Effect of Overdenture on Teeth Stability

Effect of Overdenture on Teeth Stability Effect of overdenture with vital and non-vital abutment teeth on the teeth stability Abstract Objective: This study aimed to examine the effect of overdenture over vital and non-vital abutment teeth on the teeth stability. Methods: An experimental study was conducted as non-randomized controlled trial at Faculty of Applied Medical Sciences, Albaha University, Saudi Arabia during 12 months (December 2013 to November 2014). Thirty patients were voluntary participated in this study, first group overdenture over vital abutment teeth and the second group overdenture over non-vital abutment teeth. Attachment loss and teeth mobility were evaluated, after 3 months, 6 months and finally after 12 months. The data were collected from the two groups by questionnaire for demographic characteristics and observation checklist for assessing attachment loss and teeth mobility. The data were then analyzed by computerized method; Statistical Package for Social Sciences, (SPSS version 20). Results: The study showed that the patients have homogenous demographic characteristics. Overdenture over vital abutment teeth showed minimum attachment loss and teeth mobility compared to the overdenture over non-vital abutment teeth. These differences were with high significant statistics Conclusion: It was concluded that, the overdenture over vital abutment teeth was more stable and showed less teeth mobility and less attachment loss than that made over non-vital teeth. Keywords: Overdenture, vital and non-vital abutment teeth, attachment loss and teeth mobility. Introduction: The difference of overdenture from a conventional denture is the precision of dental attachments underneath that gives the overdenture much better retention. In general, the life expectancy of an overdenture is pretty good, and although the process is quite complicated, the benefits far outweigh the cost and time involved.This is because overdenture is very stable and feels more like natural teeth than ordinary dentures.They are also more retentive and help preserve the remaining bone (1). Overdenture could be used with implants or over the natural teeth. The teeth provide good stability for the dentures so that patients feel much better in the same way as natural teeth, and they can be confident that they won’t move around or fall out, alleviating the need to use messy adhesives (2). There is less pressure on the alveolar ridge than with conventional dentures and patients generally feel a lot more confident and can enjoy better health through being able to have better nutrition (2). Many patients with dentures seek for resolution of soreness of bearing tissues and non-stable or retentive dentures, that may increase esthetics, function, comfort, and psychological benefits from implant overdentures, without the need for more extensive fixed restorations (4,5). Overdentures are caries and periodontal diseases of the abutment teeth as bone resorption. Bone resorption in edentulous alveolar processes has been studied extensively, and the conclusion has been reached that it is a chronic, progressive and irreversible process that occurs in all patients (6). As a general rule, four implants are the minimal number in the maxilla in order to remove partial palatal coverage. While maxillary overdenture implants tend to show a slightly higher risk of failure than seen in the mandible, this clearly appears to be related not to the prosthetic design but originates as a direct consequence of compromised preoperative bone, thereby necessitating a reduced number, length, diameter, and angulation of implants (7,8,9). Differences have been observed between individuals in the amount and speed at which alveolar bone is lost, which have been attributed to a diversity of factors such as age, sex, facial anatomy, metabolism, oral hygiene, general health, nutritional status, systematic illnesses, osteoporosis, medications and the amount of time the patient has been edentulous (10,11,12,13). There is a lack of evidence investigating the efficiency of overdenture over vital and non-vital abutment teeth on the supporting structures. This study aimed to examine the effect of overdenture over vital and non-vital abutment teeth on the teeth stability. Methods: An experimental study was conducted at Albaha region, Saudi Arabia during 12 months (December 2013 to November 2014). The study sample consisted of 30 patients (men) with age of 59 years or above. They were partially edentulous for an average of 28 years, and were wearing their third lower denture. The patients selected were free from systemic diseases. The sample was divided into two groups each of 15 patients, both treated with overdenture, but they were different in the abutment teeth, the first group had vital abutment teeth while the second group had non-vital (endodontically treated) teeth. Both groups weared overdentures and evaluated 3 months, then 6 months and lastly after 12 months, as regarding to the attachment loss and tooth mobility of the abutment teeth in a both groups with vital and non-vital abutment teeth. Preparation of the abutment teeth was done as follow; the crown of each tooth was reduced 2-3 mm above the free gingival margin proceeding labially and lingually till a dome shaped. Preparation was obtained with a chamfer finishing line placed subgingivally. The crest of the dome shape was placed over the long axis of the abutment and the sharp points were rounded. This study was approved by the Ethical Committee at Faculty of Applied Medical Sciences, Albaha University (attached). The consents forms were filled by all participants. The right of the participants to withdraw any time was explained