in placement of posterior composite.  Results: Out of the 196 interviewed, only 13.8% know about Minamata Convention and 17% had an undergraduate training in favor of placing composites in posterior teeth. Approximately 50% of those dentists were not trained in using rubber dam when placing posterior composites, while only 38.3% had training in sectional matrix placement. Undergraduate training did not influence (p=0.00) the dentists' decision to remove old amalgam based on patient's demands. Only 28.1% were of the opinion of discontinuing the use of amalgam due to its alleged health and environmental hazards. There was no general agreement on the type of composite, liner, and bonding strategy when placing posterior composites. Conclusion: Dentists are not well informed on the Minamata Convention and the phase down of amalgam. Training in posterior composite placement should be given more room in undergraduate curriculum and continuous dental education.

Satisfaction of undergraduate students at University of Jordan after root canal treatment of posterior teeth using rotary or hand preparation.

The aim of this study was to report the satisfaction of fifth year undergraduate students on the clinical use of rotary endodontic preparation compared with stainless steel standard technique and to evaluate the impact of rotary nickel-titanium instruments on undergraduate teaching. This study was carried out by the fifth year undergraduate students attending peer review sessions as a part of their training program using a questionnaire to assess their satisfaction with these two techniques. The overall results indicated a statistically significant satisfaction of the undergraduate students with the use of the nickel-titanium system (P < 0.001) compared to stainless steel standard technique. Under the conditions of this study, the results showed a positive acceptance and consensus among novice dental students regarding the use of ProTaper rotary files and the need for undergraduate teaching of rotary nickel-titanium systems in Jordan.

Technical quality of root canal treatment of posterior teeth after rotary or hand preparation by fifth year undergraduate students, The University of Jordan.

The aim of this study was to investigate the technical quality of root canal treatment provided by the undergraduate students as their first experience in molar endodontics using nickel-titanium (NiTi) files in a crown-down approach compared with stainless steel standard technique. This study was carried out by the fifth year undergraduate students attending peer review sessions as a part of their training programme, using two different questionnaires to assess the overall technical quality and potential problems regarding endodontic complications after root canal preparation with these two techniques. The overall results indicated a statistically significant difference in the performance of the two instrument techniques in difficult cases showing better performance of the NiTi system and mean rotary preparation time (P < 0.001). Under the conditions of this study, novice dental students, using NiTi ProTaper rotary files, were able to prepare root canals faster with more preparation accuracy compared with canals of same teeth prepared with hand instruments.

Hypodontia: prevalence and pattern amongst the living Druze population - a Near Eastern genetic isolate.

The Druze population is a small-sized Near Eastern genetic isolate with high rates of consanguineous marriages. The present study aimed at investigating prevalence, pattern and distribution of hypodontia in the permanent dentition, excluding wisdom teeth, amongst this population. Panoramic radiographs, dental casts, and anamnestic records of 85 un-admixed Druze schoolchildren (45 males, 40 females; age range=14-18 years, mean age=16 years, SD=0.5 years) were examined for evidence of hypodontia. Those with any type of facial clefts or craniofacial syndromes were excluded. Hypodontia prevalence was 11.8% (11.1% for males, 12.5% for females) with no statistically significant difference between sexes. The average number of missing teeth per child was 1.4 (1.2 for males, 1.6 for females). The majority (90%) of affected individuals exhibited minor hypodontia (one or two teeth missing). The most commonly missing teeth were upper lateral incisors and canines, followed by lower and upper second premolars. Asymmetrical hypodontia was more prevalent. Maxillary, left side, and anterior segment predominance were observed. The distinct features of hypodontia among the Druze population are the relatively high prevalence of minor hypodontia, and the upper lateral incisors and canines being the most commonly missing teeth.

Shear bond strength of self-adhesive resin cements to base metal alloy.

