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.

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.

Local tolerance and efficiency of two prototype collagen matrices to increase the width of keratinized tissue.

AIM: to evaluate the local tolerance and efficiency of two experimental collagen matrices to increase the width of keratinized tissue. METHODS: in 12 pigs, two apically positioned flaps were prepared on both sides of the mandible. The denuded defect areas were randomly covered with one of two experimental porcine-derived collagen matrices (M1; M2). The other defect area was left untreated (control). At 1 and 6 months, clinical measurements for the width and thickness of the keratinized tissue were recorded. At 6 months, all animals were sacrificed. Descriptive and semi-quantitative histologic analyses were performed. For statistical analysis, the Kruskal-Wallis test and the Mac Nemar test were applied. RESULTS: the collagen matrices integrated well into the surrounding tissue without any signs of inflammation. The thickness and width of the keratinized tissue increased significantly over 6 months in all the groups, resulting in slightly more favourable results for M1 (compared with M2) with respect to the thickness and for M2 (compared with M1) with respect to the width of keratinized tissue. No statistically significant differences were observed for any of the evaluated clinical and histologic parameters among the three treatment modalities. CONCLUSIONS: within the limits of this animal study, the prototype collagen matrices can be used safely to increase the width of keratinized tissue.

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.

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.

Effect of combining platelet-rich plasma with anorganic bovine bone on vertical bone regeneration: early healing assessment in rabbit calvariae.

PURPOSE: The purpose of this study was to evaluate the combination of anorganic bovine bone allograft (ABB) with platelet-rich plasma (PRP) when used in vertical bone augmentation. MATERIALS AND METHODS: Sixteen healthy 6-month-old female New Zealand rabbits were used in this study. Rabbits were randomly divided into two groups of eight animals each. Created calvarial defects were grafted with ABB or PRP in the first group whereas, in the second group, one cylinder was filled with PRP+ABB and the contralateral cylinder was left ungrafted to be filled by autologous blood (control cylinder). Six weeks after intervention, animals were sacrificed and biopsies were taken. Densitometric, histologic, and histomorphometric analyses were performed to evaluate bone mineral density, vertical bone augmentation, and remaining graft volume, respectively. Statistical analyses were performed with the Mann-Whitney test, using a significance level of P < .05. RESULTS: Six weeks after rabbit calvariae were augmented, data analysis revealed that the mixture of PRP and ABB produced twice the vertical bone volume of ABB alone (P < .0001). CONCLUSION: Based upon this study of 16 rabbits, it appears that the combination of ABB with PRP resulted in increased vertical bone augmentation when compared with autologous blood in similarly sized created defects.

Narghile (water pipe) smoking among university students in Jordan: prevalence, pattern and beliefs.

BACKGROUND AND OBJECTIVES: Narghile is becoming the favorite form of tobacco use by youth globally. This problem has received more attention in recent years. The aim of this study was to investigate the prevalence and pattern of narghile use among students in three public Jordanian universities; to assess their beliefs about narghile's adverse health consequences; and to evaluate their awareness of oral health and oral hygiene. METHODS: The study was a cross-sectional survey of university students. A self-administered, anonymous questionnaire was distributed randomly to university students in three public Jordanian universities during December, 2008. The questionnaire was designed to ask specific questions that are related to smoking in general, and to narghile smoking in specific. There were also questions about oral health awareness and oral hygiene practices. RESULTS: 36.8% of the surveyed sample indicated they were smokers comprising 61.9% of the male students and 10.7% of the female students in the study sample. Cigarettes and narghile were the preferred smoking methods among male students (42%). On the other hand, female students preferred narghile only (53%). Parental smoking status but not their educational level was associated with the students smoking status. Smokers had also significantly poor dental attendance and poor oral hygiene habits. CONCLUSION: This study confirmed the spreading narghile epidemic among young people in Jordan like the neighboring countries of the Eastern Mediterranean region. Alarming signs were the poor oral health awareness among students particularly smokers.

An analysis of therapeutic, adult antibiotic prescriptions issued by dental practitioners in Jordan.

