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Overhanging interproximal silver amalgam restoration - Prevalence and side effects. (I.J.D.R., vol. 4, Jan., 1993)
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Overhanging interproximal silver amalgam restorations
- Prevalence and side-effects

Dr. Vimal Sikri, MDS, Senior Lecturer, Deptt. of Opervative Dentistry, Punjab Govt. Dental College and Hospital, Amritsar
Dr. Poonam Sikri, MDS, Senior Lecturer, Deptt. of Perio Dontology, Punjab Govt. Dental College and Hospital, Amritsar


ABSTRACT

This study was undertaken to find out the prevalence of overhanging class II silver amalgam restorations amongst patients visiting Pb. Govt. Dental College and Hospital, Amritsar and Govt. Dental College and Hospital, Patiala. Two parameters viz. the pocket depth and the extent of bone loss were evaluated to study the after effects of the overhanging restorations. The findings of this investigation showed the alarming prevalence of overhanging restorations (64.12%) and clerarly indicate the relationship of overhangs with periodontal diseases. Periodontal breakdown was more evident along with overhanging restorations as compared to unrestored contralateral teeth. The mean pocket depth in restored surfaces was 3.75 mm as compared to 3.46 mm in unrestored ones, showing 8.38% increase. The mean extent of bone loss in restored tooth surface was 1.64 mm as compared to 1.50mm in unrestored ones, showing an increase of 9.33%.


INTRODUCTION

The primary factor in the initiation and progress of inflammatory periodontal disease is undoubtedly the bacterial plaque. Accumulation of bacterial plaque around the tooth surface depends, leaving aside the systemic diseases, upon many local factors which individually or jointly initiate, enhance and supplement periodontal diseases. The most commonly encountered local factor causing periodontal disease in adults is the overhanging dental restorations. Overhanging dental restoration is defined as the extension of the restorative material beyond the confines of the prepared cavity. The consequences of overhanging restorations over the periodontium is so slow and painless that it never warrants the patients.

As early as in 1912, Black, quoted by Lang et al1, reported that the inflammation of periodontium is due to the favourable environment for plaque accumulation rather than to mechanical irritation of the overhanging restorations.

The relationship of periodontal diseases and overhanging restorations has been studied by various authors following different criteria. One or more parameters of periodontal diseases viz. pocket depth, extent of bone loss, gingival inflammation, gingival cervicular flow, etc. have been evaluated along the overhanging restorative surfaces by various authors.2,6 There was a consensus amongst them that the overhanging restoration is definite etiological factor in the progress of periodontal disease.

The prevalence studies presented in the literature showed wide variations. Gilmore and Sheiham (1971)5 in their study on 1976 civilians reported that 33% individuals had overhanging posterior restorations. Hakkarainen and Ainamo6 studied orthopantograms of 85 individuals and observed that 50% of all posterior restorations had overhangs. Claman et al3 observed 27.2% overhangs in their study on 826 patients using bitewing radiographs.

All the literature is inconclusive regarding the prevalence studies and also because of higher incidence of defective posterior restorations leading to breakdown of periodontium. This study was undertaken to know the prevalence of overhanging proximal silver amalgam restorations, their effect on periodontium as compared to the contralateral unrestored tooth and the management of such defects.

 

MATERIAL AND METHODS

Seven hundred and eighty six patients in the age group of 31-50 years having good oral hygiene were selected at random from the Outpatient Department of Punjab Govt. Dental College and Hospital, Amritsar and Govt. Dental College and Hospital, Amritsar.

All the selected patients had at least one CI.II silver amalgam restoration. The care was taken that the corresponding contralateral tooth was unrestored in all the selected patients.

The restored tooth of the patient was radiographed using Agfa and Minimax X-ray films following bisecting technique; equipments. The developed radiographs were observed over the viewbox by two postgraduate teachers. The radiographs with 'definite' overhangs (Overhangs above 0.25 mm, horizontal and/or vertical were taken as definite) were separated (Fig. I).

 

A

B



C

D



E

F


Fig. 1 : A, B, C, D:- Overhanging margins.
E and F      :- Sound margins.