STATEMENT OF PROBLEM: Many self-adhesive cements have been introduced in the past few years, with little or no data regarding their clinical performance. This study investigated the shear bond strength of some recently introduced self-adhesive resin cements. PURPOSE: The purpose of this study was to evaluate the shear bond strength of self-adhesive and conventional resin-based cements to a base metal alloy. MATERIAL AND METHODS: Four groups (10-12 each) that comprised 3 self-adhesive cements (SmartCem2; RelyX Unicem; seT SDI) and a conventional resin-based cement (RelyX ARC) were tested. Cylindrical cement specimens (diameter, 3 mm; height, 3 mm) were applied to nickel-free base metal alloy (Sheradent) disks with a diameter of 12 mm, and the surface was treated with airborne-particle abrasion of 50 µm aluminum oxide. The metal disks were fixed in brass molds specifically designed for the shear bond test device. Test specimens were incubated at 37°C for 24 hours and then the shear bond was tested with a Zwick Roll testing machine at a 0.8 mm/min cross-head speed. In addition, bond failures were investigated and categorized as adhesive, cohesive, or mixed. Shear bond strengths were calculated by dividing the maximum debonding force over the cross-sectional area of each specimen. One-way ANOVA and the Tukey (honestly significant difference) post hoc test were used to test statistical significant differences among the groups (α=.05). RESULTS: Statistical analysis showed significant differences among different resin cements (F=14.34, P<.001). The highest mean shear bond strength was observed for SmartCem2 (14.18 MPa), and the lowest was reported for seT (3.52 MPa). The observed failure mode in all the materials was adhesive in nature, which occurred at the resin-metal interface. CONCLUSIONS: The early bond strength of self-adhesive resin cements varied significantly among the tested materials. SmartCem2 showed the highest bond strength, which was 4 times the strength observed for seT SDI.

Multiple lingual cusps trait on mandibular premolars and hypoconulid reduction trait on mandibular first molar in living Jordanian population. Intra- and inter-trait interactions.

The objective was to determine the expression and fluctuating asymmetry of two dental morphological traits in the living Jordanians: The lingual cusp number on the lower premolars (LP1 and LP2) and the hypoconulid (distal cusp) reduction on the lower first molar (LM1). In addition, both intra- trait and inter- trait interactions were analyzed. Three hundred school children (15.5 +/- 0.4 years) were involved. Impressions for the mandibular dental arches were taken, and dental casts were reproduced. The above-mentioned traits were observed. Paired sample t test and nonparametric correlation analysis were used for data analysis. Three-cusped LP1 was found in 11.40 % of the examined students, while the two-cusped LP1 was found in 88.60%. In comparison, the Three-cusped LP2 was found in 61.40% while the two-cusped LP2 was found in 38.60% of the observed subjects. The frequencies of the 4-cusped and 5-cusped LM1 were found to be 8.65% and 91.35%, respectively. Nonparametric correlation analysis revealed positive and statistically significant association between the expression of two lingual cusps on LP1 and on LP2 in both genders (p < 0.01), while there was no significant correlation between expression of two lingual cusps on either LP1 or LP2 and the hypoconulid loss on LM1 in both genders (p > 0.05). Bilateralism was highly significant in the tested traits in both genders (p < 0.001). This finding might be a sign of relatively low environmental stresses experienced by the living Jordanians and/or great ability of its individuals to buffer the adverse effects of such stresses on dental development. This study is a useful addition to the existing literature in that it examines a previously poorly characterized population and assists in placing the contemporary Jordanian population within the current framework of human population groups globally.

Marginal bone levels and soft tissue conditions around single-tooth implants with a scalloped neck design: results of a prospective 3-year study.

PURPOSE: Scalloped implants were developed to better maintain marginal bone. Therefore, this study evaluated marginal bone levels (MBLs) and soft tissue around single implants with scalloped necks in the esthetic zone prospectively over a 3-year period. MBLs were compared to those of conventional flat-platform implants at 1 and 3 years. MATERIALS AND METHODS: Patients received anterior single-tooth implants and were divided into two groups; the test group included implants with a scalloped neck design and the control group included conventional rough-surface implants with external hex. MBLs were compared radiographically at 1 and 3 years after crown insertion. For the test group, soft and hard tissue assessments were made at six different time points, beginning at abutment connection. Mesial and distal interproximal papillae and probing depths were assessed clinically. Data were analyzed with the Student t test and repeated measures analysis of variance on ranks (P < .05). RESULTS: Twenty-four patients (17 men, 7 women) took part; each group included 12 implants. The test group had significantly more marginal bone resorption than the control group at each time point (P < .001). With respect to changes in MBL values over time, a significant difference was detected between groups mesially (P < .001) but not distally. Statistical analyses demonstrated obvious significant increases with time (P < .001) in bone resorption and mesial papilla index. A significant increase over time in probing depths was demonstrated distally (P = .003) but not mesially. CONCLUSIONS: The scalloped implant did not stabilize interproximal bone remodeling and caused more bone loss than conventional implants. Soft tissue levels were not maintained around the scalloped implants.

