Post-operative sensitivity after resin composite restorations, Possible cause and measures that can be applied to reduce this problem during the placement.

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Published: Wednesday, 03 December 2014 09:34 Written by 

Dr. Ala Mohammed Ajaj, DDS. MSc Aesthetic Dentistry, Kings College London

INTRODUCTION
The use of composite resin as a restorative material for posterior teeth is gaining popularity amongst dentists as it offers more aesthetic replacement to enamel and dentine, and patient’s positively appreciate a better looking filling materials.


This type of treatment (as most treatment procedures) presents with advantages and disadvantages. One of the most common disadvantages is the postoperative sensitivity,

A) CAUSES OF POSTOPERATIVE SENSITIVITY:

 

1. Deep cavity preparation
It was reported that small and medium cavities restored with composite caused less postoperative sensitivity than in deeper cavities, regardless of presence or absence of protective layers. (1)

2. Age of patient
Young patients have larger pulp chambers and larger dentinal tubules, making it more likely that their teeth would be more sensitive to hydrodynamic stimuli (1).

3. IMPROPER ISOLATION
Improper isolation during etching, bonding and composite application can affect the bond strength and will contaminate materials reducing the optimum properties of the restoration. Blood, saliva and crevicular fluid will all adversely affect adhesion (2)


4. SETTING CONTRACTION (POLYMERIZATION SHRINKAGE)


*the total amount of volumetric contraction that occurs depends on:

1) Bulk of material used.
2) Cavity size
3) Clinical technique
* (3)


• Hydrodynamic effects of fluids in dentinal tubules increases in deeper cavities, causing ingress of microbial products (1) This effect starts in the first (24-36 hours)
• Stress on cusps (resulting in micro-cracks) during material shrinkage can cause post-operative sensitivity (3)
• Partial or total bond failure may result in loss of the restoration, post-operative sensitivity or marginal gap formation, (4.5)
• As C factor increases with increased ratio of bonded to non-bonded material placed, the stress on cavity walls increases with increased C factor (6)
(SHRINKAGE PERCENTAGE OF VARIOUS TYPES OF COMPOSITES)

Composite classification Volume shrinkage %
Hybrid 1.6 - 4.7
Nanohybird 2.0 – 3.4
Microfills 2 - 3
Flowables 4 - 8
Compomers 2.6 – 3.4
*TABLE Modified from {Aaron D. Puckett, James G. Fitchie, Pia Chaterjee Kirk, Jefferson Gamblin, Direct Composite Restorative Materials
Dent Clin N Am 51 (2007) 659–675}


5. High occlusal point and masticatory stress.
High points or interferences may cause discomfort as Satangel reported some post-operative symptoms would resolve after occlusal adjustments (7)
In vivo study examination revealed that mastication of solid food and loading of composite filling caused sensitivity in 28 restorations out of total 144 fillings. {19.4 %} (8).
A higher percentage {29%} of symptoms was earlier reported (7)

6. BIOCOMPATIBILITY OF MATERIALS
Monomers considered being potentially harmful, good curing will result in strong bond polymers with more biocompatible properties. (3)
Curing light best placed as close as possible to material to be cured.


B) MEASURES THAT CAN REDUCE POST OPERATIVE SENSITIVITY DURING PLACEMENT OF POSTERIOR COMPOSITE:

 

1. Importance of isolation:
Etched enamel and dentine should be protected from saliva and other fluids.
Rubber dam application is an important isolation measure, which is important for predictable bonding process. (2) Effort spent in good isolation is gained back with good bond strength. It's also recommended to use a diluted sodium hypochlorite or chlorhexidine solution on a cotton pellet to clean and disinfect the exposed dentine prior to bonding.
Thorough cleaning the enamel by means of non-fluoride containing paste and prophylaxis brush, Or sand blasting to insure maximum bonding strength without interfering layer of stain or plaque.

2. Minimal invasive tooth preparation:
It’s important to preserve maximum amount of natural tooth substance as retention of the composite is gained with bonding strength not cavity design as for amalgam (15). Prior to cavity preparation the occlusal contacts should be marked using articulating paper and careful placement of restoration margin away from direct occlusal forces.

3. Avoiding the tendency of over drying (desiccating) dentine:
Slight rehydration of dentine after etching and just before bond agent application with small cotton moistened with distilled water avoids post-operative sensitivity.

4. Use of liner or base in deep cavities:
As the cavity increases in depth the need for protective methods (liner and base) increases in close vicinity to the pulp. (1)
RMGIc can reduce the dentine permeability by penetrating dentinal tubules as proven using scanning electron microscopy (SEM), therefore reducing dentine sensitivity (9)

3) Steps to reduce polymerization shrinkage

• Layering placement of composite:
Incremental application of less than 1.5mm thickness of composite layers to achieve acceptable cure of each layer. (10)
Smaller layers when darker shades of dentine are used to allow curing light penetration for proper curing.


