|Year : 2018 | Volume
| Issue : 2 | Page : 77-82
Tissue stress evaluation at border seal area using patient-manipulated custom tray-modified closed-mouth functional technique for flat mandibular ridges
Sachin Haribhau Chaware1, Francis Fernandes2
1 Department of Prosthodontics, MGV KBH Dental College, Nashik, Maharashtra, India
2 Department of Prosthodontics and Crown and Bridge, MGV KBH Dental College, Nashik, Maharashtra, India
|Date of Web Publication||23-Apr-2018|
Prof. Sachin Haribhau Chaware
Department of Prosthodontics, MGV KBH Dental College, Nashik, Maharashtra
Source of Support: None, Conflict of Interest: None
Aims: Tissue stress evaluation at border seal area using patient-manipulated custom tray-modified closed-mouth functional technique for flat mandibular ridges. Materials and Methods: Thirty completely edentulous participants of either sex, between 50 and 70 years of age, requiring Atwood order number five residual ridge were selected. The materials were used to record tissue stress area includes tissue conditioner (G.C. Reline), pattern resin (LS 1:1 PKG GC America INC for patterning), putty addition silicon (Dentsply Aquasil Soft Putty/Regular Set), and low-fusing compound (DPI Pinnacle-tracing sticks). Custom tray was modified at tray handle area by forming new functional handle to enhance patient motivation to perform functional movements. In total, six areas of tissue stress were evaluated under image analyzer stereomicroscope. Results: All values were subjected to ANOVA statistics. However, descriptive analysis of means of test group (pattern resin: 1.897 mm, low fusing compound: 2.817 mm, and putty addition silicon: 2.410 mm) were significantly different compared to that of control group (tissue conditioner 1.512) (P = 0.000). Mean of tissue stress value recorded by pattern resin was nearer to mean of control group. Conclusion: Custom modified tray technique along with pattern resin records the tissue detail more precisely with minimum tissue stress and greater motivation of the patient to perform functional movements.
Keywords: Flat mandibular ridges, pattern resin, tissue stress
|How to cite this article:|
Chaware SH, Fernandes F. Tissue stress evaluation at border seal area using patient-manipulated custom tray-modified closed-mouth functional technique for flat mandibular ridges. J Int Oral Health 2018;10:77-82
|How to cite this URL:|
Chaware SH, Fernandes F. Tissue stress evaluation at border seal area using patient-manipulated custom tray-modified closed-mouth functional technique for flat mandibular ridges. J Int Oral Health [serial online] 2018 [cited 2019 Mar 20];10:77-82. Available from: http://www.jioh.org/text.asp?2018/10/2/77/230859
| Introduction|| |
Impression making in flat mandibular ridges is a real taxing for a clinician., Measured tissue strain is proportional to amount of tissue stress produce by border molding material. However, in flat mandibular ridges, in spite of marginal tissue stress, there will be corresponding adverse strain generated by peripheral tissue that eventually display in loss of retention and stability of complete denture. To reduce the stress on peripheral tissue, most of the functional impressions manipulate, high- or low-fusing compound, impression waxes, and tissue conditioner.,,,,,,,,, However, to transform adverse tissue strain in more favorable way is to be conditional on functional movements performed by the patient. The more systemic functional movements such as chewing, swallowing, sucking, puffing, blowing, whistling, and smiling, performed by the patient, there will be a successive diminution tissue strain and maintain stable relationship with polished border of the denture. The border molding material must have effective flow, that will continuous for extended period. Tissue conditioner is the only material which satisfies the criteria., However, tissue conditioner needs flat and extended surface proper flow, for the same reason, it is successfully used for abused tissue produce by old ill-fitting denture. Nevertheless, tissue conditioner can be used to find out more suitable border material that reduces the stress on the tissue. Recently, elastomer as well as pattern resin was tested as a border molding material alternative to low-fusing compound. These materials have a properties that record the peripheral details with less tissue stress.,,,
To maintain the tissue stress–strain at peripheral border of the flat mandibular ridge, it is essential to find out the technique that will guide and train the patient to carry out all the functional movements more efficiently, before initiating the border molding. The patient must understand the significance of functional movements for flat mandibular ridges. Similarly, it is equally important to find out the border molding material that will have effective flow, viscosity, and toughness to reduce tissue stress. To achieve this objective, controlled clinical study is needed. In line with this, the study was planned to evaluate tissue stress at border seal area by using patient-manipulated custom tray-modified closed-mouth functional technique for flat mandibular ridges.
| Materials and Methods|| |
It is an experimental study that tests the hypothesis of new technique of functional manipulation performed by the patient and tissue stress induced by the new materials. The study protocol was reviewed by the ethical committee of the institute and clearance for the same was obtained. Thirty completely edentulous subjects of either sex, between 50 and 70 years of age, requiring Atwood order five edentulous ridge was selected. Medically compromised patient, geriatric patient, patient with poor neuromuscular balance, and patient who is not willing to take part in the study were excluded from the study. The study protocol was explained to the patient and consent was taken for the same. Infection control protocol was planned properly.
