• The Journal of Korean Academy of Prosthodontics
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• v.21 no.1
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• pp.59-66
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• 1983

Distal extension partial dentures are supported by both the relatively rigid teeth and the resilient mucosa. So impression techniques of residual alveolar ridge in case of distal extension partial denture have particular importance in order to broad distribution of the masticatory force. McLean recognized the need for recording the tissues supporting distal extension partial denture base in functional form to equalize the resilient and non-resilient support, and this was called functional impression. Many investigators proposed various techniques of the functional impression for a distal extension partial denture, but only a little studies were performed about displacement of soft tissue under distal extension partial denture base. The purpose of this study is to investigate the amount of vertical displacement of the soft tissue under distal extension partial denture base by different functional impression techniques. Impression techniques used were Z.O.P. Impression, Selective Tissue Placement Impression, Functional Relining Impression. Measurement of the vertical displacement of soft tissue were made with Depth Gauge and Measuring Platform. A Anatomic Impression was used as a control. The results were tested statistically using 3 way ANOVA and Scheffe test. The followings were the results obtained from this study. 1. The greatest amount of soft tissue displacement was observed in the center of the retromolar pad. 2. No significant differences were found between the crest of alveolar ridge and the buccal shelf area. 3. The greatest soft tissue displacement was observed in Functional Relining Impression using Iowa wax, and the least displacement was observed in Selective Tissue Placement Impression using murcaptan rubber base. 4. No significant differences were found between finger pressure and biting pressure in Z.O.P. Impression, but greater displacement was observed by biting pressure than finger pressure in Functional Reling Impression.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.2
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• pp.130-136
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• 2020

Fabrication of complete denture with suction mechanism was introduced to enhance the retention and stability of denture by sealing around the denture border by forming negative pressure on the inner side of denture base during functional movement such as swallowing or masticating. Mandibular suction dentures reduce denture dislodging force during opening by taking preliminary impression without pressure on retromolar pad area in rest position. In this case, fabrication of complete denture using suction mechanism for an edentulous patient with severe alveolar bone resorption allowed us to clinically enhance retention and stability of denture and improve satisfaction of patient.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.1
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• pp.341-355
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• 1999

Squamous cell carcinoma is the most common type of oral cancer and odontogenic myxoma is relatively uncommon benign tumor of mesenchymal origin. There are, to our knowledge, no prior reports of simultaneously occurring squamous cell carcinoma and odontogenic myxoma of the jaw bones. In this case, at first, the plain films and computed tomograms revealed a large expansile multilocular radiolucent lesion on left mandible and marked expansion of cortical plate. In addition this radiograms revealed also infiltrative bony destruction of anterior and medial border of ascending ramus of left mandible and alveolar bone of left maxilla, floating teeth on left lower molar area and metastatic enlargement of left submandibular, jugular digastric and spinal accessory lymphnodes. Magnetic resonance imaging of this patient revealed infiltrative growth of tumor on alveolar bone of left maxilla, left retromolar fat pad. left masseter and left medial pterygoid muscle. Intraoral presurgical biopsy presented typical features of squamous cell carcinoma. After chemotherapy with radiation therapy during 6 months. this central lesion was diagnosed as odontogenic myxoma by the postsurgical biopsy. After 3 months, this patient presented multiple metastatic signs at lumbar spines, rib and liver. Consequently, our case is simultaneous occurrence of squamous cell carcinoma and odontogenic myxoma.

• The Journal of Advanced Prosthodontics
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• v.16 no.3
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• pp.139-150
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• 2024

PURPOSE. The purpose of this diagnostic study was to assess the accuracy and time efficiency of a digital method to draw the denture foundation extension outline on preliminary casts compared with the conventional technique. MATERIALS AND METHODS. A total of 28 preliminary edentulous casts with no anatomical landmarks were digitized using a laboratory scanner. The outlining of the entire basal seat of the denture was performed on preliminary casts and digitized. Casts with no extension outline were digitized and outlines were drawn using software (DWOS, Straumann). The accuracy of the extension outlined between both techniques was evaluated in the software (GOM Inspect; GOM GmbH) by file superimposition. Specificity and sensitivity tests were applied to measure accuracy. The paired t-test (95% CI) was used to compare the mean total area and the working time. RESULTS. The accuracy ranged from 0.57 to 0.92. The buccal and labial frenulum showed a lower value in the maxilla (0.57); while the area between the retromolar pad and buccal frenulum (0.64) showed a lower score in the mandible. The maxillary denture foundation and the working time for both arches were significantly longer for the digital method (P < .001). CONCLUSION. The denture foundation extension outline exhibited a sufficiently excellent accuracy for the digital method, except for the maxillary anterior region. However, the digital method required a longer working time.

