• Users Online: 879
  • Home
  • Print this page
  • Email this page
Home About us Editorial board Ahead of print Current issue Search Archives Submit article Instructions Subscribe Contacts Login 

 Table of Contents  
Year : 2019  |  Volume : 11  |  Issue : 1  |  Page : 42-45

Assessment of efficacy and maintenance of light-curing units in dental offices across Punjab: A clinical survey

Department of Conservative Dentistry and Endodontics, Guru Nanak Dev Dental College and Research Institute, Sunam, Punjab, India

Date of Web Publication19-Feb-2019

Correspondence Address:
Rajinder Bansal
Department of Conservative Dentistry and Endodontics, Guru Nanak Dev Dental College and Research Institute, Sunam - 148 028, Punjab
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/IJDS.IJDS_63_18

Rights and Permissions

Aims and Objectives: Curing units in dental offices across Punjab are analyzed for a practical purpose. Materials and Methods: One thousand light-curing units regularly used by the dentists in dental offices across the state of Punjab were examined for their output intensity. Various factors include as follows: type, power of light-curing unit, material molecule formation on tip (YES/NO), diameter of guide tip, and frequency of bulb replacement. A radiometer, a magnifying glass, and a Vernier caliper were used. Data were collected and analyzed. Results: About 75.80% of dentists use light-emitting diode (LED) lights, while 24.20% utilize halogen lamps to cure dental composites. 36.60% of light-curing units of the state had light intensity below 300 mW/cm2, out of which 61.60% were quartz–tungsten–halogen (QTH) and 28.60% LED light-curing units. 17.40% of light-curing units recorded light intensity between 301 and 400 mW/cm2. 46% of light-curing units registered an output intensity of >400 mW/cm2. 79.60% of light units showed material particle buildup on light-curing tips. 62.40% of dentists never replaced the bulbs of their light-curing units. Two-third of dental the practitioners avoided infection control barriers on the tips of curing units. Conclusions: There is a deficit of knowledge among dental practitioners in Punjab regarding care of light-curing units. Dental light-curing units should be regularly checked and infection control remedies should be opted.

Keywords: Light intensity, light-curing unit, radiometer

How to cite this article:
Bansal R, Bansal M, Walia S, Bansal L, Singh K, Aggarwal R. Assessment of efficacy and maintenance of light-curing units in dental offices across Punjab: A clinical survey. Indian J Dent Sci 2019;11:42-5

How to cite this URL:
Bansal R, Bansal M, Walia S, Bansal L, Singh K, Aggarwal R. Assessment of efficacy and maintenance of light-curing units in dental offices across Punjab: A clinical survey. Indian J Dent Sci [serial online] 2019 [cited 2023 Oct 1];11:42-5. Available from: http://www.ijds.in/text.asp?2019/11/1/42/252513

  Introduction Top

The utilization of visible light to cure dental materials has extended over ongoing years to include a wide range of items, including luting cements, temporary filling materials, periodontal pack materials, reline and impression materials, composite resins, glass ionomers, and bonding agents. Effective utilization of these items specifically depends on correct working of the visible light-curing unit.[1] Light restored composite resins depend on adequate light to accomplish satisfactory polymerization. The effect of the adequate intensity yield of curing lights in guaranteeing the life span of filling materials and keeping away from unfortunate clinical results is all around accepted.[2],[3] As the curing light unit ages, the light yield reduces which prompts deficient polymerization causing minor breakdown, expanded wear, diminished quality, poor shading steadiness and expanded water sorption, secondary caries, pulpal sensitivity, and diminished life span of the restoration.[1],[3],[4] To cure composite of 2-mm thick increment, a power of 400 mW/cm2 is acceptable.[5] Light units with powers of under 300 mW/cm2 are depicted in the literature as inadequate.[6] The strength of light-curing unit conversely corresponds to the diameter of light-curing tip.[7]

The power of curing lights is essentially lessened due to the presence of composite material development on curing tip.[7] Light-curing units are inclined to bacterial tainting after repeated utilization and various measures can be undertaken to decrease and prevent this.

A dental radiometer ought to be utilized intermittently to gauge light intensity and decide if there is a requirement for bulb replacement. This estimation is made on a regular timetable either weekly or monthly, depending on frequency of utilization of the curing light.[8]

  Materials and Methods Top

One thousand light-curing units routinely utilized by the dental practitioners in dental workplaces crosswise over Punjab were analyzed. Consent of the dental practitioner was obtained so as to inspect the light-curing unit in the operatory. Type, output power, diameter of light-curing unit, tip of curing unit, frequency of bulb replacement, and infection control barrier on the device tip were examined.