Preliminary impression was made with irreversible hydrocolloid (company) in perforated rim-locked tray and primary casts were fabricated by using type III gypsum product (Gyprock) [Figure 1].
Modified custom tray design
The custom tray was fabricated with vacuum formed thermoplastic sheets (Bio star). The tray was modified at the tray handle area. Initially, conventional handle was prepared in the midline of custom tray. Height, length, and width of the handle were 8, 8, and 3–4 mm, respectively [Figure 2].
The second handle design was the flat extension of acrylic resin from the conventional handle, outside the mouth. The purpose of the second handle is to carry out functional movements such as lip and cheek movements and swallowing and sucking movements by guiding the patient, to concentrate on the second handle. Hence, the second handle is also known as a “Functional Handle.” The functional handle was fabricated with heat cured acrylic resin. The length of the functional handle is 70 mm and thickness is 3 mm just at the point of attachment to the screw and gradually increases in thickness to about 8 mm toward the end [Figure 2].
The small screw, which is approximately 8 mm in height and 3 mm in diameter, was used to join the functional handle to the conventional handle. The junction between functional handle and conventional handle was of a semi-fixed type so that functional handle can move freely from right corner to left corner of the mouth. Total four custom trays were fabricated from each diagnostic cast, as there were four border materials were used for the study [Figure 2].
Preborder molding exercise
Initially, tray was placed inside the patient mouth and patient was told to hold the functional handle at the center of the mouth. The patient was instructed not to perform any functional movements, just keep the tray in the mouth for 5–10 min, so the patient will get familiarized and better adjusted with custom tray. Swallowing and chewing functional movements were performed first by keeping the handle at center of the mouth. The patient was instructed to concentrate on handle while doing the functional movements; this particular movement was used to record labial flange and anterior lingual flange. It stimulates the genioglossus and geniohyoid lingually and orbicularis oris labially. Afterward, functional handle was moved to the left corner of the mouth, and the patient was instructed to move slowly the right lip, right cheek, and tongue to the left corner of the mouth by concentrating on the handle; this particular movement was used to record right buccal flange and right lingual flange to retromylohyoid area. It stimulates buccinators, massater, mentalis, and orbicularis oris on the right buccal area and mylohyoid and certain extent palatoglossus on the right lingual area. Similar procedure but opposite movements was carried out to record left buccal and lingual flange. Finally, distolingual flange was recorded by instructing to do swallowing movements bilaterally that will stimulate palatoglossus bilaterally. The patient was given sufficient time to perform all the movements, so there will be no fatigue at the end of the procedure [Figure 3].
|Figure 3: Functional movements performed by the patient using functional handle|
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Four border materials were used for the study, which are divided into Group 1 (control group): Tissue conditioner (GC reline) was used for this group, Group 2 (test group): pattern resin (Group 2: LS 1:1 PKG GC America INC for patterning), Group 3: addition silicon putty (Dentsply Aquasil Soft Putty/Regular Set), and Group 4: low-fusing compound (DPI Pinnacle-tracing sticks).
Sectional border molding was carried out. Initially, labial flange was recorded, followed by the right buccal flange and left buccal flange. On the lingual side, anterior lingual flange was recorded first followed by right and left posterior lingual flange and finally distolingual flange was recorded [Figure 4].
Tissue conditioner border molding was carried out by placing the material on inner border of the tray and then gradually extended to edge of the custom tray, so the material will get sufficient area to flow. The reaming excess that spread towards ridge area was separated by sharp knife. Pattern resin border molding tray was removed from the patient mouth, just to the end of polymerization, to prevent the heat transfer intraoral.
