Mandibular Bone Mineral Density Changes Dependet on the Denture Support. A Six Month Follow up Study

Reduction in the height of the alveolar edentulous ridge in denture wearers is a well documented problem which depends on various local and systemic factors. Changes of bone mineral density (BMD) in denture wearers have not yet been documented in follow-up studies. The aim of this study was to determine the changes in BMD of the mandible in complete (CD) and removable free-end saddle denture wearers (RPD) during a six month period (both groups had complete dentures in the maxilla). Twenty RPD patients (5 male, 15 female) and 20 CD wearers (7 male, 13 female) participated. The BMD measurements were performed on digitised dental panoramic radiographs (DPR) with a 5 step copper stepwedge attached to each film cassette. Grey levels of each step of the stepwedge were transformed to optical density values and using the 3rd degree polynomial the regression formula was calculated for each digitised image to express BMD values of the measured region of interest (ROI) in the copper stepwedge thickness equivalents. The results revealed that the BMD values of the examined ROIs under the distal end of the CD decreased, and in contrast, the matching BMD values under the distal end of the RPD increased, during the six month period, although the changes did not reach a statistically significant level (p>0.05). The BMD values on gonion increased significantly in both examined groups (p<0.05), which was attributed to the increased load of the strain forces of the masseter muscle at gonion after the denture delivery. Supported by the Ministry of Science and Technology, Republic of Croatia, Project No. 065911

ITI Implant-Supported Dentures: Assessment of Peri-Implant Bone Changes

Mandibular overdentures, supported by osseointegrated implants, is a well established, successful treatment of partialy edentulous patients. The aim of the study was to analyse the bone mineral density (BMD) in the implant site of the mandibles with ITI implant-supported overdentures when compared with the same site of the edentulous mandibles in complete denture wearers. Eight patients (4 males, 4 females) with 16 ITI implants and overdentures in the mandible and 8 complete denture wearers (4 males, 4 females) who had approximately the same body mass index and the same age participated. The BMD measurements were performed on digitised periapical radiographs with a 10 steps copper stepwedge attached to each film. Grey levels of each step of the stepwedge were transformed to optical density values and using the 3rd degree polynomial the regression formula was calculated for each film. The BMD values of each measured region of interest (ROI) were expressed in the copper stepwedge thickness equivalents. BMD values of the ROIs close to the implant were statistically compared to the same ROIs in the edentulous mandible using t test for independent samples. BMD values were significantly higher in ITI implant ROIs compared to the matching edentulous mandible sites (p<0.05). We concluded that an increased function after the implant-overdenture treatmentcaused a load-related bone formation which minimizes the physiologic age-related mandibular BMD loss. Supported by the Ministry of Science and Technology, Republic of Croatia, Project No. 065911

Alveolar Bone Loss on Abutment and Non-Abutment Teeth as Related to Removable Partial Denture Wearing. A Six Month Follow up Study

Loss of interdental alveolar bony septum can be determined directly from a radiograph as a percentage length of the interdental bony crest of the alveolus to the distance from cemento-enamel junction of the tooth to the tooth apex. The aim of this study was to measure the height of interdental alveolar bone around the abutment and nonabutment teeth in removable partial denture wearers (RPD) on dental panoramic radiographs (DPR) through a period of six months. Twenty RPD patients (5 males, 15 females participated in the study. The alveolarbone loss measurement was performed on DPRs, using Shei index, on each mandibular abutment and non-abutment tooth on its mesial and distal side, after the RPD delivery and six months later. Recordings of plaque index (PlI) were made at the mid-buccal, mid-palatal, mesio- and disto-palatal surfaces of each abutment and non-abutment teeth after the RPD delivery and six months later. The results revealed a decrease of Shei index values on both abutment and non-abutment teeth, which reached a statistically significant level for distal Shei index values of the abutment teeth and mesial and distal Shei index values of the non-abutment teeth (p<0.05) in a 6 month period. There was no statistically significant difference in PlI values between the first and the second measurement (p>0.05). We concluded that the decrease in bone support on both abutment and non-abutment teeth was attributed to the high levels of PlI and low level of oral hygiene than to RPD loading. Supported by the Ministry of Science and Technology, Republic of Croatia, Project No. 065911

The Rate of Resorption of Different Regions of Residual Ridges in Complete Denture Wearers Dependent on the Region and the Period Following the Last Extraction. One Year Study.