 

Table 1

Prevalence of Overhanging Restorations Age-wise

S.No. Age in years Total sample No. of teeth
with overhang
Percentage
1. 31-35 186 117 62.90
2. 36-40 198 125 63.13
3. 41-45 212 140 66.03
4. 46-50 190 122 64.21
Total 786 504 64.12



Table 2

Pocket depths adjacent to Unrestored Teeth and

Restored Teeth with Overhangs in Millimeters

S.No. Age group
(years)
Total sample
n
Unrestored
teeth
Restored
teeth
Percentage
increase
1. 31-35 117 3.26 3.52 7.97
2. 36-40 125 3.41 3.76 10.26
3. 41-45 140 3.42 3.76 9.94
4. 46-50 122 3.78 3.96 4.76
Total 504 3.46 3.75 8.38



Table 3

Bone loss adjacent to Unrestored Teeth and

Restored Teeth with Overhangs in Millimeters

S.No. Age group
(years)
Total sample
n
Unrestored
teeth
Restored
teeth
Percentage
increase
1. 31-35 117 0.86 0.96 11.62
2. 36-40 125 1.29 1.42 10.07
3. 41-45 140 1.56 1.72 10.25
4. 46-50 122 2.32 2.46 6.03
Total 504 1.50 1.64 9



For convenience, the patients were divided into four age groups viz. 31-35, 36-40, 41-45 and 46-50; however, the sex differentiation was not considered.

The patients with definite overhangs were given appointment accordingly for examination of periodontium. On follow up examination, mostly within 48 hours, the contralateral homologous unrestored tooth of the patient was radiographed following the same criteria as was done for the restored tooth.

The extent of bone loss (the distance between CE junction to alveolar crest) was measured both in the restored tooth surface and also in the same surface of contralateral unrestored tooth using divider and vernier callipers by two teachers. The age group-wise readings were noted and compiled.

The pocket depth, both of the restored surface with overhanging restoration and the unrestored surface of the contralateral tooth was measured using callibrated periodontal probe, divider and callipers by the periodontologist. The age group-wise readings were noted and compiled.

The percentage increase in the extent of bone loss as well as the pocket depth around the tooth with overhangs were also calculated.

 

RESULTS

Prevalence of overhanging restorations age wise is presented in Table 1. Out of total 786 patients radiographed, 504 were found to have overhanging restorations (64.12%). In age wise grouping; in 31-35 years of age group, 117 patients showed overhangs out of 186 (62.90%); in 36-40 groups, 125 patients showed overhangs out of 198 (63.13%); in 41-45 age group, 140 patients showed overhangs out of 212 (66.03%) and in 46-50 years of age group, 122 showed overhangs out of 190 (64.21%).

Pocket depths adjacent to unrestored tooth surface and restored tooth surface with overhangs is presented in Table 2. The mean pocket depth around the restored tooth surface of all the 504 patients is 3.75 mm and around unrestored contralateral teeth, it is 3.46 mm; the mean increase in pocket depth is 0.29 mm (8.38%). In age wise grouping, the mean increase in 31-35 years of age is 0.26 mm (7.97%); in 36-40 years of age, it is 0.35 mm (10.26%); in 41-45 years of age, it is 0.34 mm (9.94%) and in 46-50 years of age, it is 0.18 mm (4.76%).

The bone loss adjacent to unrestored tooth surface and restored tooth surface with overhangs is presented in Table 3. The mean bone loss around the restored tooth is 1.64 mm while around unrestored contralateral tooth the mean is 1.50 mm in all the 504 patients. The mean increase of bone loss around the restored tooth is 0.14 mm (9.33%). In age wise grouping, the mean increase of bone loss in 31-35 years of age is 0.10 mm (11.62%); in 36-40 years, it is 0.13 mm (10.07%); in 41-45 years of age it is 0.16 mm (10.25%) and in 46-50 years of age it is 0.14 mm (6.03%).

 

DISCUSSION

Periodontal problems as a consequence of overhanging restorations are of concern to the dentists since long. It has been established that the overhanging restorations initiate and supplement the inflammatory periodontal diseases. The present study was conducted on 786 patients to find out the prevalence of overhanging restorations, their effect on periodontium and the criteria for management of such defects.

Only class II silver amalgam was considered because silver is the most commonly employed restorative material. Other restorative materials were not taken in this study to avoid material related factors.

The findings of the present investigations reported 64.12% of prevalence of overhanging restorations (Table I).

The prevalence reports would have been higher, if the minor overhangs were also considered. These findings are in concurrence with the findings of Than et al7 who have reported, in their clinical study on 240 extracted teeth, over 60% overhangs. Almost similar views have been expressed by Hakkarainen and Ainamo6, who studied orthopantomograph of 85 individuals and reported that 50% of all posterior restorations had overhangs.

