Effect of Temporary Cement, Surface Pretreatment and Tooth Area on the Bond Strength of Adhesively Cemented Ceramic Overlays-An In Vitro Study.

Several viewpoints have been reported regarding the effect of temporary cements, different surface pretreatment protocols before adhesive cementation, and predictive factors. This in vitro study tested if temporary cement, pretreatment of the tooth surface, the size of enamel or dentine influence adhesive cementation to zirconia ceramics. Twenty premolars were prepared for determination of enamel and dentin area, bond strength test and failure analysis. The samples were divided into two groups: untreated prior adhesive cementation (n = 10) and with temporary cementation done, pretreated prior adhesive cementation (n = 10). Zirconia overlays (Katana Zirconia STML) were cemented on the grounded flat teeth surfaces using Panavia V5. An additional six premolars underwent dentine tubule analysis with SEM to detect temporary cement residues after temporary cementation on an untreated tooth surface (n = 3) and on a pretreated surface (n = 3). The independent sample t-test was used to compare the two groups and the means of the total tooth, dentin or enamel areas did not differ significantly between the untreated and pretreated specimens. The mean tensile bond strength was significantly (p = 0.005) higher in the pretreated specimens (337N) than in the untreated ones (204N). The overall multivariable linear regression model with three predictors (surface pre-treatment, enamel area and dentine area) was significant (p = 0.003), among which the size of enamel was the strongest predictor (ß = 0.506; p = 0.049), followed by the pretreatment effect (ß = 0.478; p = 0.001) and the size of dentin area (ß = -0.105; p = 0.022).

Resin Cement Residue Removal Techniques: In Vitro Analysis of Marginal Defects and Discoloration Intensity Using Micro-CT and Stereomicroscopy.

The objective was to compare marginal defects and evaluate discoloration for adhesively cemented veneers in vitro when using two cement removal techniques. Twenty premolars were prepared with chamfer and borders in enamel. IPS e.max CAD veneers were cemented using Panavia V5 and divided in two groups (n = 10): cement excess removed with a probe after tack-curing for 3-5 s, or cement excess removed with a brush, then completely polymerized. All teeth were stored in alginate gel until micro-CT examination. Scanning was performed twice: directly after cementation and after thermocycling (5000 cycles, between 5 and 55 °C). To analyze discoloration, teeth were colored using 0.5% basic fuchsine and examined under a stereomicroscope. Depth of dye infiltration was scored 0 (no discoloration) to 5 (discoloration along the entire margin). Statistically significant differences of cement defects before thermocycling were reported, where brushing showed more defects than probing (p = 0.0161). After thermocycling, the defects increased for both groups. Extensive discoloration was the most common (55.56%) when removing excess by probing; by brushing, 90% of the specimens exhibited slight discoloration (p = 0.008). Regression analysis showed no relationship between type of defect and degree of discoloration. Removing cement with a brush causes more marginal defects, however less discoloration after thermocycling.

Edentulous Patient Satisfaction with Conventional Complete Dentures.

Background and Objectives: Edentulism is considered to be an impediment impacting both patients' quality of life and their nutrition. Conventional complete dentures are still a preferred treatment. However, there is no consensus on the most important factors which could substantially reduce the risk of patient dissatisfaction. This study evaluated the following determinants concerning patient satisfaction with complete maxillary and mandibular dentures: sex, denture-related functional and aesthetic aspects, and the degree of bone resorption. Materials and Methods: This study included 70 patients aged 34-81 years of age. All complete dentures were made by following the same technology. Visual analogue scales were used to assess patients' overall satisfaction with dentures, comfort, ability to speak and chew, denture aesthetics, stability, and ease of prosthesis cleaning. Satisfaction with upper and lower dentures was rated separately. The degree of bone resorption was classified by using the Kalk and de Baat (1989) method. Results: The mean (SD) age of the study participants was 67.3 (10.4) years; 65.7% (n = 46) were females and 34.3% (n = 24) were males. There were no significant sex-based differences in resorption of the maxilla or mandibula. There were significant differences between maxillary and mandibular dentures, with lower mean satisfaction scores concerning chewing and maxillary complete dentures, and in regard to stability and comfort for mandibular complete dentures. There was a non-significant overall lower satisfaction with increased age. In multivariate analysis for mandibular complete dentures, aesthetics and stability significantly predicted the patient's comfort levels, and the patient's comfort significantly predicted overall satisfaction. For maxillary complete dentures, patient comfort and aesthetics significantly predicted overall patient satisfaction. Conclusions: Age, sex, and degree of resorption were not associated with patient satisfaction with complete dentures. Overall, patient satisfaction with both maxillary and mandibular complete dentures was related to their comfort level and denture aesthetics, and patient comfort itself was associated with stability of the mandibular denture.