Residual alveolar ridges (RR) show continual resorption after the loss of the natural dentition, resulting in reduction of the morphologic face height and counterclockwise rotation of the mandible, regardless of whether the dentures are worn or not. The aim of this study was to analyse residual ridge resorption (RRR) in 5 different regions of both jaws on the successive lateral cephalograms of 50 complete denture wearers and to correlate such changes with the number of years of edentia and the region where the last extraction was performed. The height of the residual ridges was measured on 5 different sites of the mandible and the maxillary RR using a calibrated grid. The results revealed that all the patients showed significant RRR in the one year period (p<0.01), which was 2.5x more in the mandible than in the maxilla. RRR was bigger in patients who had had their last extraction within a period of one year before receiving their dentures, than in patients who had extracted their teeth earlier (p<0.01). However, the rate of RRR was significantly higher (p<0.01) in the anterior regions of both jaws compared to distal regions (0.41 and 0.42 mm in the incisive/canine region: 0.2 and 0.17 mm in the premolar/ molar region for the maxilla 1.05 and 0.82 mm in the incisive/canine region : 0.27 and 0.11 in the premolar/ molar region for the mandible), even in patients where the last extraction was performed in the premolar region. It seems that the structure of the bone and strains in RR, due to loading from the dentures, may play a role, not only the period following extraction and the region of the last extraction

Analysis of Occlusal Contacts in Different Types of Prosthodontic Appliances, Eichner Classifications, Presence RCP-ICP Slide and the Type of Occlusion

The aim of the study was to determine the number and the type of the occlusal contacts (strong, weak) with respect to the type of the prosthodontic appliance (fixed, removable, combined fixed-removable) and with respect to the Eichner classification in patients with their appliances being in a good function for a long time. The aim of the study was also to determine the number and the type of the occlusal contacts (strong, weak) with respect to the type of occlusion (canine guided, group function or balanced) and the presence of the RCP-ICP slide. A total of 440 patients with different types of prosthodontic appliances were examined for the antagonistic occlusal contacts using occlusal strips of 11 m and 50 m. The average number of occlusal contacts was 10.5 for the upper and 10.46 for the lower posterior teeth, approximately 5 on each side of the tooth arch. The results of the study suggest that the biggest number of occlusal contacts were recorded for the small span fixed appliances (2 on average), the greater span fixed and fixed-removable prosthodontic appliances exhibited 1.6 occlusal contacts, and the removable complete denture exhibited 1.2 contact per the tooth in the posterior region. The number of the hard occlusal contacts was significantly greater in fixed and fixedremovable prosthodontic appliances in comparison with the complete dentures (p < 0.05), while there was no significant difference between the prosthodontic appliances for the weak occlusal contacts (p > 0.05). The overall number of the occlusal contacts, as well as the number of the hard occlusal contacts was significantly greater in the Eichner class I cases (p < 0.05) in comparison with the Eichner classes II and III. The number of the weak occlusal contacts showed no significant differences with respect to the Eichner classification (p > 0.05). There was no significant difference in the number of occlusal contacts between the appliances with RCP-ICP slide and where ICP and RCP corresponded (p > 0.05)

The Rate of Resorption of Different Regions of Residual Ridges in Complete Denture Wearers Dependent on the Region and the Period Following the Last Extraction. One Year Study.

Residual alveolar ridges (RR) show continual resorption after the loss of the natural dentition, resulting in reduction of the morphologic face height and counterclockwise rotation of the mandible, regardless of whether the dentures are worn or not. The aim of this study was to analyse residual ridge resorption (RRR) in 5 different regions of both jaws on the successive lateral cephalograms of 50 complete denture wearers and to correlate such changes with the number of years of edentia and the region where the last extraction was performed. The height of the residual ridges was measured on 5 different sites of the mandible and the maxillary RR using a calibrated grid. The results revealed that all the patients showed significant RRR in the one year period (p<0.01), which was 2.5x more in the mandible than in the maxilla. RRR was bigger in patients who had had their last extraction within a period of one year before receiving their dentures, than in patients who had extracted their teeth earlier (p<0.01). However, the rate of RRR was significantly higher (p<0.01) in the anterior regions of both jaws compared to distal regions (0.41 and 0.42 mm in the incisive/canine region: 0.2 and 0.17 mm in the premolar/ molar region for the maxilla 1.05 and 0.82 mm in the incisive/canine region : 0.27 and 0.11 in the premolar/ molar region for the mandible), even in patients where the last extraction was performed in the premolar region. It seems that the structure of the bone and strains in RR, due to loading from the dentures, may play a role, not only the period following extraction and the region of the last extraction

Type And Material of Fixed Prosthodontic Appliances in Patients Living in the Region of Metković

The aim of this study was to evaluate the type and the aesthetic material in relation to age, gender, level of education, employment, socio-economic status and frequency of visits to the dentist. The examination was performed on 212 patients who had a fixed prosthodontic appliance for more than a year (55% males and 45% females, age 18-80 yrs.). The following conclusions were made: 1. The older patients and retired patients had significantly more bridges than crowns (p0.05). Patients who visit their dentist regularly have significantly more crowns than bridges than patients who visit their dentist irregularly or when in pain (p0.05). 2. Almost all fixed prosthodontic appliances older than 10 years were made of porcelain (98%), while acrylic veneer crowns were more frequent in appliances older than 10 or 15 years (p0.05). Patients older than 60 years had more acrylic material compared to younger patients. While patients younger than 39 years had almost exclusively ceramic appliances (p<0.01). Less educated patients had more acrylic veneer appliances. Employed patients had significantly more ceramic appliances than retired patients

