Do They Work?
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February 1, 2012
Volume 3, Issue 2, February 2012
Page(s):
A clinical study on patients conducted in Hani Sal Badra's article on "The effect of ultra suction system on the retention of mandibular complete denture" and published in January 2010 of the Egyptian Dental Journal, concluded that the UltraSuction system increases the retention of mandibular dentures.1 To prove this, he carried out a study on seven completely edentulous patients selected from the Prosthodontic Department, Faculty of Oral and Dental Medicine, Cairo University. The age of the selected patients ranged from 45 to 65 years and all of them were selected to be free of systemic and oral diseases, especially those that might affect the retention of the denture, such as neuromuscular disorders, diabetes mellitus, and/or xerostomia. Their residual ridges were covered by firm healthy mucosa and exhibited no unilateral or bilateral undercuts to eliminate the effect of the latter on the retention, and to facilitate the performance of the retention test. Patients also had an angle class I maxillomandibular relationship, normal tongue size, and were free from any temporomandibular joint problems. For each patient, one maxillary and two mandibular complete dentures were constructed, namely set I and II dentures.
Set I was represented by conventional mandibular dentures. Set II was represented by the UltraSuction retained mandibular dentures. Set I dentures were first delivered to patients who were left to function with these dentures for a period of a month during which they were recalled for alleviating any complaint, checking occlusion, and testing denture retention. Set II dentures, however, were delivered after a resting period of about 2 weeks to 1 month, during which patients were left completely without the dentures. This period allowed for tissue rebound. Patients were then allowed to function with the new set of dentures for the same period as Set I, namely 1 month.
It has been documented that the measurement of complete denture retention was best attempted by pulling the denture from its geographic centre.2 Hence, it was essential to locate this center for both sets. Three lines were drawn on the cast to aid in determining the geographic center of the cast; line 1 connecting two points at the apices of the retromolar pads of both sides of the arch, line 2 passing through the crest of the anterior ridge and parallel to the line 1, line 3 passing through the midline of the cast and perpendicular to both lines 1 and 2, point A, the midpoint between line 1 and 2 drawn on line 3, line 4 passing through point A and running parallel to lines 1 and 2 . At this point, a hole was drilled on the cast by the aid of a surgical round bur.
Three orthodontic brackets were attached to the lingual aspect of the denture, one at its midline and two posteriorly where line 4 passed through them. Three metallic wires, each with an 18-gauge diameter as advocated by Burns et al,3 were engaged by three lingual brackets and extended upward to meet the geographic center of the denture, which was easily identified by the surgical bur projecting from the cast base. A metallic loop was then used to join the three wires on the top of the bur.
The retention measurement test was performed for each set of dentures at the time of insertion—1 week, 2 weeks, and 1 month after delivery. The test began only after the patient was allowed to bite on his dentures to expel any air trapped beneath the denture base. The retention was measured by a specifically designed retention testing device (Eagle ELT 3000). The device is digital and can apply forces in upward and downward directions. It has a minimum reading of 20 g and a maximum reading of 5,000 g with a good to very good (0.778–0.998) reliability. It consists of a metallic probe that applies the force and is connected to the device by an electric wire. The base has a digital screen which gives positive and negative readings according to the direction of forced applied. The device applies a vertical pull-off load on the metallic loop joining the wires. Values at which the denture was dislodged were recorded. The pull-off procedure was repeated 10 times to obtain 10 records for each, the mean of which was calculated.
The recorded mean values were tabulated and statistically analyzed using SPSS 16.0 (Statistical Package for Scientific Studies) for Windows. A paired t-test was used to compare the mean retention values obtained for each set of dentures at the different follow-up visits and to compare the retention values of both denture sets. Results were considered significant at P ≤ .05.
The comparison between the mean retention values of Set I and II dentures revealed a statistically significant increase (P ≤ .05) in the retention after the application of the UltraSuction system at all follow-up visits (1, 2, and 4 weeks) (Table 1). On the other hand, studying the effect of time on the mean retention values obtained for both sets of dentures (I and II) revealed a statistically significant increase in the retention by time (P ≤ .05) (Table 2).