Gray values of the cervical vertebrae detected by cone beam computed tomography for the identification of osteoporosis and osteopenia in postmenopausal women.

OBJECTIVES: This study aimed to determine whether the gray values (GVs) of the second and third cervical vertebrae in cone beam computed tomography (CBCT) are affected by general bone mineral density (BMD) in postmenopausal women and to evaluate whether CBCT can be used for predicting the risk of osteoporosis. STUDY DESIGN: The present cross-sectional study included 127 edentulous postmenopausal women (average age, 70.4 ± 8.9 years) who underwent CBCT examinations. BMD measurements of the lumbar spine and both femoral necks were performed by dual-energy x-ray absorptiometry. The CBCT images were analyzed with OnDemand3D Dental software. GVs of the axial and sagittal sections of the cervical second and third vertebral bodies were obtained. RESULTS: The GVs of the second and third cervical vertebrae decreased significantly with decreasing BMD. The axial GV of the second cervical vertebra showed the highest sensitivity (80.6%), highest negative predictive value (89.0%), lowest negative likelihood ratio (0.39), and highest area under the curve value (0.68) to predict osteoporosis. CONCLUSIONS: Women with reduced BMD have lower GVs for the second and third cervical vertebrae. Changes in the GV of the second vertebra can potentially be used to determine the risk of osteoporosis in postmenopausal women.

Bone mineral density and mandibular residual ridge resorption.

PURPOSE: This prospective, cross-sectional study evaluated the relationship between bone mineral density (BMD) and the width and height parameters of the mandibular residual ridge. MATERIALS AND METHODS: BMD was determined in the lumbar spine and femoral necks by dual energy x-ray absorptiometry (DXA) in 45 edentulous, postmenopausal women (mean age, 72.08 ± 8.53 years) who had used conventional complete dentures for at least 3 years. Measurements of the mandibular residual ridge were performed using cone beam computed tomography (CBCT). Height and width measurements were performed in the midline and adjacent to the mental foramina. Data were analyzed with descriptive and analytic statistics. The relationship between BMD and mandibular height and width measurements was assessed using analysis of variance as well as linear and multivariate regression analyses. Eight patients were excluded from the study because they did not complete both of the required imaging analyses (DXA and/or CBCT). RESULTS: There was no statistically significant relationship between BMD and mandibular bone height measurements in the midline and both regions of the mental foramina, and no statistically significant relationship existed between BMD and mandibular bone width measurements in the midline and both of the mental foramina regions. CONCLUSIONS: Postmenopausal women with reduced general BMD do not appear to have a reduction in the size of the mandibular residual ridge.

Vitamin D status and its seasonal variations and association with parathyroid hormone concentration in healthy women in Riga.

UNLABELLED: The aim of the study was to describe the vitamin D status and its seasonal variations in women living in Riga, Latvia, to examine an association between the concentrations of plasma 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH), and to determine the threshold for plasma 25(OH)D above which there is no further suppression of PTH. MATERIAL AND METHODS: The data of 189 healthy Caucasian women were analyzed. The serum levels of 25(OH)D, PTH, and phosphorus were measured twice a year. All the participants were divided into 3 groups according to vitamin D supplementation and the reproductive status. RESULTS: The overall mean level of 25(OH)D was 32.8 ng/mL with significantly lower levels being in winter when compared with those in summer (28.2 ng/mL vs. 37.5 ng/mL, respectively; P<0.05). PTH was negatively associated with 25(OH)D. A threshold level of plasma 25(OH)D above which no further suppression of PTH occurred was found to be 38 ng/mL. Postmenopausal women not taking vitamin D supplements and without exposure to sunlight had 25(OH)D deficiency in winter and summer (92% and 88%, respectively). The most significant seasonal fluctuations were seen in the women of the reproductive age not taking vitamin D supplements and without exposure to sunlight, of which 47% had 25(OH)D deficiency in summer and 69% in winter. CONCLUSIONS: An optimal concentration of 25(OH)D was found to be 38 ng/mL. According to this definition, 70.4% of all the healthy women were classified as vitamin D deficient in winter and 59.8% in summer. The highest proportion of vitamin D deficient individuals was found in the group representing the postmenopausal women not taking vitamin D supplements.