The radiometer was standardized by estimating the intensity of two curing lights of known intensity. One light-curing unit was light-emitting diode (LED) [Figure 1], while other was quartz-tungsten-halogen (QTH) [Figure 2]. The radiometer [Figure 3] was consistently checked against these light sources.
Figure 1: Light-emitting diode

Click here to view
Figure 2: Quartz–tungsten–halogen

Click here to view
Figure 3: Radiometer

Click here to view

The yield intensity (mW/cm2) of all the examined light-curing units was sorted into three groups:

  1. <300 mW/cm2
  2. In the middle of 301–400 mW/cm2
  3. >401 mW/cm2

    • Examination of light-curing tip – Tip of the light-curing unit was inspected with magnifying glass for the presence/absence of material particles
    • Diameter of light guide tip – Diameter of the light-curing tip was estimated with digital Vernier caliper
    • Frequency of bulb replacement – Dental practitioners were addressed about the history of bulb replacement and their reaction was recorded likewise in months
    • Exercising with infection control on the light-curing device tip – Dental practitioners were put to the question about the application of protection barriers on the light-curing device tip and their reaction was documented.

  Results Top

The information gathered and analyzed demonstrated that 75.80% of dental practitioners utilize LED-curing lights, while 24.20% utilize QTH restoring lights to cure dental composites [Figure 4]. About 36.60% of light-curing units of the state had light intensity beneath 300 mW/cm2, 17.40% of light-curing units recorded light intensity between 301 and 400 mW/cm2, while 46% of light restoring units demonstrated a yield intensity of more than 400 mW/cm2 [Figure 5]. 79.60% of light units showed material particle buildup on light-curing tips [Figure 6].
Figure 4: Percentage of practitioners utilizing QTH and LED light-curing units

Click here to view
Figure 5: Intensity of light-curing units used

Click here to view
Figure 6: Material particle buildup on light-curing tips

Click here to view

Only one-third of dentists used infection control barriers, while two-thirds did not use infection control barriers on the tips of light-curing units [Figure 7]. Nearly 62.40% of dentists never replaced the bulbs of their light-curing units [Figure 8]. About 91.30% of dentists use light guide tip with 8-mm diameter, while only 8.70% of dentists use light guide with diameter of 10 mm to cure composite resins [Figure 9].
Figure 7: Percentage of dentists using infection control barrier on tips of light-curing units

Click here to view
Figure 8: Percentage of dentists who never replaced bulbs of their light-curing units

Click here to view
Figure 9: Percentage of dentists using different tip diameters of light-curing units

Click here to view

  Discussion Top

The utilization of composite resins has expanded in the modern era as a result of expanding patient's interest for all the more esthetically satisfying restorations[9] and visible light-curing units have turned into an integral component of modern adhesive dentistry.[10] QTH lights and LED units are utilized most often in everyday clinical practice.[11] Three-fourth of dental practitioners of the state utilize LED, while just one-fourth utilize QTH-curing lights in dental facilities crosswise over Punjab.

LED technology has a few points of interest contrasted with halogen relieving lights. To start with, unlike halogen lights, LED delivers light inside a limited spectral range. This energy range is almost perfect for activating materials that utilize camphorquinone as a photoactivator. LED requires less power to work; therefore, these are with rechargeable batteries. This component makes them cordless, versatile, and moderately lightweight. Moreover, low-power requirement wipes out the need for a cooling fan since heat delivering infrared wavelengths are eliminated.[12]

Light-cured resin composites depend on adequate intensity of light to accomplish satisfactory polymerization.[13] Yield force of 400 mW/cm2 for 40 s is acceptable to completely cure a 2-mm thick increment.[5] Under experimental conditions, light units with intensities of under 300 mW/cm2 are considered as inadequate.[14] The intensity of light-curing units ought to never dip under 300 mW/cm2 to sufficiently polymerize a 2-mm thick increment of universal shade composite resin.[15] Deficient polymerization of composite resins in more deeper layers cause diminished mechanical properties prompting minor breakdown, expanded wear, diminished quality, poor shading stability, expanded water sorption, and secondary caries.[6]

The adherence of composite resin to the light tip diminishes the productivity of light-curing tip tends to dissipate the light, extensively decreasing the yield power. In this way, the tip ought to be free of composite resin.[13],[16]

About 79.60% of light-curing units indicated composite resin material buildup on light-curing tip. Resin-based composite development has a critical negative impact on irradiance on the grounds that the resin-based composite material hinders the light output.[15],[17]

