Occlusal vertical dimension in removable complete dentures

In removable complete dentures, the occlusal vertical dimension is an important factor for patients' satisfaction with aesthetics. An excessively reduced occlusal vertical dimension is especially likely to lead to complaints about aesthetics, whereas an increased occlusal vertical dimension may lead to discomfort and a decision not to wear the complete dentures. There are various methods for determining the occlusal vertical dimension in complete dentures, based on the vertical dimension in the rest position of the mandible or on phonetics. However, none of the methods have proven to be clearly superior, in terms of reliability, than the others. The assessment of the occlusal vertical dimension will become more reliable if several methods are used simultaneously. Moreover, knowledge of the characteristics of the ageing face is essential.     

Changes in occlusal vertical dimension in microwave processing of complete dentures

This study investigated the effect of different microwave curing cycles on the changes in occlusal vertical dimension of complete dentures. Four test groups with 12 maxillary dentures each were evaluated. Groups 1, 2 and 3 were polymerized with different cycles by microwave radiation and Group 4 was the control and cured by water bath. The average pin opening for all groups was less than 0.5 mm. There was no significant difference between the groups polymerized by the microwave method and the control group. However, analyses of the vertical dimension changes showed statistically significant differences between groups 2 (0.276 +/- 0.141 mm) and 3 (0.496 +/- 0.220 mm).     

Copying maxillary anterior natural tooth position in complete dentures.

The natural teeth provide the optimal guide for the correct placement of artificial teeth. A stent is made on the patient's maxillary preextraction diagnostic cast. The stent is transferred to the patient's edentulous maxillary cast to help position the maxillary anterior artificial teeth in the same positions the maxillary natural teeth occupied before extraction.     

Effects of cast-gold mandibular dentures on the vertical dimension of rest position

This investigation compared the weight of gold-base lower dentures with the weight of the hard and soft tissues lost by patients with residual ridge resorption. The vertical dimension of rest position was determined electromyographically and checked at intervals following the wearing of mandibular dentures with gold bases. The five patients in this study demonstrated an average 0.9 mm. increase in their vertical dimension of rest position. This increase appeared to be well tolerated, and all patients adjusted well to their dentures.     

Comparison of changes in vertical dimension between compression and injection molded complete dentures

Complete dentures were made for 30 patients. Fifteen sets were processed by conventional compression molding and 15 sets were processed by using the SR-Ivocap injection system. Changes in vertical dimension between the waxed and processed dentures were measured at the incisal guide pin by using a dial indicator. The difference between the two methods was highly significant on the basis of t-test statistics. Whereas the processing changes noted with the conventional pack-and-press method were similar to previous studies, the injection method produced little or no pin opening. The superiority of the injection method before decasting was indisputable, and the results suggest that the laboratory remount procedure may be unnecessary when this system is used.     

Changes in vertical dimension of occlusion in conventional and microwave processing of complete dentures

An investigation was made to compare the increase in vertical dimension of occlusion in complete dentures after processing with conventional and microwave procedures. Lucitone-characterized denture base material was used for 15 sets of complete dentures cured conventionally. Justi-characterized acrylic resin and microliquid were used for 15 sets of complete dentures cured by the microwave procedure. The results of the study showed increases in vertical dimension of occlusion in both methods under 1 mm, which is considered technically acceptable. However, a statistically significant larger increase was present in the microwave technique.     

The relationship of vertical dimension of atypical swallowing with complete dentures.

A number of subjects were studied cineflourographically during swallowing, and their vertical dimensions of occlusion were clinically evaluated. The subjects who had reduced vertical dimensions of occlusion were older than those with normal vertical dimensions, their dentures were older, their total years with complete dentures were more, and the tendency to swallow without opposing tooth contact was greater. The cumulative evidence indicates that such aberrant muscle activity might contribute to the regressive changes found in complete denture wearers.     

