Frequency and Severity of Post-operative Pain in Recently Placed Amalgam Restorations

Frequency and Severity of Post-operative Pain in Recently Placed Amalgam Restorations
Fazal ur Rehman Qazi1 , Shahbaz Ahmed Jat2 , Arshad Hasan3 , YawarAli Abidi4

1 Assistant Professor, Department of Operative Dentistry, Dr Ishrat-ul-EbadKhan Institute ofOralHealthSciences
2 Assistant Professor, Department of Operative Dentistry Dr Ishrat-ul-EbadKhan Institute ofOralHealthSciences
3 Assocaite Professor and Head Department of Operative Dentistry,DowDentalCollege.
4 Assocciate Professor and Head Department of Operative Dentistry, Dr Ishrat-ul-Ebad Khan Institute of Oral Health Sciences.

How to CITE:

Qazi FR, Jat SA,HasanA, AbidiYA Frequency and severity of post-operative pain in recently placed amalgamrestorations. J Pak DentAssoc .2012 21(03) 136 140


The amalgam restorations are associated with postoperative sensitivity which reduces with the passage of time. The objective of this study was to find out the severity of postoperative pain in routinely placed amalgamrestorations.


This yearlong study was conducted at Department of Operative Dentistry, Fatima Jinnah Dental College. It was a cross-sectional study based on one hundred patient’s complaint about pain that they experienced following placement of a restoration of a moderate Class I or II carious lesion. This information was collected by 3 questionnaires, consisting of day 1, 4, and 7 post treatment records.Collected datawas analyzedwith SPSS forwindows version 17 using the Friedman pair test at a ignificance level of 5%.


Forty four out of hundred patients reported postoperative sensitivity and pain on day 1. This number reduced to only nine patients at day 7, havingminor sensitivity,whichwas verymild and reducing in nature.


Postoperative sensitivity in recently placed amalgam restoration subsides in majority of patients after 1week.


Postoperative pain, amalgam, posterior restorations.


Dental amalgam is one of the oldest, durable, safest, and least expensive materials for restoration. It is commonly used in small to moderate sized posterior cavities where moisture control is problematic and more costly alternatives are not affordable by the patient. However, amalgam dental restorative material has certain disadvantages such as non adhesion to tooth structure and initial micro leakage.

This micro leakage in the tooth/amalgam interface causes pulpal pain as explained by hydro-dynamic theory. Newly placed amalgam restoration is subjected to corrosion, and the products of this corrosion are deposited in the gap between tooth and restoration, resulting in reduced micro leakage. This reaction was reported by Kelsey 1988; Panneton 1988 and Eley 1997. This reaction is slow to start with and may take upto a few months before the symptoms improve. In order to avoid the post-operative sensitivity, varnishes, liners and bases have been advocated for this interim period. Various varnishes, calcium hydroxide and glass ionomer cements have all been indicated. Recently, there is a trend towards the use of bonding agents and amalgam bonding to address the sensitivity issue. Latest addition to this list is the use of some sort of cavity disinfection before restoration placement with a belief that reduced bacterial countwill result in less post-operative sensitivity.

The issue of postoperative sensitivity of amalgam restorations has been reported previouslywith contrasting results. One study reported sensitivity in majority of subjects. Another study reported sensitivity in quarter of the patients. These and similar studies are from various parts of the world and there is a lack of local data on this topic. Therefore, the objective of this study was to determine the severity of postoperative pain, following routine placement of dental amalgam restorations in local population.


This cross-sectional survey was conducted at Fatima Jinnah Dental College. One hundred patients who received restoration at the department of operative dentistry, over a period of one year were included in the study. All the restorations were performed by single operator. Vital teeth with moderate sized (determined by pre-operative radiograph) class 1 and 2 cavities with no history of pain were included. Any teeth with doubtful pulp history or deep restorations (within inner third of dentin) were excluded. Selected patients were asked to sign an informed consent. Post-operatively patients were asked about the sensitivity experienced, by completing 3 supplied questionnaires for days 1, 4, and 7 post treatment (Fig no.1).

The questionnaires comprised of four questions and used the visual analogue scale(VAS) as response. The VAS comprised of a 5 inch line graduated at each inchwith the descriptors “no pain” and “severe pain” underneath the line, at the extreme left and right ends respectively. Patients experiencing severe pain tick marked at the extreme right i.e. pain score 5 and those with no pain on the extreme left i.e. pain score 1. Thosewith pain less than severe, marked at the point along the line which best described the pain. The pain score for all four questions was added and taken as the pain score for that day. A collective final score of 4(sum of lowest score from all 4 questions) indicated no pain, 5-8 indicated minor pain, 9- 12 indicated mild pain, 13-15 indicated moderate pain, where as a collective score of 16-20 indicated severe pain. The recorded datawas analyzedwith S.P.S.S. forwindows version 17. Final scores (sum of pain scores for each of 4 questions) were recorded for all 100 patients for day 1, 4 and 7. Friedman pair test was used to compare final pain scores of day 1, 4 and 7 at a significance level of5%.