OBJECTIVE: The aim of this study was to determine the therapeutic adult antibiotics prescribed by dental practitioners working in the Jordan University Hospital. METHODS: Adult dental prescriptions for therapeutic antibiotics issued between 1 January 2003 and 31 May 2004 by dental specialists working in the Jordan University Hospital were included in this study. Data included the name of the antibiotic as well as the dose, quantity and presentation of the drug. Descriptive statistical analysis was carried out. RESULTS: Amoxycillin and metronidazole were the most commonly prescribed antibiotics, with 60% of the prescriptions containing amoxycillin and 39.4% containing metronidazole. 20.4% of the prescriptions were combination prescriptions containing metronidazole. In this study, long courses were observed for amoxycillin (60.5%), cephalosporins (21%) and metronidazole (59.7%). CONCLUSIONS: It seems that in the sample studied, Jordanian dental specialists have a tendency towards overprescribing antibiotics both in quantity and duration. This may constitute a problem particularly when considering the remaining sectors of less well-educated dental practitioners. The results will be used to increase awareness among dental practitioners in the field of antibiotic prescribing throughout the University of Jordan and the Jordanian Dental Association.

Multicenter retrospective study of cement-retained implant-supported anterior partial prostheses: success and restoration evaluation.

PURPOSE: The aim of this multicenter study was to evaluate implant success and restorative complications of cement-retained implant-supported anterior partial prostheses in Jordan. MATERIALS AND METHODS: A retrospective study of all implants with a minimum of 1-year follow-up were used to support fixed, cement-retained restorations from April 2000 until March 2007. The cement-retained implants were loaded with either single- or multiple-tooth replacements. The Fisher exact test was performed to test the presence of any statistically significant difference in success concerning gender or arch of placement. RESULTS: Eighty-seven implants were placed in the anterior region of the mandible or maxilla in 49 patients at multiple clinical practices in Jordan. The age of the patients ranged from 17 to 85 years. Eighteen implants were placed in the mandible and 69 in the maxilla. Three maxillary implants in 2 male patients had 3-mm horizontal bone loss. Those 3 implants are still functioning and were considered surviving implants but not successful implants. Therefore, the implant cumulative survival rate for both arches and genders was 100%. The implant cumulative success rate was 95.78%. Three crowns (maxillary) were dislodged. No significant differences were revealed regarding gender or arch of placement (P > .05). CONCLUSIONS: Cement-retained implants exhibited high survival and success rates among a Jordanian population.

Frequency estimates and risk factors for postoperative morbidity after third molar removal: a prospective cohort study.

PURPOSE: The aim of this study was to estimate the frequency of postoperative complications after mandibular third molar (M3) surgery and identify the risk indicators. PATIENTS AND METHODS: This was a prospective cohort study of a sample of subjects having at least 1 mandibular M3 surgically extracted at a teaching hospital in Jordan. The predictor variables were categorized as patient, anatomic, and operative specific. The outcome variables were postoperative complications recorded as present or absent. Bivariate analyses were computed, then a multivariate logistic regression model was used to identify independent predictors for the common postoperative complications. RESULTS: The study sample was comprised of 149 patients who had 245 extractions. The mean age was 21.6 +/- 3.32 years; 64.9% were females. In the multivariate logistic regression model, age (P = .033, odds ratio [OR] = 1.178), M3 side in relation to the handedness of the operator (P = .048, OR = 4.078), and lingual retraction (P = .001, OR = 11.293) were the variables found as independent predictors for alveolar osteitis. The level of impaction had a significant association with trismus, and operation time acted as an independent predictor for pain (P < .001, OR = 1.085). CONCLUSION: Postoperative morbidity increases with older age, deeper impaction, M3 side differing from the handedness of the operator, and longer procedures.

The effect of all-ceramic and porcelain-fused-to-metal restorations on marginal peri-implant soft tissue color: a randomized controlled clinical trial.

The aim of this study was to test the color-change effect of all-ceramic restorations compared with porcelain-fused-to-metal (PFM) restorations on marginal peri-implant soft tissue. Thirty patients were randomly divided into 2 groups of 15 subjects each. The all-ceramic group received all-ceramic crowns on aluminum oxide-based abutments, while the PFM group received crowns on titanium or gold abutments. A reflectance spectrophotometer was used to measure the color difference (deltaE(Implant)) between the midfacial peri-implant mucosa before and after restoration insertion. The color difference (deltaE(Tooth-implant)) between the midfacial peri-implant mucosa and the gingival margin of the corresponding neighboring tooth was tested. The mucosal thickness was measured midfacially around the implant (MT(Implant)) and neighboring tooth (MT(Tooth)). deltaE(Implant) values were similar for the all-ceramic (7.4 +/- 2.7) and PFM groups (7.6 +/- 2.8). The all-ceramic group induced significantly less visible mucosal color change (3.4 +/- 1.4) compared to the PFM group (5.2 +/- 2.3). The MT(Implant) value of the all-ceramic group was 3.4 +/- 0.8 mm, while that of the PFM group was 2.9 +/- 0.9 mm, which was not significantly different. Significant differences were found when comparing MT(Implant) (3.1 +/- 0.9) and MT(Tooth) (1.2 +/- 0.3) values for test and control groups. All-ceramic restorations revealed a better color match to the neighboring teeth than PFM restorations.