Effect of water storage on tooth displacement in maxillary complete dentures

The purpose of this study was to investigate the effect of water storage at 37 degrees C (1 week, 1 month and 3 months) on tooth displacement in maxillary complete dentures. Ten maxillary dentures were constructed with Clássico acrylic resin using the conventional method of packing in metallic flasks. Metallic reference pins were placed in the incisal border of the central incisors (I), labial cusp of the first premolars (PM), and mesiolabial cusp of the second molars (M). Twelve hours after final flask closure, the acrylic resin was cured in water at 74 degrees C for 9 h. The flasks were removed from the thermo-polymerizing unit after water-cooling and the dentures were deflasked, finished and stored in water at a temperature of 37 degrees C for 1 week, 1 month and 3 months. At deflasking and at the water storage intervals, the I-I (incisor to incisor), PM-PM (pre-molar to pre-molar), and M-M (molar to molar) transversal distances, and LI-LM (left incisor to left molar) and RI-RM (right incisor to right molar) anteroposterior distances were measured using an optical microscope with 0.0005 mm accuracy. Data were submitted to ANOVA and Tukey's test (5%). Comparing the evaluation periods for each individual transversal and anteroposterior reference point, no statistically significant differences were observed among deflasking and the water storage intervals for I-I, PM-PM, M-M and RI-RM distances (p>0.05). For LI-LM, however, deflasking values were statistically different from those of 1-week, 1-month and 3-month water storage intervals (p<0.05), which, in turn, did not differ statistically to each other (p>0.05). These results confirm the complexity of tooth displacement in complete dentures. From a clinical standpoint, the difference observed in LI-LM distance after water storage would not be detected by the patients during clinical use.     

Effect of immediate complete dentures on tooth eruption and jaw development

Dental treatment of a 4-year-old boy included the extraction of all deciduous teeth and construction of immediate complete dentures to serve until the permanent teeth erupted. Important findings from follow-up examinations of this patient follow.

1.

1. The patient, at this young age, tolerated and accepted the complete dentures very satisfactorily.     

Determination of occlusal vertical dimension for complete dentures patients: an updated review

Determination of the occlusal vertical dimension (OVD) is an integral part of complete dentures fabrication. Due to the lack of teeth, the clinician faces the challenge of how to accurately establish the OVD of the new denture. Therefore, the purpose of this review article was to present, discuss and critique the available methods used in determining the OVD for complete dentures patients. This review identified two main streams to determine the OVD: (i) pre‐extraction methods and (ii) post‐extraction methods. For the pre‐extraction methods, the OVD of the natural dentition is transferred to the new dentures mainly by intra‐oral measurements, profile tracing and cephalometric analysis. The post‐extraction methods rely on mandibular rest position, facial aesthetic appearance, swallowing pattern, craniofacial landmarks measurements, cephalometric analysis, phonetics and existing dentures. In general, all the available techniques have merits and are helpful for routine clinical use. However, they are empirical in nature, controversial and lack the scientific support. Further, there is no single accurate method for OVD determination. To overcome the limitations of the techniques, the clinician will benefit from applying combination of techniques to approximate the OVD.     

Effect of denture thickness on tooth movement during processing of complete dentures

In this investigation the effect of denture thickness on tooth movement during processing of complete dentures was studied. A maxillary cast from a patient was duplicated to obtain 10 identical casts. Base plates were constructed on five casts using 1·25 mm thick wax. Base plates were constructed on the other five casts using 2·5 mm thick wax. Teeth were placed on the ridge of each cast and a TMS pin was placed vertically, upright, in each tooth. The dentures were invested, cured, decasted, finished and polished. Each denture was radiographed immediately before processing, after deflasking, on removal from the cast and after finishing and polishing using a standard technique. The radiographs were digitized using an Eikonix image digitizer. The results showed that there were significant variations in tooth movement between thick and thin denture bases. Also an increase in the molar‐to‐molar distance was found in both the thin and thick dentures but the magnitude of tooth movement was more in thick dentures.     

Comparison of immediate complete denture, tooth and implant-supported overdenture on vertical dimension and muscle activity

PURPOSE

To compare the changes in the occlusal vertical dimension, activity of masseter muscles and biting force after insertion of immediate denture constructed with conventional, tooth-supported and Implant-supported immediate mandibular complete denture.

MATERIALS AND METHODS

Patients were selected and treatment was carried out with all the three different concepts i.e, immediate denture constructed with conventional (Group A), tooth-supported (Group B) and Implant-supported (Group C) immediate mandibular complete dentures. Parameters of evaluation and comparison were occlusal vertical dimension measured by radiograph (at three different time intervals), Masseter muscle electromyographic (EMG) measurement by EMG analysis (at three different positions of jaws) and bite force measured by force transducer (at two different time intervals). The obtained data were statistically analyzed by using ANOVA-F test at 5% level of significance. If the F test was significant, Least Significant Difference test was performed to test further significant differences between variables.

RESULTS

Comparison between mean differences in occlusal vertical dimension for tested groups showed that it was only statistically significant at 1 year after immediate dentures insertion. Comparison between mean differences in wavelet packet coefficients of the electromyographic signals of masseter muscles for tested groups was not significant at rest position, but significant at initial contact position and maximum voluntary clench position. Comparison between mean differences in maximum biting force for tested groups was not statistically significant at 5% level of significance.

CONCLUSION

Immediate complete overdentures whether tooth or implant supported prosthesis is recommended than totally mucosal supported prosthesis.