*Incremental techniques: there have been two techniques for incremental curing described:
1. The herringbone method, placing composite in diagonal increments.
2. Lateral incremental filling technique.
Both minimize the wall-to-wall effect of shrinkage*(3)

Herringbone and lateral filling methods. (Image from John F. McCabe and Angus W.G. Walls, Applied Dental Materials, Ninth Edition)

• Reduction of configuration factor:
Applying the composite as a wedge or triangles shape to contact the cavity floor and one wall at each increment, thus reduces the C factor. (10)


Image from; Louis Mackenzie, Adrian CC Shortall and FJ Trevor Burke. Direct Posterior Composite: A Practical Guide. Dent Update 2009; 36: 71–95


• The use of Stress breaking liners:
The use of RMGIC can reduce stress transmitted to cavity walls and pulp floor (11)

• Soft start curing:
Ramped or soft start curing can help reduce shrinkage stress and better polymerization (12)

• Directional curing technique:
As composite closest to light starts to cure first, the reminder of material will shrink to words the light, marginal seal probably maintained when light directed from lateral walls. (3)
• Using light transmitting matrix and wedges:
Will help cure the deep cervical increment in class II restorations. (3) In-vitro studies have demonstrated less microlakage in cervical cavities when transparent matrix and wedges are used. (8)

• The use of macrofillers (inserts):
Using the cerana inserts leads to less composite shrinkage, and probably less post-operative sensitivity. (13)

Placement of composite resin then Cerana insert is positioned and pressure applied against the matrix band. Image from {B J Millar& P B Robinson.Eight year results with direct ceramic restorations (Cerana) British Dental Journal 2006. 201, 515 – 520}

• THE USE OF SILORANE (LOW SHRINKAGE MATERIALS)
New silorane containing materials provides less polymerization stress compared to conventional composites with no or very little compromise of mechanical properties (14)

• FINISHING AND POLISHING
OPDAM et al found that delayed finishing and polishing of composite resulted in a better marginal quality compared to immediate finished and polished restoration. (8)

CONCLUSION:
Composite material is becoming the material of choice for restoration of posterior teeth due to the aesthetic appearance and the fact its more conservative to natural tooth structure.
Good understanding of properties and sensitive technique that should be respected leads to better results and less complications.
With the introduction of low shrinkage material even better results are expected, this may lead amalgam to be of a very limited use.


REFERENCES:

1) M. Unemori, Y. Matsuya, A. Akashi, Y. Goto, A. Akamine Composite resin restoration and postoperative sensitivity: clinical follow-up in an undergraduate program Journal of Dentistry 29 (2001) 7-13
2) Javaheri D. Placement technique for direct posterior composite restorations. Pract Proced Aeshet Dent 2001; 13: 195−200.
3) John F. McCabe and Angus W.G. Walls, Applied Dental Materials, Ninth Edition
4) Louis Makckenzie, Adrian CC Shortall and Trevor Burke. Direct Posterior Composite: A Practical guide. Dental update. March 2009; 36: 71–95.
5) Summitt JB, Robbins JW, Hilton TJ, Schwartz RS, Santos JD. Fundamentals of Operative Dentistry: A Contemporary Approach. Illinois, USA: Quintessence Books, 2006; 289−339.
6) Santini A, Ivanovic V, Ibbetson R, Milia E. Influence of cavity configu-
ration on microleakage around Class V restorations bonded with seven
Self-etching adhesives. J Esthet Restor Dent 2004; 16:128-35.
7) Stangel and R.Y. Barolet McGill. Clinical evaluation of two posterior composite resins: two-year results Journal of Oral Rehabilitation, 1990, Volume 17, pages 257-268
8) Opdam NJ, Roeters FJ, Feilzer AJ, Verdonschot EH. Marginal integrity and postoperative sensitivity in Class 2 resin composite restorations in vivo. J Dent 1998;26:555-62.
9) Richard P. Rusin. Kelli Agee b, Michael Suchko, David H. Pashley Effect of a new liner/base on human dentin permeability journal of dentistry 38 (2010) 245–252.
10) David klaff. Blending incremental and stratified layering technique to produce an estetic posterior composite resin restoration with a predictable prognosis. J esthetic resto dent 13:101-103,2001
11) Tolidis K, Nebecourt A, Randall RC. Effect of resin modified glass ionomer liner on volumetric polymerization shrinkage of various composites. Dent Mater 1998; 14:417-423
12) Sakaguchi RL, Berge HX. Reduced light energy density decreases post-gel contraction while maintaining degree of conversion of composite. J Dent 1998;26:695-700
13) B J Millar& P B Robinson.Eight year results with direct ceramic restorations (Cerana) British Dental Journal 2006. 201, 515 - 520
14) J. David Eicka, Shiva P. Kothaa, Cecil C. Chappelowb, Kathleen V. Kilwayc, Gregory J. Giesec, Alan G. Glarosd, Charles S. Pinzinob, Properties of silorane-based dental resins and composites containing a stress-reducing monomer dental materials 23 (2007) 1011–1017
15) Simona Delipera, David Alleman. Stress-Reduction Protocols For Direct Composite Restorations In Minimally Invasive Cavity Preparations. Pract Proced Aesthet Dent. 2009; 21(2): E1-E6

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