Postmenopausal osteoporosis and tooth loss.

OBJECTIVE: The aim of this study was to determine relation between tooth loss and general body bone mineral density in postmenopausal female who were seeking for prosthetic treatment. MATERIAL AND METHODS: There were included 79 women in this study (age from 49-81 years, mean age 62.9 years) with partial tooth loss. For all patients bone mineral density measurements for lumbar spine and both femoral necks by dual energy X-ray absorptiometry (Lunar DEXA DPX-NT, GE Medical Systems) were performed. Based on DEXA results patients were divided into 3 groups: normal bone density (T-score ≥-1.0), osteopenia (T-score from -1.0 till -2.5) and osteoporosis (T-score ≤-2.5). Dental investigation was performed to detect existing teeth. ANOVA analysis of variance was used to determine relationship between different variables by group. To test correlation between different values Pearson correlation was used. RESULTS: The number of teeth in different bone mineral density groups is almost similar. There are no statistically significant differences between groups according the number of the all teeth present and according the number of teeth in maxilla and mandible. There is no significant correlation between the number of the teeth and DEXA readings, except there is weak correlation between the number of maxillary posterior teeth and bone mineral density in femoral neck. CONCLUSION: There is no correlation between number of the teeth and general bone mineral density.

The influence of bone mineral density and body mass index on resorption of edentulous jaws.

OBJECTIVE: The aim of this study is to determine the relation of osteoporosis and body mass index to edentulous jaw bone resorption. MATERIAL AND METHODS: Study included 48 postmenopausal totally edentulous female patients, aged 50 to 84 years (average age 69.73), with period of at least 2 years after last tooth extraction. Bone mineral density was determined in the femoral neck and the lumbar area L2-L4 by dual energy x-ray absorptiometry (DEXA) using Lunar DEXA DPX-NT, GE Medical Systems hardware. Body mass index was calculated (BMI (kg/m(2))) using data from DEXA results. Lateral cephalogram (Pantomograph Trophycan C), and radiological measurement in the symphysis of the mandible was performed for each patient. Degree of the edentulous residual ridge resorption was determined clinically on diagnostic casts of anatomic impressions by classification of Kalk. RESULTS: There is no statistically significant difference between groups, comparing mandibular bone height changes (p=0.054) and various degrees of residual ridge resorption in maxilla (p=0.743) and mandible (p=0.752) with different bone mineral contents. There is a statistically significant correlation between radiological mandibular measurement and body mass index (p=0.004). Statistically significant difference is also observed between various degrees of residual ridge resorption in maxilla (p=0.049) and mandible (p=0.027) and body mass index. CONCLUSIONS: Resorption of edentulous jaw bone does not increase when bone mineral density decreases. More severe manifestation of edentulous jaw bone resorption is observed in patients with diminished body mass index.

Changes in the periodontal condition after replacement of swaged crowns by metal.

Evidence based clinical studies have shown exact recommended design for artificial crown reconstruction with acceptable long-term results taking into an account the biological price. Previous histological and clinical studies proved that fixed prostheses might influence the periodontal condition of crowned teeth, if not all biological criteria have been considered. The aim of the present study was to assess the periodontal condition of the crowned teeth after stainless steel swaged crowns were replaced by cast metal ceramic crowns. Participants were selected at the Institute of Stomatology, Stradin's University. Selection criteria included need to replace existing swaged crowns by metal ceramic crowns for patients with absence of any systemic disease. Following symptoms of periodontal condition were examined - presence of inflammation (clinical signs, probing) and pocket depth. Assessments were carried out at four different points of time (first appointment after replacement existing swaged crowns by temporary crowns; two weeks after cementation of permanent metal ceramic restoration; after three month; after six month). Overall bleeding score "2" and "3" at the first measurement was observed in majority of study population. Bleeding scores between the 1st and the 4th measurement was significantly lower (p<0.01). The same trend was observed also in the reduction of pocket depth. Overall mean value of pocket depth gradually decreased from the 1st till the 4th measurement. Replacement of swaged crowns by metal ceramic improves gingival health and leads to better long-term prognosis for restored teeth. It is recommended that swaged crowns be replaced with more biologically friendly crowns.

Construction faults associated with complete denture wearers' complaints.