Two implant/abutment joint designs: a comparative finite element analysis.

PURPOSE: The aim of this study was to compare the influence of abutment screw preload on the marginal bone stress around a conventional external-hex implant system and one with a new implant/abutment joint design. MATERIALS AND METHODS: Two implant/bone models, each consisting of three parts and fabricated of titanium and bone (cortical), were built and arranged with computer-aided design software. The first model represented an external-hex implant system, while the second had a tapered extension over the external hex, 1.5 mm high, so that the apical extension of the abutment screw in the assembly did not go beyond the lower level of the implant shoulder. Meshing and generation of boundary conditions, loads, and interactions were performed for the two models. All parts were meshed independent of each other. The sole load applied on the model was a torque of 32 Ncm on the abutment screw about its axis of rotation. RESULTS: The first model showed deformation of the implant collar, and the resulting von Mises stress was 60 MPa in the marginal bone. In contrast, no deformation was observed in the second model. CONCLUSIONS: The new implant/abutment joint eliminated the deformation at the implant collar area caused by the application of tightening torque and thus eliminated the resulting stresses in the marginal bone.

The effect of globin scaffold on osteoblast adhesion and phenotype expression in vitro.

PURPOSE: Different synthetic and natural biomaterials have been used in bone tissue regeneration. However, several limitations are associated with the use of synthetic as well as allogenous or xenogenous natural materials. This study evaluated, in an in vitro model, the behavior of rat osteoblastic cells cultured on a human globin scaffold. MATERIALS AND METHODS: Rat osteoblastic cells were isolated from the calvaria of 21-day-old fetal Sprague-Dawley rats. They were then grown in the presence of globin. Real-time polymerase chain reaction (RT-PCR) was performed to study the expression of cyclin D1, integrin Β1, Msx2, Dlx5, Runx2, and osteocalcin on days 1, 5, and 9. Moreover, alkaline phosphatase activity was measured on days 1, 3, 5, and 7. Alizarin red staining was performed on day 9 to observe calcium deposition. RESULTS: Cells were able to adhere, proliferate, and differentiate on globin scaffolds. Moreover, RT-PCR showed that globin may stimulate some key genes of osteoblastic differentiation (Runx2, osteocalcin, Dlx5). Globin had an inhibitory effect on alkaline phosphatase activity. Calcium deposits were seen after 9 days of culture. CONCLUSIONS: These results indicate that purified human globin might be a suitable scaffold for bone tissue regeneration.

Trends in the pattern of facial fractures in different countries of the world / Tendencias en el patrón de fracturas faciales en diferentes países del mundo

The aim of the present study was to examine the changes in the pattern of maxillofacial fractures between developed and developing countries over two time periods; (1987-1999) and (2000-2007). A comprehensive search of the literature using PubMed was conducted for publications on maxillofacial injuries published during the last 20 years. Only 45 articles met the inclusion criteria and the full-texts of these articles were thoroughly examined. For each of the included studies, different parameters were recorded. Calculated "weighed" percentages of each parameter across the total number of all patients were performed. The mandible was the most frequently fractured facial bone (57 percent). In the total period, the mean age of patients with facial fractures was 24.4 years and the incidence of facial fractures was higher in males (81.3 percent) than in females. The male to female ratio of patients with facial fractures was greater in developing countries (5.1:1.0) than that in developed countries (3.7:1.0) in the total period. Road traffic accident-related injuries had significantly decreased in developed countries and increased in developing countries over the two periods. However, assault-related facial injuries had significantly increased in developed countries and decreased in developing countries over the two periods. The body of the mandible was the most common mandibular fracture site (27.2 percent). It was concluded that mandibular fractures are more common than middle third injuries of the facial skeleton. Most patients affected by facial fractures in different countries were young adult males.