• Journal of Periodontal and Implant Science
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• v.32 no.1
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• pp.13-23
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• 2002

The ultimate goal of periodontal therapy is directed to arresting the progression of the disease, and regenerating the fibrous attachment. In order to achieve such treatment aim, the plaque and calculus must be eliminated and the physiological conditions of the root surface must be changed to facilitate the attachment and migration of the new fibroblasts, The method of changing the proper root surface conditions to promote the healing of periodontal tissue involves mechanical procedures, such as scaling and root planing, and chemical procedures such as tetracycline-HCl. However, the formation of a long junctional epithelium was most frequently observed type of healing. Thus, the aim of this study was to examine in vitro the influence of surface conditioning of dentin by TC-HCl on human gingival epithelial cell attachment. Human gingival epithelial cells were obtained from healthy retromolar pad area(under the age 23 years). Seventy two teeth extracted from severe periodontitis were used as study material. To evaluate the epithelial cell attachment to dentin, the prepared specimen was divided to four groups. For the control group, only scaling and root planing were carried out, and for the test group, 1 to 3, the concentration of the TC-HCl was 50, 125 and 250mg/ml respectively. After cell cultivation time of 1-, 3-. 24 hour, for the indirect quantitative assessment of gingival epithelial cell attached to dentin sample, the absorbance of epithelial cell unattached to dentin was measured. The results were as follows; 1. There was no statistically significant difference between scaling and root planing group and TC-HCl 50mg/ml 125mg/ml and 250mg/ml group about absorbance of unattached epithelial cell to dentin sample(p>0.5). 2. As time passes, the absorbance of unattached gingival epithelial cell to dentin sample was decreased statistically significant(p<0.05). 3. There was no statistically significant difference among the TC-HCl group(p>0.05) We concluded that there was similar effect on gingival epithelial cell attachment between TC-HCl conditioning on root surface and only scaling and root planing treatment

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.1
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• pp.18-25
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• 2023

We present the case of a 65-year-old man with maxillary and mandibular complete dentures prepared using neutral zone technique after undergoing mandibulotomy due to tonsil cancer 10 years ago. The patient had a short edentulous period; hence, there was minimal absorption of the alveolar ridge and no abnormality in the motor function of the tongue. However, the retromolar pad was located inside the hamular notch, and the posterior alveolar ridge was relatively turned inward. If the artificial teeth would have been aligned conventionally, the functional space of the tongue would have been invaded, which would have moved the tongue posteriorly thereby reducing the stability of the denture. Therefore, applying the concept of the neutral zone can be a good reference point in such cases. The neutral zone was registered using tissue conditioner, and tooth alignment was performed by making a silicone putty index. The biggest advantage of using neutral zone concept is denture stability. In this case, the neutral zone technique was applied to obtain the lingual alignment limit of the posterior teeth to avoid invasion of the tongue space by the left posterior part of the mandible. Particularly, in case of a patient in which denture stability is difficult to obtain due to absorption of the alveolar ridge, it is believed that better results can be obtained using neutral zone technique.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.1
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• pp.18-26
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• 2021

Purpose: Generally, patients are noticed to store denture in water when removed from the mouth. However, few studies have reported the advantage of volumetric change in underwater storage over dry storage. To be a reference in defining the proper denture storage method, this study aims to evaluate the volumetric change and dimensional deformation in case of underwater and dry storage. Materials and methods: Definitive casts were scanned by a model scanner, and denture bases were designed with computer-aided design (CAD) software. Twelve denture bases (upper 6, lower 6) were printed with 3D printer. Printed denture bases were invested and flasked with heat-curing method. 6 upper and 6 lower dentures were divided into group A and B, and each group contains 3 upper and 3 lower dentures. Group A was stored dry at room temperature, group B was stored underwater. Group B was scanned at every 24 hours for 28 days and scanned data was saved as stereolithography (SLA) file. These SLA files were analyzed to measure the difference in volumetric change of a month and Kruskal-Wallis test were used for statistical analysis. Best-fit algorithm was used to overlap and 3-dimensional color-coded map was used to observe the changing pattern of impression surface. Results: No significant difference was found in volumetric changes regardless of the storage methods. In dry-stored denture base, significant changes were found in the palate of upper jaw and posterior lingual border of lower jaw in direction away from the underlying tissue, maxillary tuberosity of upper jaw and retromolar pad area of lower jaw in direction towards the underlying tissue. Conclusion: Storing the denture underwater shows less volumetric change of impression surface than storing in the dry air.