Dr. Srushti S. Shah, Dr. Ashutosh Pai, Dr. Bhavna Ahuja
Department of Prosthodontics and Crown & Bridge,
T.P.C. T’s Terna Dental College, Navi Mumbai
Managing flabby ridges has always been a challenge while restoring completely edentulous ridges. Fibrous alveolar ridges pose significant problems for the provision of stable and retentive dental prosthesis. Main challenge arises while making impressions of such flabby tissues. Different mucostatic impression techniques like employing a window tray technique, multiple relief holes, or double spacers can be used when the flabby tissue is localized. Above mentioned techniques are indicated mainly in cases with localized flabby tissues.
This article presents a clinical report of a patient with generalized flabby maxillary and mandibular edentulous ridges. A split two-part special tray using the principle of magnetic attraction for self-retention with retentive holes was fabricated for maxillary arch. This self-retention ruled out finger pressure during impression making thus, helping to achieve mucostatics. For mandibular arch, conventional window technique was used.
Keywords: Flabby tissue, fibrous ridge, denture stability, mucostatic impressions, magnetically retained custom tray.
Citations: Shah S, Pai A, Ahuja B. A Novel Technique for Management of Flabby Ridge Using Self-Retaining Custom Trays: A Case Report. J Prosthodont Dent Mater 2021;2(2):70-77.
A denture flying out of someone's mouth might be a staple of slapstick comedy but it is not beyond realistic fear of the patient with a complete denture. Dislodgement of dentures while socializing is a nightmare, edentulous patients live with. A complete denture prosthesis is the treatment of choice, globally, to improve masticatory ability and enhance the oral health of patients with edentulism. Edentulous patients have reported difficulty in performing daily activities after a period of denture use. Most chief complaints were due to an ill-fitting denture. The main factors determining the success of the complete denture prosthesis are retention, stability and support.
Hard and soft tissues play a very important role in determining these factors. However, whether the retention and/or stability in maxillary or mandibular or both dentures have a greater impact on patient-based treatment outcomes. Restoring dental and alveolar structures for geriatric patients is more preferable over surgical management.
A flabby tissue is an excessive mobile tissue. A ‘fibrous’ or ‘flabby’ ridge is an unsupported area of mobile soft tissue affecting the maxillary or mandibular alveolar ridges. It can develop when hyperplastic soft tissue replaces the alveolar bone. This is a common finding, particularly in the maxillary anterior region in long - term denture wearers or in cases of combination syndrome. Flabby tissue causes lack of stability and support to the complete dentures. In 1970, Watson discussed this phenomenon and described an impression technique for maxillary flabby ridges.
Kelly in 1972 suggested the term “combination syndrome” which describes the changes caused by a mandibular removable partial denture opposing a maxillary complete denture. The clinical features of this syndrome included;
(1) Loss of bone from the anterior part of the maxillary ridge,
(2) Overgrowth of the tuberosities,
(3) Papillary hyperplasia in the hard palate,
(4) Extrusion of the lower anterior teeth,
(5) The loss of bone under the partial denture bases.
Conventional impression techniques have an impact while recording the flabby tissues and hence, various techniques have been described in the literature for making impressions of fibrous ridges such as Osborne technique (1964)4, Liddlelow technique (1964)5, Zafarullah Khan technique (1981), Watt and McGregor technique (1970)6, Hobkirk technique (1997). The technique used in this article provides a complete mucostatic impression procedure for making impression of flabby ridges.
From clinical perspective, it is challenging to make removable complete dentures for flabby maxillary and mandibular ridges and hence the purpose of this article is to present a novel procedure for making complete mucostatic impressions for maxillary and mandibular flabby ridges using magnets and window technique respectively.
A 65-year-old male patient reported to Department of Prosthodontics crown and bridge, Terna Dental College, Navi Mumbai, Maharashtra with the chief complaint of broken maxillary complete denture and wanted replacement of the same. Patient is a denture wearer since 8-9 years and is currently wearing complete denture prosthesis that was fabricated 3 years back. No medical history was noted.
Intraoral examination revealed completely edentulous maxillary and mandibular arches. Ridge mucosa of both the arches showed generalized hyperplastic mucosal tissue with varying degree of displaceability. There were various treatment options that were suggested to the patient which included surgical management of fibrous tissue prior to conventional prosthodontics, fixed/removable implant retained prosthesis and conventional prosthodontics without surgical intervention.