After the border molding, the denture impression was removed, washed, and disinfected. The border molded tray was put on the bench top, and points were marked 2 mm below from the highest point of border along the periphery. All these points were joined to form a line 2 mm below the border. A beading wax was then placed in the line to achieve a 2 mm uniform border [Figure 5]. All beaded impressions were lubricated with petroleum jelly and then poured in Type IV gypsum product (die stone).
|Figure 5: Uniform 2 mm line to peripheral border of the tray for beading wax|
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Casts were retrieved and a vacuum formed sheet was adapted on the cast. A string was adapted along the crest of the ridge. The entire string length was measured with a scale. After that, the string with marks was placed on the cast and vacuum formed template was placed on the top of it and holes were made on the template according to the markings on the string. This template with holes was then used for other casts. The marks were placed using the holes on the template and lines were drawn on those casts. The casts were then sectioned along these lines to obtain equidistant sections, which are as follows [Figure 6].
- From canine to canine
- Left-side posterior region
- Right-side posterior region.
Under image analyzer, depth was measured from the Descriptive and ANOVA statistics are summarized in [Table 1] portion of the ridge to the lowest point of the sulcus in all the areas, namely, anterior labial, anterior lingual, left posterior buccal, left posterior lingual, right posterior buccal, and right posterior lingual [Figure 7] and [Figure 8].
|Figure 8: Photographic images of tissue stress depth produces by various border-molding materials|
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The total area was measured as cumulative average of the entire area. The average measurement of the total area for all the sections was taken as the final measurement for that material in those patients. All the obtained data were entered into a personal computer on Microsoft excel sheet and analyzed using the software Statistical Package for the Social Sciences (SPSS; IBM, USA) version 20. Data comparison was carried out by applying ANOVA test. The statistically significant level was fixed at P < 0.05.
| Results|| |
Descriptive and ANOVA statistics are summarized in [Table 1]. It has been observed that there was statistically significant difference between the depth of tissue stress produced by the three materials when compared with the control group, P = 0.000 [Table 1]. It is also observed that mean of Group 1 (Pattern resin) was nearer to the control group, suggesting that pattern resin records better depth of the tissue stress, compared to rest of the materials [Graph 1].
Multiple comparison of tissue stress values within groups using post hoc Bonferroni test is summarized in [Table 2]. The mean difference of tissue stress values was statistically significant (P = 0.000) when Group 1 was compared with Group 3 (0.8980) and Group 4 (1.3040) than Group 2 (0.3850). Similarly, mean difference was significant (P = 0.000) when Group 2 was compared with Group 3 (0.5130) and Group 4 (0.9200).
|Table 2: Multiple comparison of tissue stress values within groups using post hoc Bonferroni test|
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| Discussion|| |
Complete denture should remain retentive and stable in all functional movements performed by the patient, irrespective of height and width of residual ridge. Border tissue of flat mandibular ridges shows unfavorable strain to applied stress of border molding material. It is observed that tissue strain is subject to functional movements performed by the patient. Hence, it is essential to find out the technique that will guide and train the patient more efficiently. Recently, a clinical case report was published in that custom tray was modified at the handle area by connecting the additional handle to existing handle of the custom tray using a small screw. The connection between the additional handle and existing handle was semi-fixed type so that additional handle can be moved from left to right corner of the mouth. Authors of the case report suggested that this modified method trains the patient more efficiently by concentrating on the additional handle. However, it is equally important to find out the suitable border molding material that produces less stress on border tissue, as new material that routinely used for conventional border molding alternative to low-fusing compound also has chance to use for flat mandibular ridges. On the similar line, the study was planned to evaluate tissue stress of border seal area using patient-manipulated custom tray-modified closed-mouth impression technique for the flat mandibular ridge.
The study population was selected on the basis of convenience nonprobability sampling technique, as no previous study had estimated the mean values of the measured variables. The randomized block design was decided to be used while selecting the inclusion criteria for the study, to minimize the bias of unwanted variability; hence, the Atwood order five edentulous ridge was selected as an inclusion criteria.
The four materials were used to evaluate the depth of the tissue stress that are divided into a Group 1 (Control group): tissue conditioner (GC Reline), Group 2 (Test group): pattern resin (Group 2: LS 1:1 PKG GC America INC for patterning), Group 3 (Test group): addition silicon putty (DentsplyAquasil Soft Putty/Regular Set), and Group 4 (Test group): low-fusing compound (DPI Pinnacle-tracing sticks).
It is difficult to determine the exact level of depth of the tissue stress produced by border-molding materials. Hence, tissue conditioner was selected as a control group material (Group 1) to compare amount of stress produced by test materials. Tissue conditioner exhibits the property that it continuously flows for extended period of time and gives exact border details of the tissue with minimum tissue stress. To use the material, a flat or an extended surface such as denture base or old denture is required. However, in the present study, the material was placed on inner areas of the tray border as maximum as possible and then extended to the edge of the custom tray.