Edentulism is considered a poor health outcome and may compromise the quality of life. Although the number of adults losing their natural teeth is diminishing, there are still large numbers of edentulous adults in the population. A retrospective study was conducted with information derived from literature (from 1984 till 2004) about the patients who experienced ongoing difficulties with new complete dentures, to determine possible underlying causes. Relationships were observed when denture construction or design faults were compared with patient complaints and the advised solution of the problem. CONCLUSION. This study suggests that in most instances, complete denture patients present with complaints only when there is real design fault. Clinician must carefully evaluate the denture for faults in denture base extension and horizontal and vertical jaw relationships.

The effect of 2 different diameter cast posts on tooth root fracture resistance in vitro.

Prosthetic treatment frequently involves the restoration of endodontically treated teeth (ETT), which in turn implies that there has been a reduction of the crown due to previous restorative treatment, trauma and/or endodontic manipulations. The prognosis of a restored ETT is very much dependent on pre-endodontic status of the tooth, the quality of the endodontic treatment, the amount remaining tooth structure and the bone support. The aim of this study is to measure fracture resistance of extracted premolar teeth restored with 2 different diameter posts. Extracted premolars were collected and stored in physiologic solution at 5 degrees C. The teeth were examined for fractures by direct and transillumination observation and 40 premolars were accepted for the study. The PC were modelled using the appropriate diameter plastic pattern for the post and Pattern Resin (GC) was used to model the core part of the PC. The PC patterns were invested and cast in cobalt chromium alloy and then cemented using zinc phosphate cement. Fracture resistances of the samples were tested in an "Instron 4301" (Instron Series IX Automated Material Testing System Version 5) with a loading speed of 0.5 mm/min. The data for each sample was recorded graphically. Both groups were analyzed using the t-test (p<0.01) in relationship to the mean value of that group. Post and cores significantly reduce the fracture resistance of the tooth and should be used only to secure retention and resistance form for full coverage crowns. Teeth with a larger diameter post have a reduced fracture resistance than teeth with a smaller diameter.

Jaw tracking devices--historical review of methods development. Part I.

Chewing or mastication is one of the main functions of the stomatognathic system. The use of devices for quantitatively measuring mandibular motion has recently become more common in scientific and clinical use. Often, the goal has been to provide an objective basis for diagnosing musculoskeletal disorders of the jaws, to monitor the progress of active treatment methods or to evaluate prosthodontic treatment functional results. To better understand differences between various systems to record mandibular motion a review of recording methods presented over the years was made. To give fundamental description for development of existing methods review was divided in three parts. Part I includes analyses of methods using mechanical devices, photographic methods and roentgenographic methods, describing not only technologies by themselves, but also analyzing essential limitations, possible direction of the functional improvement and, specially, their scientific and clinical significance.

The masticatory system--an overview.

Masticatory muscle physiology has been evaluated mostly from electromyographic recordings. However, electromyography coupled with jaw-tracking devices has provided much more information of the correlation between jaw movements and muscle activity. Knowledge of how the mandible moves during mastication has greatly influenced procedures in clinical dentistry. The aim of this overview is to give basic description of the classical studies of the physiology, function and neural control principles of the mastication. Mastication is the action of breaking down of food, preparatory to deglutition. This breaking-down action is highly organized complex of neuromuscular and digestive activities. The duration and forces developed in the power stroke vary within and between individuals and for the type of the food being chewed. It has been suggested that the observation of masticatory movements may be of diagnostic value for assessing disorders of the stomatognathic system, but there is not clear evidence to show significant differences. The action of masticatory muscles during chewing varies between subjects in amplitude, onset timing, and duration of the chewing cycle. Since tooth guidance has an enormous influence on muscle activity during chewing and swallowing, it is advisable to make restorations compatible with the functional movement patterns of the patient rather than expect the patterns of the mastication to adapt to the new made restorations.

Jaw tracking devices--historical review of methods development. Part II.

Chewing or mastication is one of the main functions of the stomatognathic system. The use of devices for quantitatively measuring mandibular motion has recently become more common in scientific and clinical use. Often, the goal has been to provide an objective basis for diagnosing musculoskeletal disorders of the jaws, to monitor the progress of active treatment methods or to evaluate prosthodontic treatment functional results. To better understand differences between various systems to record mandibular motion a review of recording methods presented over the years was made. To give fundamental description for development of existing methods review was divided in three parts. Part II includes analyses of electronic and telemetric methods, magnetometry and opto-electronic methods, describing not only technologies by themselves, but also analyzing essential limitations, possible direction of the functional improvement and, specially, their scientific and clinical significance.