Surgical management required ridge augmentation and vestibuloplasty procedure. As this would lead to tissue and bone loss after the surgery, prosthodontic management with complete mucostatic impression technique for maxillary and mandibular arches and stable occlusal contacts was planned.
Preliminary impressions for both maxillary mandibular arches ware made using perforated metal stocked tray and irreversible hydrocolloid (Tropicalgin, Zhermack). Impressions were poured using dental stone. Due to presence of hypermobile tissue, there was instability while placing the tray and hence a mode of stabilization for custom tray was needed while making final impression. So, a specialized custom tray for maxillary arch was fabricated using magnetic retention to ensure a complete mucostatic final impression. For mandibular arch, conventional window technique final impression was decided and the custom tray was fabricated in that manner. Custom trays were fabricated using autopolymerising acrylic resin tray material in the following manner.
FOR MAXILLARY ARCH:
Custom tray fabrication was done in two parts i.e., TRAY-A and TRAY-B corresponding to the degree of displaceability of the mucosal tissue. Region-A that was relatively stable consisted of palatal vault while Region-B consisted of generalized mobile tissue on the residual alveolar ridge. So, TRAY-A was the palatal section tray while TRAY-B was ridge section tray.
TRAY-A (PALATAL TRAY) FABRICATION:
Adaption of single thickness modelling wax was done on the region-A with 4 rectangular tissue stops; 2 on either side of the midline on the slopes of palate. Tray-A was made on this with auto polymerising tray material (Asian Special Instant Tray Material, Asian acrylates, Mumbai, India). The tray extended into region-A up to the hamular region of the notch on the cast. 2 depressions were made along the midline of the tray; one anteriorly and the other posteriorly and rare earth square magnets of 10mm x 10mm x 2mm were placed and secured in the respective depressions (magnets denoted as AM1 and DM1). A 10mm x 6mm x 6mm handle was made in between the magnets which could be used for securing the tray in place intraorally.
TRAY-B (RIDGE TRAY) FABRICATION:
2 layers of modelling wax were adapted on the region-B and a custom tray was fabricated 2mm short of the sulcus depth. Tray was extended along the midline where 2 rare earth square magnets (10mm x 10mm x 2mm) were placed to engage AM1 and DM1 of tray-A. These magnets will be denoted as AM2 and DM2. Hole was made between the two magnets that would fit in the handle made in Tray-A. Tray handle was made in the center of the ridge area at 450 on this tray.
Margins of both the trays were beveled at their contact areas so as to get an intimate contact of both the trays while seating. The trays A and B were then placed on the diagnostic cast in their respective areas. The trays remained stable in their position due to the attraction forces between the unlike poles magnets in respective trays i.e. AM1 against AM2 and DM1 against DM2.
FOR MANDIBULAR ARCH:
Custom tray was fabricated in conventional manner for mandibular arch after adapting a layer of modelling wax.
IMPRESSION TECHNIQUE FOR MAXILLARY ARCH:
Trays A and B were placed intraorally to check for its proper seating and extensions. Sectional border molding was performed using low fusing impression compound (Pinnacle tracing stick, DPI, Mumbai, India) along the posterior palatal seal area of tray-A and borders of tray-B with the trays assembled together to achieve a proper seal. Trays were stabilized by finger support in region-A while border molding. After completion, both the trays were detached for making final impression. Placement and orientation of trays A and B in stages were rehearsed many times so the tissues would be recorded at rest without any disturbance from the operator’s finger pressure.
Impression of region-A was first made with monophase (medium body) (Aquasil LV Monophase, Dentsply Caulk) addition silicone on tray-A after adhesive application and stabilizing it with the handle intraorally. The tray was then removed and excess was cut off using sharp scissors. And the tray was reseated back in the mouth.
Multiple holes were drilled on tray-B to provide mechanical retention for the elastomer. Tray adhesive was applied. Monophase (medium body) (Aquasil LV Monophase, Dentsply Caulk) addition silicone was then injected along the tray-B and was oriented along the tray-A intraorally in such a way that unlike poles of the magnets of both A and B trays faced each other (AM1-AM2 and DM1-DM2). Tray-B was released when the power of the magnet was felt. It was self-retained because of the magnetic pull and no finger pressure was then required. Once the impression material was completely polymerized, the entire tray assembly was then removed from the patient’s mouth. Surface details were appreciated on the impression that was recorded.
