Longitudinal Study of Magnetic attachments

 –Investigation of Probing Depth on Abutment Teeth Part.3-

 

R. Ito , M. Miwata , K. Hoshiai , Y. Tanaka , T. Ishigami¹⁾, K. Ishibasi²⁾, E. Bando³⁾, H. Sasaki⁴⁾, H. Mizutani⁵⁾ and T. Hosoi⁶⁾

Department of Removable Prosthodontics , School of Dentistry, Aichi-Gakuin University

¹Department of Partial Denture Prosthodontics , Nihon University School of Dentistry 

²Department of Fixed Prosthodontics , School of Dentistry , Iwate Medical University　

³Department of Fixed Prosthodontics , Institute of Health Biosciences Graduate School The University of Tokushima 　

⁴Sasaki Dental Clinic　

⁵Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University 　

⁶Department of Removable Prosthodontics, Tsurumi University School of Dental Medicine

 

Introduction

At present, magnetic attachments have been applied clinically in various treatment plans. It’s useful to carry out postoperative investigations and to confirm results, as it shows the criterion of the clinical application. ¹⁾  Thus , magnetic attachments can be used safely.

Prospective investigation of magnetic attachments has been carried out since 2003 at the Japanese Society of Magnetic Applications in Dentistry.（JSMAD）

Comparison by condition of abutment teeth was reported earlier. ²⁾ This time, the comparison by tooth classification is reported.

Methods

 The transition in probing depth (PD) of the abutment teeth was measured and the changes in the conditions of periodontal tissue were evaluated.

Immediately after cementation, oral conditions were recorded by use of an original questionnaire, and PD were measured by the 6 points method.

Patients were recalled after 5 years and PD was measured. 5 departments participated in earlier study. In this study, 7 departments participated .

Results

 

Fig.1 shows the transition of PD by Kennedy’s classification. Significant difference were found in Class�U and �V．

Fig.2 shows the transition of PD by Eichner’s classification. The number of abutment teeth of class A is only one. So statistical analysis could not be used.

Significant difference were found in Class B.

Table.1 shows the position between abutment teeth and defect.

The white circle mean abutment tooth, the black circle mean another tooth and the black line mean missing. Abutment teeth were classified into 4 types.

(1)        Abutment teeth adjacent to distal extension defect.

(2)        Abutment teeth adjacent to intermediary defect.

(3)        Abutment teeth adjacent to distal extension and intermediary defect.

(4)        Abutment teeth adjacent to no defect.

In addition,(1) and (2) were further classified into two types.

Type one is abutment teeth adjacent to one sided defect and type two is adjacent to both sided defect. The code of (1)-1 is α and the number of teeth is

21. There is no abutment tooth adjacent to both sided distal extension defect. The code of 2-(1) is β and the number of teeth is 20. The code of 2-(2) is γ　and the number of teeth is 11. The code of 3 is δ and the number of teeth is 21. The number of abutment teeth adjacent to no defect is few and so statistical analysis had not been used.

 

Fig. 3 shows the transition of PD by classification of the position of abutment teeth. Significant difference were found in β.

Table.2 shows the result of the transition by tooth classification and the position of abutment teeth. Significant difference were found between in Kennedy class�U,�V, Eichner B and abutment teeth adjacent to one sided intermediary defect.

Fig.4 shows the details of treatment and troubles. The types of magnetic attachments are Magfit (48 teeth), GIGAUS (7 teeth), Hycolex (14 teeth), Hyper Slim (6 teeth).

 The types of metal are gold-silver-palladium-alloy (64 teeth) platinum-gold-alloy (7 teeth) and unknown (4 teeth). The materials of cementation are resin adhesive (62 teeth), glass ionomer (8 teeth) and unknown (5 teeth). The troubles of dentures are reproduction (4 cases), omission of magnet from the dentures (6 cases), repair (2 cases) and broken of magnet (1 case).  

Discussion

Significant difference were found between initial PD and PD 5 years later in Kennedy class�U,�V、Eichner B and abutment teeth adjacent to one sided intermediary defect. Kennedy class �U that mean unilateral distal extension defect, Kennedy class �V that mean unilateral intermediary defect, Eichner B that lose one of occlusal support and abutment teeth adjoining one-sided intermediary defect. This result corresponds with a retrospective cohort study that the survival rate of the abutment teeth that have many occlusal support is low. ³⁾The reason is if the denture has many occlusal supports, large occlusal force are added to the abutment teeth.   

Conclusion

The result of prospective observation of magnetic attachments from the point of the transition of PD for 5 years is below.

 

・ PD of abutment teeth of unilateral distal extension defect and unilateral intermediary defect were increased over 5 years period.

・ PD of abutment teeth that lose one of 4 occlusal support were increased over 5 years.

・ PD of abutment teeth adjoining one-sided intermediary defect were increased over 5 years.

 

 

References

  Literature references should be listed at the end of the paper in the same order that they appear in the text, and in accordance with the following examples.

1.         K. Hoshiai, Y. Tanaka, M. Kawakita, W. Fujinami, K. Wakayama, Y. Imaizumi, T. Matumoto and M. Sakane: Longitudinal Study on Metal Plate Denture with Magnetic Attachments-Part 4, J J Mag Dent, 13(2), 26-29, 2004.

2.         R. Ito, K. Hoshiai, Y. Tanaka, T. Ishigami, K. Ishibashi, E. Bando and H, Sasaki: Longitudinal Study of Magnetic Attachments -Investigation of Probing Depth on Abutment teeth-, J J Mag Dent, 19(2), 35-39, 2010.

3.         R. Ito, K. Hoshiai, N. Hasegawa, N. Muraji, T. Kawaguchi, K. Noda, K. Watanabe and Y. Tanaka

: Longitudinal Study on Metal Plate Denture with Magnetic Attachments, J J Mag Dent, 18(2), 8-14, 2009.