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Summary

Objectives: To evaluate fatigue of stud (ERA Overdenture (orange and white), Locator Root (pink) and OP anchor # 4) and magnetic (Magfit EX600W) attachments by measuring maximum retentive force. To compare retentive force of overdenture attachments after their reach stable retention. To determine minimum number of cycles required to reach stable retention.

Material and methods: Three specimens of each type of attachment were used. Micromaterial testing machine (MMT-250NB-10, Shimadzu Co., Tokyo, Japan) with a sensor interface PCD-320 and software package PCD-30A (Kyowa Electronic Instruments Co., Tokyo, Japan) was used to performe 2000 insertion-removal cycles with 50 mm/min cross head speed. Maximum retentive force was measured initially and after each 40 cycles. Statistical analysis: paired-samples t-test, one-way ANOVA and Scheffe post-hoc tests (P<0.05).

Results: Before and after fatigue simulation statistically significant differences existed among the five types of attachments. Decrease of retention was characteristic for all attachments except OP. After fatigue LRP was most retentive. Magnetic attachments preserved maximum amount of retention measured at the baseline (98%). EO and EW attachments have preserved only 25% and 37% of initial retention respectively.

Conclusions: Due to fatigue overdenture attachments gradually loose their retention. Stud attachments are more susceptible to fatigue than magnets. Eight hundred cycles are required to achieve relatively stable retention of overdenture attachments.

Key words: overdenture, studs, magnets, retention, fatigue.

Received: 20 10 2005

Accepted for publishing: 30 11 2005

¹Center of Prosthodontics, Institute of Odontology, Faculty of Medicine, Vilnius University, Vilnius, Lithuania

²Department of Removable Prosthodontics, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan

³Department of Advanced Biomaterials, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan

Vygandas Rutkunas¹ - D.D.S., Prosthodontist

Hiroshi Mizutani² - D.D.S., PhD., Associate Professor

Hidekazu Takahashi³ - D.D.S., PhD., Associate Professor, Chair

Address correspondence to Vygandas Rutkunas: Center of Prosthodontics, Institute of Odontology, Faculty of Medicine, Vilnius University, Zalgirio str. 115, Room #231, 08217 Vilnius, Lithuania.

E-mail: vygandasr@gmail.com



	Baltic Dental and Maxillofacial Journal

December, 2005, Vol. 7, No. 4 CONTENTS SCIENTIFIC ARTICLES Dental restorations quality in Lithuanian adolescents 103 - 109 Treatment of parotid gland tumors in Latvian Oncological Center 110 - 114 Evaluation of stable retentive properties of overdenture attachments 115 - 120 The influence of microvascular complications caused by diabetes mellitus on the inflammatory pathology of periodontal tissues 121 - 124 Influence of premolar extractions on tooth size discrepancy. Part one: Analysis of Bolton index 125 - 127 Implants for orthodontic anchorage. Meta-analysis 128 - 132 © 2005 Stomatologija		Stomatologija 2005; 7 (4): 115-20 293 KB Evaluation of stable retentive properties of overdenture attachments Vygandas Rutkunas, Hiroshi Mizutani, Hidekazu Takahashi Summary Objectives: To evaluate fatigue of stud (ERA Overdenture (orange and white), Locator Root (pink) and OP anchor # 4) and magnetic (Magfit EX600W) attachments by measuring maximum retentive force. To compare retentive force of overdenture attachments after their reach stable retention. To determine minimum number of cycles required to reach stable retention. Material and methods: Three specimens of each type of attachment were used. Micromaterial testing machine (MMT-250NB-10, Shimadzu Co., Tokyo, Japan) with a sensor interface PCD-320 and software package PCD-30A (Kyowa Electronic Instruments Co., Tokyo, Japan) was used to performe 2000 insertion-removal cycles with 50 mm/min cross head speed. Maximum retentive force was measured initially and after each 40 cycles. Statistical analysis: paired-samples t-test, one-way ANOVA and Scheffe post-hoc tests (P<0.05). Results: Before and after fatigue simulation statistically significant differences existed among the five types of attachments. Decrease of retention was characteristic for all attachments except OP. After fatigue LRP was most retentive. Magnetic attachments preserved maximum amount of retention measured at the baseline (98%). EO and EW attachments have preserved only 25% and 37% of initial retention respectively. Conclusions: Due to fatigue overdenture attachments gradually loose their retention. Stud attachments are more susceptible to fatigue than magnets. Eight hundred cycles are required to achieve relatively stable retention of overdenture attachments. Key words: overdenture, studs, magnets, retention, fatigue. Received: 20 10 2005 Accepted for publishing: 30 11 2005 ¹Center of Prosthodontics, Institute of Odontology, Faculty of Medicine, Vilnius University, Vilnius, Lithuania ²Department of Removable Prosthodontics, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan ³Department of Advanced Biomaterials, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan Vygandas Rutkunas¹ - D.D.S., Prosthodontist Hiroshi Mizutani² - D.D.S., PhD., Associate Professor Hidekazu Takahashi³ - D.D.S., PhD., Associate Professor, Chair Address correspondence to Vygandas Rutkunas: Center of Prosthodontics, Institute of Odontology, Faculty of Medicine, Vilnius University, Zalgirio str. 115, Room #231, 08217 Vilnius, Lithuania. E-mail: vygandasr@gmail.com