IMPRESSION TECHNIQUE FOR MANDIBULAR ARCH:
Incremental technique of border molding was performed for the mandibular arch using low fusing impression compound (Pinnacle tracing stick, DPI, Mumbai, India). The modelling wax was then removed and window was created in the flabby region. Tray adhesive was applied. A final impression with monophase (medium body) (Aquasil LV Monophase, Dentsply Caulk) addition silicone was made by lateral pressure technique. The master cast was then poured in type III dental stone and denture base was fabricated. No blanching or tissue rebound was observed when the denture bases were tried in the patient’s mouth.
The conventional method of facebow transfer, centric relation recording was done followed by protrusive record making and then mounting the casts. Lingualized occlusal scheme was selected with very minimal incisal guidance and characterization of the denture was done. Wax try in of both maxillary and mandibular dentures was done. The dentures were processed with heat-polymerizing denture base resin (DPI, India). Denture insertion was done and was assessed for any signs of tissue rebound. Pressure disclosing paste was used to further check for localized areas of tissue loading. Occlusal discrepancies were checked and eliminated by doing laboratory and clinical remount and the denture exhibited satisfactory retention and stability.
Patient was given post denture instructions and was recalled after 24 hours to check for any post-insertion complaints. No appreciable discomfort was noted and the patient was satisfied with the fit and function of the dentures. Patient was then scheduled for recall after 1 month and 3 months and was assessed for soft tissue health and occlusion.
Residual ridge is generally overlaid by 1.5-2mm of masticatory mucosa to provide adequate soft tissue support of the dentures as observed by Desjardins and Tolman. Flabby ridges are mainly composed of mucosal hyperplastic and loosely arranged fibrous connective tissue along with more dense collagenized connective tissue. Studies by Lynch and Allen, Carlsson, Xie et al., have reported approximately 5% of the edentate mandibles and 24% of the edentate maxillae to have flabby ridges. Support for complete dentures is significantly compromised if the flabby ridge has more than 2mm displacement under pressure. Retention, stability and support can be severely compromised by flabby tissues unless they have been managed appropriately.
Making an accurate impression of the edentulous ridge and the surrounding soft tissue is one of the most crucial steps in providing a stable, retentive and a functioning denture. Various special impression techniques have been proposed in the literature to manage flabby tissues with minimum amount of displacement. These techniques include muco-compressive, mucostatic and selective pressure techniques. Muco-compressive technique aims at compressing the loose flabby tissue to allow functional support from it by replicating the contour of the ridge during compression by occlusal forces. While, mucostatic technique aims to achieve support from the other firm areas of the arch and maximizes retention. There have been a lot of controversies about which technique to be used and it has been repeatedly reported that recording tissues at rest provide better stability.
Most techniques described in the literature are for anterior maxillary flabby ridges. Various techniques are described for maxillary fibrous arch such as Osborne technique (1964), Liddlelow technique (1964), Zafarullah Khan technique (1981), Watt and McGregor technique (1986), Hobkirk technique (1997). For mandibular arch generally Lateral window technique has been used. In the case presented above, the impression technique used for maxillary arch is in congruence with the technique presented by Bindhoo YA (2011)11 that made use of self-retaining custom trays with magnets. This magnetic retention ruled out finger pressure and provided an easy and stable orientation of special trays. The magnets also acted as tissue stops, avoiding over compression of displaceable tissue of crest. The vents in created in the maxillary tray helps in mechanical retention of the impression material and also creates a channel for excess material to flow out, thus giving an accurate impression.
While for mandibular arch, impression technique selected was lateral pressure technique. The displacement of tissues will occur in the techniques presented but that will be limited to 2-3 hours during mastication only. The tissues will remain in their natural static state for the rest of the time and the dentures will show uniform adaption thus providing good stability to the dentures. Also, the lingualized occlusal scheme that is selected will help to distribute the forces. A randomized prospective study by Matsumaru found that lingualized bilaterally balance occlusion was more efficient in terms of mastication and preservation of intercuspal position for patients with severe alveolar bone resorption.14 This will maintain tissue health and ensure good stability of the dentures as it is one of major problems while constructing complete dentures for flabby ridges.
An accurate impression is the first step towards providing a good retentive, stable and functioning complete denture. Presence of highly displaceable tissues presents a great difficulty in fabrication of a complete dentures. A self-retained magnetic tray for maxillary arch helps in recording the tissues in their most passive state by eliminating finger pressure. Lateral pressure technique for mandibular arch also helps in recording the tissues in their stable state.
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