An in vitro evaluation of the antimicrobial activity of nine root canal sealers.

AIM: The purpose of this in vitro study was to analyze the antimicrobial activity of root canal sealers by using the agar diffusion test (ADT). METHODS AND MATERIALS: Three categories of root canal sealers were included in the study: resin-based sealers (4), zinc oxide-based sealers (3), and calcium hydroxide-based sealers (2). The microbial strains used were: S. aureus (2 strains), C. albicans (2 strains), and E. faecalis (1 strain). Statistical analysis was conducted using a one-way analysis of variance (ANOVA). Tests of differences were analyzed using the Tukey's test with a value of p < 0.05 considered statistically significant. RESULTS: The antimicrobial activity of root canal sealers was ranked in descending order as follows: Sealite Regular, Cortisemol, Dentalis KEZ, AH26, Sealapex, Acroseal/Topseal, and Endorez/AH plus. CONCLUSION: Root canal sealers showed different inhibitory effects depending on their types and the bacterial strains tested. Root canal sealers containing formaldehyde and eugenol proved to be effective against the microorganisms studied. CLINICAL SIGNIFICANCE: The incorporation of antimicrobial components into root canal sealers may become an essential factor in preventing the re-growth of residual bacteria and control of bacteria re-entry into the root canal system.

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.

Multicenter retrospective study of ITI implant-supported posterior partial prosthesis in Jordan.

PURPOSE: The aim of this multicenter study was to evaluate success and restorative problems of ITI (ITI Dental Implant System, Straumann AG, Basel, Switzerland) implant-supported posterior partial prostheses in Jordan. MATERIALS AND METHODS: One-hundred forty-one ITI implants were placed in the posterior region of the mandible or the maxilla in 66 patients at multiple clinical practices in Jordan. The age of the patients ranged from 17 to 85 years. The implants were retrospectively analyzed from the first date of placement in September 1999 until May 2006. Eighty-three implants (58.87%) were placed in the mandible, and 58 (41.13%) in the maxilla. The implants were loaded with either cement-retained single- or multiple-tooth replacements. RESULTS: Three maxillary implants of two male patients have been lost (2.13% of the total and 5.12% of the maxillary implants). Failed implants were of wide-neck type with 6-mm lengths. Moreover, in another two male patients, two single implants at the maxillary premolar region exhibited significant bone loss from the buccal side of the implant surface (2-mm bone resorption). Those two implants are still functioning and were included in calculating the survival rate but not the success rate. Therefore, the cumulative survival rate for both arches and genders was 97.87% and that for male patients in the maxillary region was 94.88%. The cumulative success rate for both arches and genders was 96.45% and that for the maxillary region was 86.21%. The corresponding rates concerning implants in female patients and the posterior mandible of both genders were 100% for both survival and success rates. Only one crown (mandibular) and another two abutment bridge (maxillary) were decemented in different patients (2.13%). CONCLUSIONS: The survival and success rates of implants placed in male patients and in the maxilla were lower than that of implants placed in female patients and in the mandible. Cement-retained restorations showed minimal complications.

Effect of dental implant cross-sectional design on cortical bone structure using finite element analysis.

PURPOSE: This finite element analysis investigation evaluated the effect of different implant cross-sectional designs on bone stress levels under different loading patterns. MATERIALS AND METHODS: Finite element analysis program was used to construct four different three-dimensional models describing 4x10-mm implants in blocks of cortical and trabecular bone. A 5-mm-long abutment was modeled above each implant. The implant in model 1 was unthreaded, while in model 2 the implant was circularly threaded. The third implant in model 3 had the cross-sectional shape as a 16-sided star-shaped design. The implant in model 4 was constructed unthreaded, with a diameter of 4.5 mm. Vertical and horizontal loads of 100 N each were applied on the top middle node of each implant assembly. All nodes at the bottom surface of the bone models were restrained. RESULTS: By comparing models 1, 2, and 3, the lowest bone stress values under vertical and horizontal forces were observed around the unthreaded implant in model 1 (8.92 and 94.52 MPa, respectively). The highest stress value under vertical loading was shown around the threaded implant in model 2 (10.07 MPa), whereas the highest stress value under horizontal loading was observed around the star-shaped implant in model 3 (108.40 MPa). Model 4, with a wider unthreaded design, had stress values under vertical and horizontal loading of 7.32 and 71.35 MPa, respectively. CONCLUSIONS: It was concluded that the unthreaded implant design produced the least bone stress. An increase in implant diameter could produce marked reduction in stress value in the bone around the neck of the implant.