Atotal of 100 patients were included in this study.All of the patients were available for the evaluation at followup for days 1, 4 and 7. The complete follow-up of the patients was possible because most of the patients had more than one cavity and were recalled in such a manner that they became available for the required days. Out of hundred patients 66% were without pain on day1, This percentage increased to 81% on day 4 and 91% of the patientswere free of pain on day 7 (Table 1).

Eleven patients out of 100 showed collective mean score of 5 on day 1 and seven patients had a mean score of 6. Another seven had pain score of 7, whereas the other eight reported pain score of 8. Only one patient had a pain score of 9 which was maximum for all recorded scores on day 1(Table: 1). On day 4, pain score of twelve patients was recorded as 5,whereas six patients showed a pain score of 6,while only one patient showed a pain score of 7. None of the remaining patients showed pain score more than 7 (Table: 1). On day 7, Eight patients out of 100 showed pain score of 5 and only one patient had a pain score of 6. None of the remaining patients showed more than 6 pain score. (Table: 1). The no pain descriptive (Final pain score 4) was found in 66 patients on day 1 and in 81 on day 4 and 91 on day 7. Similarlyminor pain (score 5, 6 and 7) was noted for twenty five patients on day one, nineteen on day four and nine on day 7.Mild pain score (8 and 9) was recorded for 9 patients on day 1, 0 on day 4 and 7. The collective mean pain score for day1 was 4.83 (SD 1.37) for days 4 and 7 was 4.27 (SD 0.62) and 4.10 (SD 0.33) respectively, as shown inTable no. 2. The difference between the collectivemean pain score between day1 and 4, day 4 and 7 and day 1 and 7was found to be statistically significant (Pvalue < 0.05).


The prevalence and severity of postoperative pain vary substantially as reported by various studies. However, it is difficult to generalize these results due to differences in inclusion/exclusion criteria and methodology. Our study revealed thatmajority of patients was symptom free, while some patients reported minor to mild postoperative pain and sensitivity. Similar experience was reported by other studies. However, one study reported sensitivity in majority of patients after first week. Previously researchers found postoperative pain after dental restorative treatment vary frequently . It has also been reported that some cases of dentin hypersensitivity induced by exposure of dentin may remain after the tubules are effectively closed. This may be due to the pulpal inflammation and consequent sensitization of the interdental nerves17. In another study,55 % of patients reported mild to moderate sensitivity to cold after dental restorations that included use of conventional liners and Glass ionomer cement and the cavities were not etched to remove the smear layer. Since the liner placement does not make much difference in moderate sized cavities , the bacterial infection might be the reason for sensitivity found in 44 % patients . In another study, Brannstrom described the relationship between pulpal hydrodynamics and thermal sensitivity and concluded that two sources of bacterial contamination were responsible for the infection: bacteria in the smear layerand the ingress of bacteria viamicro-leakage In our study, the pain score gradually decreased over the period of one week. The collective mean score of the pain was as low as 4.83 on day 1. It reduced to 4.27 and 4.10 on days 4 and 7 respectively. In other study postoperative pain and sensitivity was also found gradually reducing right from the first day being minimal at the end of first week . Only 2 patients found it necessary to take an analgesic, which was prescribed to patient on need. The mean score is more useful to practicing dentists. The 0-5 scale can easily be transformed to amore easily understood descriptive scale. The collectivemean pain scores are divided into following groups as: 4, 5-8, 9-12, 13-15 and 16.1-20.They can be converted to word descriptive scores as: No pain, Minor, Mild,Moderate and Severe respectively. Thus, the result according to the new scale reveals that the pain on day1 comes under Minor pain. The pain continued to reduce except with hot stimuli on day 7, when most of the pain subsided. Historically, postoperative pain associated with temperature was considered a thermal conduction problem. More recently, pulpal hydrodynamics has been used to explain this sensitivity . Thermal sensitivity seems to be themost persistent problemin our study since the data does not reflect significant decrease in pain at the 4- and 7- day questionnaires.

As shown in some studies the use of adhesive liner under amalgam restorations is reputed to eliminate thermal sensitivity, but not in every case. The explanation may be that the results are product specific .Other studies have demonstrated that etching dentin removes the smear layer and dentinal adhesive liners reduce micro-leakage under amalgam restorations . The dentin etching and the placement of dentinal adhesive liners are well-tolerated by the pulp . In another study one liner ystem was not found superior to other liners and bases. However, Balanko in 1992 found that the bonded silver amalgam restorations, have excellent retention, does not require pins, strengthen remaining tooth structure and eliminate the likelihood of cusp fracture and postoperative sensitivity These facts make it difficult to decide whether the increased time and expense of placement of resin liner under every amalgam restorations is really justified by increased benefit to the patient. Furthermore the uncertainty about the long term clinical performance of these bonded amalgams is problematic .Only a short term data, based on clinical observations of bonded amalgamis available at present. However, it is worthwhile to think that dentinal adhesive liners can be placed under amalgam restorations without bases, to avoid undue thermal sensitivity.