El objetivo del estudio fue examinar los cambios en el patrón de las fracturas maxilofaciales entre los países desarrollados y en vías de desarrollo en dos períodos de tiempo (1987-1999) y (2000-2007). Una búsqueda exhaustiva de la literatura en PubMed se llevó a cabo entre las publicaciones de lesiones maxilofaciales publicados durante los últimos 20 años. Sólo 45 artículos cumplieron con los criterios de inclusión, y los textos completos de estos artículos fueron examinados a fondo. En cada uno de los estudios incluidos se registraron diferentes parámetros. Se calculó el porcentaje de "peso" de cada parámetro a través del número total de pacientes. La mandíbula fue el hueso facial más fracturado (57 por ciento). En todo el periodo evaluado, la media de edad de los pacientes con fracturas faciales fue de 24,4 años y la incidencia de las fracturas faciales fue mayor en hombres (81,3 por ciento) que en mujeres. La razón hombre-mujer de los pacientes con fracturas faciales fue mayor en los países en vías de desarrollo (5,1:1,0) que en los países desarrollados (3,7:1,0) en todo el período. Las lesiones relacionadas con accidentes de tránsito disminuyeron considerablemente en los países desarrollados, mientras que aumentó en los países en vías de desarrollo durante los dos períodos. Sin embargo, las lesiones faciales relacionadas con asaltos aumentaron considerablemente en los países desarrollados y disminuyó en los países en vías de desarrollo durante los dos períodos. El cuerpo de la mandíbula fue el sitio de fractura más común (27,2 por ciento). Se concluyó que las fracturas mandibulares son las lesiones más comunes en el tercio medio del esqueleto facial. La mayoría de los pacientes afectados por fracturas faciales en los diferentes países fueron hombres jóvenes.

Influence of abutment screw preload on stress distribution in marginal bone.

UNLABELLED: Changes in an implant assembly after abutment connection might possibly cause deformation in the implant/abutment joint and even in the marginal bone. PURPOSE: The aim of this study was to evaluate the influence of abutment screw preload through the implant collar on marginal bone stress without external load application. MATERIALS AND METHODS: Models of three implant parts made of titanium (implant, abutment, and abutment screw) and cortical bone were built and positioned with computer-aided design software. Meshing and generation of boundary conditions, loads, and interactions were performed. Each part was meshed independently. The sole load applied to the model was a torque of 32 Ncm on the abutment screw about its axis of rotation. RESULTS: The implant collar was deformed axially after the screw was tightened (3 µm). This deformation resulted in 60 MPa of stress in the marginal bone. Moreover, pressure on the marginal bone in a radial direction was observed. CONCLUSIONS: It can be concluded that, without any external load application, abutment screw preload exerts stresses on the implant collar and the marginal bone. These findings should help guide the development of new implant/abutment joint designs that exert less stress on the marginal bone.

Effects of local melatonin application on implant osseointegration.

PURPOSE: The aim of this study was to assess the effect of local melatonin administration on bone osseointegration around implants in rabbit tibiae. MATERIAL AND METHODS: Ten female, 6-month-old New Zealand rabbits were randomly divided into two groups: the experimental group, where five rabbits were treated with local application of melatonin (3 mg) to implant sites when placed into the rabbit tibia, and the control group, those who where without additive materials. Four weeks later, animals were sacrificed; tibiae were dissected from soft tissues and fixed in buffered formaldehyde, and then included in methacrylate. Histological sections were performed to be studied under light microscopy and analyzed morphometrically to evaluate the amount of bone to implant contact (BIC), trabecular area density, and cortical area density. One-way analysis of variance test was used for statistical evaluation. p < .05 was considered to be significant. RESULTS: Histological evaluation showed more trabecular reaction in the melatonin group. Morphometrical analysis showed a statistically significant increase in trabecular BIC in the melatonin group when compared with the control group (24.61% ± 2.87 vs 13.62% ± 1.44; p < .01). Cortical BIC was decreased in the melatonin group, without statistical significance (71.08 ± 3.63 vs 76.28 ± 2.57; p = 0.31). Trabecular area density was increased significantly in the melatonin group (8.68 ± 1.61 vs 4.02 ± 0.36; p < .05). Cortical area density was decreased significantly in the melatonin group (91.31 ± 1.6 vs 95.7 ± 0.5; p < .05). CONCLUSION: Within the limitation of this animal study, local melatonin application at the time of implant placement might induce more trabecular bone at implant contact and higher trabecular area density.

Validation of an osteoporotic animal model for dental implant analyses: an in vivo densitometric study in rabbits.