The staggered installation of dental implants and its effect on bone stresses.

PURPOSE: The aim of this study was to investigate the effect of offsetting the middle or peripheral implant on the compressive stress values in the crestal bone around the neck of the dental implant. MATERIALS AND METHODS: Three finite element models describing three titanium implants installed in quadrilateral pieces of bone was executed. A 2-mm nickel chromium superstructure representing a bridge was modeled over the implant abutments. In model 1, implants were installed along a straight line. Model 2 had the middle implant installed outside the line connecting the two peripheral implants buccally. Model 3 had the mesial implant installed out of alignment. Six 100-N loads were modeled on top of the mesial and middle implants of the three models individually. Loads 1 and 2 were directed vertically on the mesial and middle implants, while loads 3 and 4 represented the horizontal loads in the buccal direction. Loads 5 and 6 were directed mesially on the mesial and central implants. Maximal compressive stress levels in the crestal bone of the three models were then investigated. RESULTS: The results demonstrated that offset implant installation revealed slightly lower bone stresses under buccally or lingually directed horizontal forces. Slightly higher bone stresses under vertical loads were observed. Horizontal mesial or distal loads resulted in slightly higher bone stresses than those caused by buccal or lingual loading. CONCLUSIONS: The in-line implant alignment clearly had the safest compressive stress outcome on the surrounding structure under vertical loads. Under buccolingual loads, implant alignment with peripheral offset would have, relatively, the safest compressive stress outcome on bone.

Canal configuration in the mesio-buccal root of maxillary first molar teeth of a Jordanian population.

The purpose of this study was to investigate the canal configuration in the mesio-buccal root of maxillary first molar teeth of a Jordanian population using a clearing technique. One hundred extracted maxillary first molars were collected from Jordanian patients. After a standard access preparation, canals were stained, decalcified, dehydrated, and then rendered clear. The prevalence of a second canal in the mesio-buccal root was 77.32%. Types IV and II canal systems were the most common types with prevalence of 35.05% and 27.83%, respectively. Additionally, 28.86% showed lateral canals mostly located in the apical third and 37.11% had intercanal communications, mainly in the middle third of the root. It was concluded that the prevalence of mesio-palatal canals was high and Types IV and II canal systems were the most prevalent.

Dental extraction for patients presenting at oral surgery student clinic.

The aim of this study was to examine the reasons for dental extraction and to determine the pattern of tooth loss in patients seeking care at the oral surgery teaching clinics in the Faculty of Dentistry of the University of Jordan, Amman, Jordan, over a 3-year period. Data pertaining to the dental extractions of 2435 patients were analyzed. The results showed that 63.8% of the teeth included in this study were extracted because of dental caries, 22.9% because of periodontal disease, and 11.0% for prosthetic reasons. Pericoronitis, orthodontic treatment, trauma, and eruption problems accounted for 2.4% of the reported extractions. The upper premolars were the teeth most commonly extracted, and the lower first and second molars were the teeth most commonly extracted because of dental caries. The logistic regression test revealed that extraction because of dental caries occurred mostly in the group aged 21 to 30 years (P < .001). Periodontal disease was not likely the cause of extraction in patients younger than 40 years. Mandibular incisors were the teeth least likely extracted because of dental caries (P < .001), but they were the teeth most commonly extracted because of periodontal disease (P < .001). Extraction for orthodontic reasons mostly involved the premolars (P < .05) and occurred in patients 20 years of age or younger (P < .001). Men were less likely to lose teeth because of caries and periodontal disease (P < .05 and P < .001, respectively) and were more likely to lose teeth for prosthetic reasons and trauma. The information gained from this study is useful to shift oral health planning toward emphasizing the importance of maintaining natural dentition and preventing dental disease.