On the basis of the results obtained in our study we conclude:
1: 34% of surveyed patients showed postoperative pain and sensitivity after restoration of moderate class I and II lesions.
2: The reported pain was typically minor and for short duration.
3: After 24 hours, sensitivity was reported to decrease, and by the end of the 1st week, 90% patients recovered from pain.
We did not take into account the effect of age on pain scores. The volume of dental pulp regresses with age and this can have a reducing effect on pain scores.
The data was limited to small to moderate cavities. The effect of cavity depth on postoperative pain could not be studied.
We used readily available liners and bases in our study.We did not group our patients according to the type of liner used.
We recommend studying the effect of different liners, cavities of varying depth including deep cavities, age and gender in future studies of post-operative pain after placement of amalgam restorations in future studies.
Conflict of interest:
We report no conflict of interest.


1. Brownawell AM, Berent S, Brent RL, Bruckner JV, Doull J, Gershwin EM The potential
adverse health effects of dental amalgam. Toxicol Rev. 2005; 24:1-10.
2. Grover, P., Hollinger, J., Lorton, L. A review of the incidence of pain after an operative treatment
visit Part I. JProsthetDent 1984;51: 224-225.
3. Johnson, G., Gordon, G., Bales, D. Postoperative sensitivity associated with posterior composite
and amalgam restorations. Oper Dent 1988; 13: 66-73.
4. Torstenson B, Brännström M. Pulpal response to restoration of deep cavities with high-copper amalgam.SwedDent J. 1992;16 :93-99.
5. Rashid A. Bonded amalgam restorations. Fauji FoundHealth J.Mar 2001; 2-1: 54.
6. Ben-Amar A, Cardash HS and Judes H, The sealing of the tooth/amalgam interface by corrosion
products, JOral Rehabil 1995; 22:101-104.
7. Kelsey WP 3rd, Panneton MJ. A comparison of amalgam microleakage between a copal varnish and two resin-compatible cavity varnishes. Quintessence Int. 1988;19:895-898.
8. Eley, B.M. The future of dental amalgam: a review of the literature. Part1: dental amalgam structure and corrosion. BrDent J. 1997; 182:247-249.
9. Lyon, H., Michell, R. Pulp protection and basing procedures: A survey of dental schools. Oper Dent
1983; 8: 106-111.
10. Andrews, J., Hembree, J. Marginal leakage of amalgam alloys with high content of copper: A
laboratory study.OperDent 1980; 5: 7-10.
11. Ziskind, D., Venezia, E., Kreisman, I., Mass, E. Amalgam type, adhesive system, and storage periods as influencing factors on microleakage of amalgam restorations. J Prosthet Dent 2003; 90: 255-260.
12. Schwartz, R., Conn, L., Haveman, C. Clinical evaluation of two desensitising agents for use under
Class 5 silver amalgam restorations. J Prosthet Dent 1998; 80: 269-273.
13. Browning WD.Incidence and severity of postoperative pain following routine placement of amalgam restorations. Quintessence Int. 1999 ;30:484-489.
14. Gordan, V., Mjör, J., Hucke, R., Smith, G. Effect of different liner treatments on postoperative sensitivity of amalgam restorations. Quintessence Int 1999; 30: 55-59.
15. Kennington LB, Davis RD, Murchison DF, Langenderfer WR Short-term clinical evaluation of
post-operative sensitivitywith bonded amalgamsAmJ Dent. 1998;11:177-180.
16. Grover PS, Hollinger J, Lorton L. A review of the incidence of pain after an operative treatment visit: Part I. JProsthetDent 1984; 51:224-225.
17. Miller BC, Charbeneau GT. Sensitivity of teeth with andwithout cement bases under malgamrestorations: a clinical study.OperDent 1984 ; 9:130-135.
18. Stanely HR. Pulpal response to ionomer cements- Biological characteristics. J Am Dent Assoc 1990;
19. BrannstromM,Nordenvall K-J. Bacterial penetration, pulpal reaction and the inner surface of Concise
enamel bond: composite fillings in etched and unetched cavities. JDent Res 1978; 57:3-10
20. Brannstrom M, Astrom A. The hydrodynamics of dentine: it’s possible relationship to dental pain. Int Dent J 1972; 22: 219-227
21. Browning WD. Incidence and severity of postoperative pain following routine placement of amalgam restorations. Quintessence Int. 1999;30: 484-489.
22. BrowningWD, Blalock JS, Callan RS, BrackettWW, Schull GF, Davenport MB, Brackett MG. Postoperative sensitivity: a comparison of two bonding agents.OperDent. 2007 ;32:112-117.
23. Mahler DB, Engle JH, Simms LE, Terkla LG. Oneyear clinical evaluation of bonded amalgam restorations. JAmDentAssoc 1996;127:345-349.
24. Pashley DH, Michelich V, Kehl T. Dentin permeability: effects of smear layer removal. J ProsthetDent 1981; 46 :531-537.
25. Gilpatrick RO, JohnsonWW,Moore DS. Histology of human pulp after etching with 10% phosphoric acid
(Abstract 2442). JDent Res 1994; 73:407.
26. Balanko M. Bonded silver amalgam restorations. J EsthetDent. 1992 ; 4:54-57.