A Method to Evaluate and Compare Two Different Intraoral Radiographs of the Same Patient

Objective of this study was to determine the accuracy of the method of the clinical intraoral densitometry, to compare differences in the calculation with or without subtraction of the background adjacent soft-tissues from the stepwedge (SW) and to verify which regression model best fitted the experimental data in order to express the measured values in equivalents of SW thickness. Two intraoral radiographs, one after another, were made for each of 6 patients. A copper SW (6 steps, thickness 0.05–0.3 mm) was attached to each radiograph, trying to avoid the superimposition of the bony structures. Films were processed and digitized. Grey levels were measured on each step of the SW, on the background of the SW and on the same 3 randomly chosen regions of interest (ROIs) on each digitized image. The measurement with and without the subtraction of optical densities of the background around the SW from the optical densities of the SW was performed. For the calculation of the SW thickness equivalents, the regression analysis was performed by using different regression models. The best fitting regression model was the 3rd degree polynomial. The results were more precise when using the subtraction of the background overlapping the SW

Screening of Fixed Prosthodontic Dentures after Five Years of Use in Relation to Material and Construction

The aim of this study was to screen patients with fixed prosthodontic appliances that were in oral cavity for a period of 5 years or more and to assess clinically and radiologically root caries, gingival recession, pocket formation, alveolar ridge resorption, as well as gingival (GI) and plaque index (PI). The aim also was to find out the differences between materials and constructions, between abutment and non-abutment teeth, and to find out the need for replacement. A total of 260 patients and their orthopantomograms were examined, with a total of 2,265 teeth, 610 being bridge abutments and 246 being crowns. The most frequent were metal+ acrylic veneer crowns or bridges. Root caries was found under the abutments in 10–20%; however abutments with ceramic crowns had the lowest percentage of caries (p<0.01). Alveolar ridge resorption, pocket formation deeper than 3 mm and gingival recession of various degree was found in 50% of the cases, again with the lowest percentage of ceramic-fused-to-metal appliances (p<0.01). Pocket depth was registered in significantly higher percentage in metal-acrylic veneer appliances compared to natural teeth (p<0.01), while there was no significant difference between metal-ceramic appliances and natural teeth (p>0.05). Although the worst findings were recorded for metal-+acrylic veneer crowns for PI, no significant difference existed between crowns of different material or non-abutment teeth (p>0.05). There was statistically significant difference between abutments with metal + acrylic veneer crowns, full metal crowns, metal ceramic crowns and non-abutments for GI scores. Higher percentage of scores 0 and 1 was recorded for metal ceramic crowns and non-abutments and significantly higher percentage of scores 2 and 3 was recorded for metal + acrylic veneer crowns and full metallic crowns. Almost 50% of metal-ceramic abutments had no pathologic findings. Almost 30% of the patients needed replacement, or even some abutments to be extracted and therefore a new prosthodontic appliance

Oral Status, Aesthetic Materials and Frequency of Crowns and Bridges in Patients with Fixed Prosthetic Appliances Living in the Metkovi} Region

The aim of the study was to examine oral status in patients of the Metkovi} region with fixed prosthodontic appliances. The aim was also to evaluate aesthetic materials used, and difference between the frequency of crowns and bridges dependent on patient’s age and frequency of visits to dentist. The examination was performed on 212 dental patients with fixed prosthetic appliances, from the Public Health Center »Metkovi}«. A questionnaire was created for the purpose of this study and was filled in by the patients. The dentist registered oral status. Descriptive statistics and 2 tests were used for the data analysis. Following conclusions were made: 1. The examined patients had relatively high caries (tooth decay), gangrene and residual roots prevalence, the oral hygiene was not appropriate, calculus and gingivitis were diagnosed in all patients (100%) and these facts point out to the insufficient preventive oral health care in the Metkovi} region, as well as to the insufficient self-perception on the proper oral hygiene maintenance. 2. Patients who visit their dentist regularly (once a year or more) have significantly more crowns than bridges than the patients who visit their dentist irregularly or when in pain (p < 0.01). 3. Almost all fixed prosthetic appliances not older than 10 years were made of porcelain (98%), while acrylic veneer crowns (or chromasite) were more frequent in appliances older than 10 or 15 years (p < 0.01). There was no gender difference dependent on the material used (p > 0.05). High frequency of porcelain was attributed to the high economic status of this region, as well as to a dentist’s preference