PURPOSE: The achievement of primary stability in porous and soft bone, where implants are more likely to fail, is one of the unresolved challenges of implant dentistry. Therefore, the aim of the study was to validate an osteoporotic animal model for analysis of poor-quality bone. MATERIALS AND METHODS: Sixteen female New Zealand rabbits, each 6 months old and weighing 4 to 5 kg, were used in this study. The animals were anesthetized, and an in vivo densitometric analysis was performed by dual-energy x-ray absorptiometry (DEXA) to measure bone mineral density (BMD) in the calvaria, cervical spine, and tibia. Ovariectomy was then performed, and animals were fed a low-calcium diet that featured 0.07% calcium, rather than the 0.45% calcium of a standard diet, for 6 weeks. After this period, new densitometric measurements were carried out. Two-way analysis of variance was used for statistical evaluation. A P value of less than .05 was considered to be significant. RESULTS: Together, ovariectomy and a low-calcium diet were able to induce a quick decrease in BMD, as measured at 6 weeks by DEXA. This decrease was statistically significant in the calvaria (P < .001) and the cervical spine (P < .05) but not in the tibia. CONCLUSION: Based upon this study, ovariectomy and a low-calcium diet are able to induce experimental osteoporosis in rabbits in a short period of time.

Hypocone reduction and Carabelli's traits in contemporary Jordanians and the association between Carabelli's trait and the dimensions of the maxillary first permanent molar.

The objective of this study is to determine the prevalence of expression and bilateralism of two dental morphological traits in contemporary Jordanians: The hypocone reduction trait on the maxillary second permanent molar and Carabelli's trait on maxillary permanent first and second molars. Furthermore, inter-trait correlation and the relationship of Carabelli's traits with upper first molar dimensions were investigated. Three hundred subjects of school children at their 10th grade and of an average age of 15.5 +/- 0.4 years were involved. Alginate impressions for the maxillary arch were taken, dental casts were reproduced. The selected accurate casts were of 132 male- and 155 female-students. The frequencies of hypocone reduction trait on the maxillary second molar and Carabelli's trait on the maxillary molars were examined. Buccolingual and mesiodistal diameters of the maxillary first molar were measured and recorded. Paired Sample t test and Nonparametric Correlation analysis were used for data analysis. Hypocone reduction trait on the maxillary second molar was found in 29.8% of the examined students. Positive forms of Carabelli's trait on first and second molars were observed in 65.0% and 3.8%, respectively. Nonparametric correlation analysis revealed positive association between Carabelli's trait on first molar and hypocone reduction trait on the maxillary second molar. The presence of Carabelli's trait on first molar was strongly associated with the increase of buccolingual, but not the mesiodistal, diameter. Bilateralism was found highly significant in the tested traits and both genders (p < 0.001). This finding might be a sign of relatively low environmental stresses in the living Jordanian population and/or great ability of its individuals to buffer the adverse effects of such stresses.

Risk indicators of postoperative complications following surgical extraction of lower third molars.

OBJECTIVE: The aim of this prospective clinical trial was to evaluate the incidence of postoperative complications following surgical extraction of lower third molars (L8) and the risk factors and clinical variables associated with these complications. SUBJECTS AND METHODS: Three-hundred and twenty-seven consecutive patients (128 men and 199 women, mean age = 23.1 ± 3.9 years, range: 18-40) were recruited to this study. The L8 of all the patients were surgically extracted. Immediate and late complications like pain, swelling, trismus, paresthesia, bleeding, dry socket, infection and fracture were assessed 3 and 7-14 days, respectively, following the surgery. RESULTS: The most frequent immediate and late complications were slight pain, swelling, and trismus. Thirty-nine (11.9%) patients reported dry socket and 10 (0.3%) reversible sensory nerve complications. More immediate and late complications were experienced by females (p = 0.000 and 0.016, respectively). Older subjects reported more late complications. Frequent immediate and late complications were associated with preexisting pericoronitis, longer duration of operation, extraction of two molars, flaps with vertical incision, extractions with bone removal, extractions without tooth sectioning and distoangular impactions (p ≤ 0.05). Linear regression analysis showed that the above factors were able to predict postoperative complications. CONCLUSION: The most frequent immediate and late complications were slight pain, swelling, and trismus. Preoperative complaints, angulation of the impacted molars, duration of surgery, type of surgical flap, the need for bone removal and tooth sectioning could predict and had an impact on the incidence of postoperative complications following L8 removal. Females and older patients were likely to have more postoperative complications following surgical extraction of L8.