Claman et al3, however, reported 27.2% prevalence of overhanging restorations. They studied bitewing radiographs of 826 patients and the overhangs above 0.5mm were considered. The difference with the present study could be because the minimum size of the overhang considered was 0.5mm. Gilmore and Sheihan5, have also reported contrary prevalence reports. They could report 33% overhangs when bitewing radiographs of 1976 civilians were viewed.

The extent of periodontal breakdown was evaluated by two parameters viz. pocket depth and bone loss. Different authors have studied different parameters; for example, Lang et al1 evaluated the subgingival microflora; Eid8 studied the cervicular fluid flow and Than et al7 evaluated the attachment loss.

The mean increase of pocket depth with restored surface as compared to contralateral unrestored surfaces was 0.29 mm (8.38%). These findings are in concurrence with the findings of Claman et al3 who have reported 0.20 mm to 0.27 mm increase in pocket depth with the overhanging restorative surfaces. Other studies as quoted by Brunsvold9 have also reported 0.20 mm to 0.42 mm increase in pocket depth with overhanging restorations.

The mean increase in the extent of bone loss around teeth with overhanging restorations as compared to contralateral unrestored teeth was 0.14 mm (9.33%). These findings are similar to the findings of Eid8, who has reported 0.16 mm increase; Gilmore and Sheihan5, 0.22 mm increase and Jeffcoat and Howell10, 6-12% increase. However, Hakkarainen and Ainamo6, have reported 0.87 mm increase which is much more as compared to the present study. This might be because Hakkarainen and Ainamo6, have also considered the age of the overhang and observed that the magnitude of bone loss increased with the increasing severity of periodontal diseases. In summary the findings of the present study defintiely correlate periodontal diseases with the overhanging restoration.

The common saying 'Prevention is better than cure' is to be followed by every dentist to avoid occurrence of overhanging restoration. Any restoration with overhang, if detected in routine X-ray examination, must be contoured immediately. Different devices have been utilized to reshape the overhanging restorations. The common among these are the diamond points, curretes and even ultrasonic instruments. Abrasive discs, finishing burs and the finishing strips can also be utilized to contour the proximal restorations.

Vale and Caffase11, have mentioned about the EVA system but cautioned their use, since they might abrade the adjacent tooth. The overhanging restorations are best removed during the flap surgery. These can be reshaped. with scalers and finished with abrasive discs.

The signficant beneficial results have been reported after removal of the overhangs.

 

REFERENCES

  1. Lang, N.P., Keil, R.A. and Anderhalden, K. : Clinical and microbiological effects of subgingival restorations with overhanging or clinically perfect margins. J. Clin. Period. : 10, 563, 1983.
  2. Chen, J.J., Burch, J.G., Beck, F.M. and Horton, J.E. : Periodontal attachment loss associated with proximal tooth restoration. J. Prosth. Dent. : 57, 416, 1987.
  3. Claman, L.J., Kuidis, P.J. and Burch, J.G. : Proximal tooth surface quality and periodontal probing depth. J.A.D.A. : 113, 890, 1986.
  4. Gher, M.E. and Vernino, A.R. : Root morphology - Clinical significance in pathogenesis and treatment of periodontal diseases. J.A.D.A. : 101, 627, 1980.
  5. Gilmore, N. and Sheihan, A. : Overhanging dental restorations and periodontal disease. J. Prosth. Dent. : 42, 8, 1971.
  6. Hakkarainen, K. and Ainamo, J. : Influence of overhanging posterior tooth restoration on alveolar bone height in adults. J. Clin. Period. : 7, 114, 1980.
  7. Than, A., Duguid, R. and Mckendrick, A. : Relationship between restorations and the level of the periodontal attachment. J. Clin. Period. : 9, 193, 1982.
  8. Eid, M. : Relationship between overhanging amalgam restoration and periodontal disease. Quint. Int. : 18, 775, 1987.
  9. Brunsvold, M.A. and Lane, J.J. : The prevalence of overhanging dental restorations and their relationship to periodontal diseases. J. Clin. Period. : 17, 67, 1990.
  10. Jeffocoat, M.K. and Howell, T.M. : Alveolar bone destruction due to overhanging amalgam in periodontal diseases. J. Prosth. Dent. : 51, 599, 1980.
  11. Vale, J.D.F. and Caffese, R.G. : Removal of amalgam overhangs. J. Prosth. Dent. : 50, 245, 1979.
 

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