Comparison of face anthropometry and digital 2D face photogrammetry as a method for predicting vertical dimension of occlusion.

PURPOSE: The objective of the study was to determine the values of 15 craniofacial linear distances in the Serbian ethnic group and the correlations between them that are predictive or can serve as proxy for OVD using and compare two methods of face-anthropometric and digital 2D face-photogrammetric measurement. MATERIAL AND METHODS: A total of 90 adults were selected. Facial distance as a tool to measure the OVD was Sn-Gn - distance between septum of the nose (Sn) and tip of the chin (Gn). Face-anthropometric measurements were made with a Boley Gauge (Buffalo Dental Manufacturing Co.NY,USA). Digital 2D photogrammetric facial measurements were performed using the computer program DrCeph (FYI Technologies, USA). RESULTS: Determined mean value for the distance Sn-Gn by face-anthropometric was Sn-Gn(f) X=63.55 and by face-photogrammetric was Sn-Gn(ph) X=63.56. Multivariate regression analysis revealed that Sn-Gn(f) depended on ExL-ExR(f) p<0.001, ZyL-ZyR(f) p=0.077, N-Sn(f) p=0.096, Sn-Sto(f) p=0.043 and gender and that Sn-Gn(ph) depended on ExL-ExR(ph) p<0.001, EnL-EnR(ph) p=0.029, N-Sn(ph) p=0.013, Sn-Sto(ph) p=0.001 and gender. CONCLUSIONS: A comparison of facial anthropometry and digital 2D facial photogrammetry reveals no statistical significance differences in the values obtained and shows that facial photogrammetry could be a reliable method as a facial anthropometry.

Does the Prevalence of Periodontal Pathogens Change in Elderly Edentulous Patients after Complete Denture Treatment?

PURPOSE: To determine if wearing complete dentures can cause changes in prevalence of some of the most common periodontal pathogens in elderly edentulous patients. The need for understanding the composition of oral microflora in edentulous patients has been recognized by some authors, but no studies have dealt with the changes that occur in periodontal pathogens' prevalence as a result of complete dentures. MATERIALS AND METHODS: A total of 30 edentulous elderly (average age 71) patients participated in the study. Complete dentures were fabricated for each patient, and the residual alveolar ridges were swabbed before denture insertion. After a period of 6 months swabs were taken again. Identification of P. intermedia, A. actinomycetemcomitans, P. gingivalis, T. forsythia, T. denticola, and F. nucleatum was done by the polymerase chain reaction (PCR) method and primers specific for each microorganism. RESULTS: A noticeable increase in the presence of periodontal pathogens was observed after 6 months of denture wearing; targeted bacteria were identified in 17 pre-insertion samples compared to 28 post-insertion samples. The McNemar test was used to compare the prevalence of periodontal pathogenic bacteria before and after dental treatment. p<0.05 indicated statistical significance. Three microorganisms showed a statistically significant difference between the first and second swabbing-A. actinomycetemcomitans (6.7% vs. 40.0%, p = 0.006), P. intermedia (30.0% vs. 73.3%, p = 0.004), and T. forsythia (6.7% vs. 30.0%, p = 0.004). There was also an increase in bacteria co-associations 6 months post-insertion of complete dentures. CONCLUSIONS: The results of the present study suggested that wearing complete dentures caused a considerable increase of periodontopathic bacteria prevalence in elderly patients. Better understanding of oral microflora and the impact dental treatment has on bacterial colonies is important in modern dentistry.

Association Between Dentition Status and Malnutrition Risk in Serbian Elders.

PURPOSE: The aim of this study was to find the correlation between the number, type, and placement of symmetric functional tooth units and the nutritional status using body mass index (BMI) and Mini Nutritional Assessment (MNA) in patients with both maxillary and mandibular removable partial dentures. MATERIALS AND METHODS: A randomized study was conducted at the Clinic for Prosthodontics, School of Dentistry, University of Belgrade, Serbia, followed by determination of number of functional tooth units. After insertion of the prostheses, the nutritional status was assessed, using BMI and MNA form. Nutritional status was reviewed 12 months after prosthetic treatment. Number of teeth and age were analyzed using analysis of variance and t test. For other variables such as BMI baseline, BMI follow-up, MNA baseline, MNA follow-up, change in BMI, and change in MNA, Kruskal-Wallis Test or Mann-Whitney Test were used. RESULTS: The results on the MNA changes showed that patients with symmetric natural functional tooth units had significantly higher values (2.9 ± 0.8) compared with patients without natural functional tooth units (1.9 ± 0.6) or with asymmetric natural functional tooth units (1.6 ± 0.4). Patients with asymmetric artificial functional tooth units had significantly lower change in MNA (1.9 ± 0.4) than those with symmetric artificial functional tooth units (2.6 ± 0.9). CONCLUSION: The findings of this study suggest that adequate rehabilitation with symmetric positioning of the functional tooth units can improve the nutritional status of partially edentulous patients.

Optical aspect of deformation analysis in the bone-denture complex.

The aim of this study was to register and measure any deformation of mandible models under load. The method for full field measurement of strain is done by using the ARAMIS three-dimensional image correlation system. The system uses two digital cameras that provide a synchronized stereo view of the specimen and the results show the complete strain field during the tests. The biggest deformation values were just under the working force of the biggest intensity 500 N, and for the region of the lower second premolar the deformation is 625 microm. The following study is presented that highlight the use of stereometric measuring system for modern research. It is shown that this measuring methodology can capture the trends of the experiments.

Optical metrology analysis of the lower jaw deformations.

BACKGROUND/AIM: New optical stereometric methods based on both contact and noncontact mechanisms for displacement measurement have become common methods in biomechanical behavior research of biomaterials, bone and soft tissue. The aim of this study was to register and measure possible deformations of the lower jaw (mandible) with the intact dental arch using optical metrology method. METHODS: The system for full field measurement of deformations (strains) comprised of two digital cameras for a synchronized stereoview of the specimen, and the Aramis software. RESULTS: The maximum mandibular bone strains were measured in the regions of the lower first premolar and the lower second molar. In the action force of 500 N simulated in the region of the first lower premolar the intensity of deformation was 86 microm. The value of maximum strain in the bone around the molars was 24 microm for the force of 500 N acting on the second lower molar. When it comes to premolars, 3-5 times stronger deformation was observed in the region of the first lower premolar, compared to the deformation values of the second lower premolar area. CONCLUSION: Under loading of the applied forces the measured strains were in the elastic deformation area, meanning that the dependence of force and deformity is linear. The highest values of strain measurements obtained by the optical method were found in the jaw bone tissue around the loading teeth, and the bony regions of the triangle and mental region. According to the obtained results from the Aramis processing software it can be concluded that this method is applicable in a variety of biomedical research.