Custom tray was modified at tray handle area as per the design given by Malachias et al. The additional handle was named in the study as “functional handle” as patient concentrates on functional handle while performing the functional movements. The patient was guided to perform all the functional movements using functional handle and sufficient time was given to the patient to train himself for the same. Sectional border molding was carried out so that patient will get sufficient time for adjustment and there will be no fatigue at the end of the procedure.
Depth of the tissue stress was evaluated under image analyzer, and one area from each section of border molding was selected. A total six areas were selected to evaluate depth of the tissue stress.
Results of the study show highly significant means when compared with different groups (P = 0.000). It means control group records least tissue stress than test materials. However, descriptive means shows that pattern resin means are very closer to the control group and indicates that pattern resin records lower tissue stress than rest of the materials. Technically pattern resin is easy to manipulate, easy to apply, and generically material belongs to resin family, so it produces strong adhesion with acrylic tray border. The most unique property with pattern resin is that it has an effective flow. The flow of pattern resin is uniform, unidirectional, and almost similar to tissue conditioner. Pattern resin records the tissue detail in thinner section, and still, it maintains its toughness. Pattern resin not only reduces the tissue stress but also the patient is also highly comfortable while performing the functional movements. Polymerization heat and contraction is not a significant problem for border molding. The material has sufficient working time, so most of the functional movements were completed before the end of the polymerization and rest of the polymerization completed outside. Polymerization contraction of pattern resin is negligible as compared to other denture base resins. Manufacturers of pattern resin also documented that initial set contraction and final set contraction are negligible. Due to this valuable property, it is a recommended material for direct or indirect post and core and direct or indirect inlay pattern. Patel et al. recommended that pattern resin records better border morphology than silicon putty and low fusing compound. The study was conducted on maxillary border area with well-developed ridge. Pattern resin does not produce any tissue insult. However, it contraindicates in residual ridge with tissue undercut.
Silicon putty recorded higher mean than control group. Putty is highly filled, high viscosity, and bulk material. Putty is easy to manipulate and easy to adapt (60-70%). However, putty needs more pressure to flow. Putty has multidirectional and aberrant flow. Hence, it produces vertical as well as lateral tissue stress. Similarly, the patient experiences much difficulty while performing functional movements, particularly labial and buccal flange. Several authors reported that putty records the border in single step, easy to manipulate, reduces chair time, good tear strength, and accurate reproduction of undercut areas. All these studies were conducted on well-developed ridges.,, However, Qanungo et al. show that putty records inferior retention value than low fusing compound. Border morphology study by Patel et al. suggested that putty produces extremely thick border and this is unacceptable for clinical use.
Low-fusing compound recorded the highest mean than rest of the materials used in the study. Low-fusing compound is thermoplastic and brittle material. The flow of the material is eccentric and highly aberrant. The flow depends on the amount of heat retained with the material. Patient had much difficulty to carry out the functional movements. Most of the patients got fatigue at the end of the procedure, as the tiring clinical step and heat involves during functional manipulation.
Clinically, how patient performs precise functional movements without fatigue and effective flow of the border molding material are important factors to maintain favorable stress–strain ration at border seal area of flat mandibular ridges. The present study shows that modification of custom tray at handle area by forming new functional handle increases the patient confidence. Patient, self-motivated, understands the importance of functional movements and limitations of flat mandibular ridges. Tissue conditioner and pattern resin have uniform and unidirectional flow. These materials produce minimal tissue vertical and lateral stress. Functional manipulation performed by patient with much comfort. However, to use tissue conditioner required denture base or old denture. Addition silicon putty and low-fusing compound have multidirectional and aberrant flow. Hence, both materials produce maximum tissue stress, in vertical as well as in lateral direction. Putty required maximum pressure to deform the material and low-fusing compound rigid quickly inside the mouth and heat involve while functional manipulation. Patient experiences much difficulty with both of these materials. Further research is needed to evaluate critical analysis tissue morphology at border seal area along with material properties of border-molding material.
| Conclusion|| |
It can be concluded within limitations that patient-manipulated custom tray-modified closed-mouth functional technique may be a useful technique to exercise the patient for various functional movements, before recording the border seal area for flat mandibular ridges. Similarly, pattern resin may be useful border molding material to record the tissue details with minimum tissue stress and greater patient comfort. Addition silicon putty and low-fusing compound produces higher tissue stress with maximum discomfort experienced by the patient.
The present study was self-funded by the authors. Furthermore, we, the authors of this study, thank all the patients, who took part in this study for their cooperation.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
[Table 1], [Table 2]