and preserved during the study. The data were collected and statistically analyzed. The data were then analyzed by computerized method; (Statistical Package for Social Sciences) (SPSS version 20). The chi-square test was used to test differences in patients’ demographic characteristics in the two groups. The independent t-test was used to identify differences between the two groups. Paired sample t-test was used to measure differences before and after intervention. All values were tabulated as average (mean) with standard deviation (SD). P values less than 0.05 were considered significant with level of confidence 95%. Results summary: As shown in Table (1), thirty patients participated in this study were homogenous in the demographic characteristics. There were insignificant differences in the variables such as age, education level, and years of edentulous, (P > 0.05). As shown in Table (2) and Figure (1), the attachment loss (expressed in mm) in the first group and second group. It was clear from the table that there were significant increases in the attachment loss with time. It also showed that the increases in second group are significantly higher than first group. The table also showed the significant increase of attachment loss and teeth mobility in second group (non-vital abutment) higher than first group (with vital abutment teeth). Table (3) and Figure (1) showed the abutment teeth mobility and bone height (expressed in mm) in the first and second groups. It was clear from the table that there were also significant increases through the time in the abutment teeth mobility and bone height (expressed in mm). It also showed that the increases in second group are significantly higher than first group. Tables and Figures: Table1: Characteristics of group 1 and group 2 patients participated in the study. Variable Group 1 n1 (%) Group 2 n2 (%) P value Education level Illiterate 23 (76.7%) 26 (86.7%) 0.12 Primary 7 (23.3%) 4 (13.3%) Age of patients 59.34  ± 1.76 58.65  ± 2.64 0.65 Years of edentulous 28.12  ± 2.76 27.89  ± 1.67 0.50 Table 2: Comparing the means and standard deviations between the attachment loss for the first group of the vital abutment teeth and second group with non-vital abutment teeth at the different times Variable Group 1 Mean  ± SD Group 2 Mean  ± SD P value Time of evaluation 3 months 0.60 mm  ±0.11 0.97mm ±0.15 0.04* 6 months 0.75 mm  ±0.19* 1.23mm ±0.20* 0.02* 12 months 0.81 mm  ±0.51* 1.54mm ±0.49* 0.01* (*) Significant Table 3: Comparing the means and standard deviations of the tooth mobility between the first group of the vital abutment teeth and second group with non-vital abutment teeth at the different times Variable Group 1 Mean  ± SD Group 2 Mean  ± SD P value Time of evaluation 3 months 0.10 mm  ±0.13 0.16 ±0.15 0.01* 6 months 0.22 mm  ±0.25 0.28 ±0.29 0.01* 12 months 0.48 mm  ±0.51 0.53 ±0.49 0.04* (*) Significant Figure 1: Comparing the means of the attachment loss and tooth mobility between group 1 of the vital abutment teeth and group 2 with non-vital abutment teeth at different times Discussion: This study showed that the attachment loss in the first group with vital abutment is less than the attachment loss in the group with non-vital abutment. It was clear from the findings that there were significant increases in the attachment loss with time in the second group compared to the first group. A study conducted by Gulizio to compare the alveolar bone loss in the anterior segment area with conventional complete denture to overdenture along five years. It concluded that, there was a significant decrease in alveolar bone loss in case of overdenture as compared to conventional complete denture. They attributed this finding to the presence of carried out some studies that shed light on the resorption process that occurred in patients wearing overdentures on both arches (9). Krennmair, in one study on edentulous patients with facial esthetics and associated structures, found that horizontal loss of hard and soft tissue through resorption, disease, or trauma is so advanced that teeth need to be placed far anterior to the residual ridge in order to provide adequate facial support, then an overdenture (ie, acrylic base and flanges) can provide replacement of these structures (14). Moreover, Bryant tested the type of implant prosthesis effect and outcomes for the completely edentulo us patients, and found that no statistical significant differences in premaxillary bone loss. Alternatively, bone grafting procedures can be performed to augment the missing tissues, but limitations must be evaluated (15). Regarding the teeth mobility, this study showed that the abutment teeth mobility and bone height in the first with vital abutment is less than the second group. It was clear from the findings that there were also significant increases in the tooth mobility through the time in the abutment teeth mobility and bone height in the second group compared to first group. Grageda showed that a single implant mandibular overdenture has additional advantages of being less expensive and invasive and significantly increases the satisfaction and quality of life of patients with edentulism (16). The strengths of this study include comparing two different two methods of overdenture, and the long evaluation period (12 months). The study limitations were; the study was conducted among only thirty patients in Al-baha region; such studies will yield more useful results if conducted on more sample size with complete randomization all over the Kingdom of Saudi Arabia. From this study it was concluded that, the overdenture over vital abutment teeth was more stable and showed less teeth mobility and less attachment loss than that made over non-vital teeth.