Light-curing units are utilized for a more extensive scope of clinical applications. As a result of lower irradiance values, bigger diameter tips might be less powerful than smaller diameter tips in polymerizing light-activated materials.[18] Most commonly utilized diameter of light guide tips was 8 mm (91.30%) followed by 10 mm (8.70%) among dental practitioners crosswise over Punjab. The QTH lights have a constrained life expectancy of 100 h because of consecutive degradation during repeated working cycles. QTH bulb replacement ought to be supplanted every 6 months to guarantee ideal performance.[19]

Tainting of light guides and light control unit (LCU) handles is common after clinical utilize. LCU and light guides utilized for curing resins ought not be in direct contact with oral tissues, which can be responsible of transmission of infectious agents from one patient to another.[18],[20],[21]

About 68.10% dental specialists did not utilize contamination control barrier on the tip of light-curing units. The presentation of dental practitioners and auxiliaries to a variety of infectious agents is generally ignored. Light-curing devices are a potential wellspring of infectious diseases because of tainting of the light tip, which specifically contacts oral tissues.

  Conclusions Top

From the present investigation, it can be presumed that there is an absence of awareness among dental practitioners in Punjab with respect to intensity and maintenance of light-curing units. Radiometer ought to be accessible in each dental office for occasional checking of light force of curing unit. Bulb of light-curing unit ought to be supplanted when the intensity of the light-curing unit falls beneath 400 mW/cm2. Tips of ought to be free from any sort of material molecule development. Light-curing tip of minimum diameter and disposable barrier tips ought to be utilized.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Martin FE. A survey of the efficiency of visible light curing units. J Dent 1998;26:239-43.  Back to cited text no. 1
Hegde V, Jadhav S, Aher GB. A clinical survey of the output intensity of 200 light curing units in dental offices across Maharashtra. J Conserv Dent 2009;12:105-8.  Back to cited text no. 2
[PUBMED]  [Full text]  
Pearson GJ, Longman CM. Water sorption and solubility of resin-based materials following inadequate polymerization by a visible-light curing system. J Oral Rehab 1989;16:57-61.  Back to cited text no. 3
Leung RL, Fan PL, Johnston WM. Post irradiation polymerization of visible light-activated composite resin. J Dent Res 1983;62:363-5.  Back to cited text no. 4
Jadhav S, Hegde V, Aher G, Fajandar N. Influence of light curing units on failure of directcomposite restorations. J Conserv Dent 2011;14:225-7.  Back to cited text no. 5
[PUBMED]  [Full text]  
Bansal R, Hora BS, Kumar A, Bansal M, Gupta C, Singla S. Are we doing justice? A clinical survey of the output intensity of light curing units in dental offices. Int J Dent Sci 2012;4:9-11.  Back to cited text no. 6
Christensen R. Practice made perfect dental infection control – Can we call the changes progress. J Esthet Dent 1994;6:135-8.  Back to cited text no. 7
Corciolani G, Vichi A, Davidson CL, Ferrari M. The influence of tip geometry and distance on light-curing efficacy. Oper Dent 2008;33:325-31.  Back to cited text no. 8
El-Mowafy O, El-Badrawy W, Lewis DW, Shokati B, Soliman O, Kermalli J, et al. Efficacy of halogen photopolymerization units in private dental offices in Toronto. J Can Dent Assoc 2005;71:587.  Back to cited text no. 9
Dunn WJ, Bush AC. A comparison of polymerization by light-emitting diode and halogen-based light-curing units. J Am Dent Assoc 2002;133:335-41.  Back to cited text no. 10
Jung H, Friedl KH, Hiller KA, Furch H, Bernhart S, Schmalz G, et al. Polymerization efficiency of different photocuring units through ceramic discs. Oper Dent 2006;31:68-77.  Back to cited text no. 11
Leonard DL, Charlton DG, Roberts HW, Cohen ME. Polymerization efficiency of LED curing lights. J Esthet Restor Dent 2002;14:286-95.  Back to cited text no. 12
Mehta P, Bansal R, Dhawan R, Khatri A. Dental light curing units – A review. Int J Dent Sci 2014;6:125-8.  Back to cited text no. 13
Fan PL, Schumacher RM, Azzolin K, Geary R, Eichmiller FC. Curing-light intensity and depth of cure of resin-based composites tested according to international standards. J Am Dent Assoc 2002;133:429-34.  Back to cited text no. 14
Bayne SC. Dental Materials. Sturdvents, Art and Science of Operative Dentistry. 4th ed. USA: Mosby; 2002. p. 200.  Back to cited text no. 15
McAndrew R, Lynch CD, Pavli M, Bannon A, Milward P. The effect of disposable infection control barriers and physical damage on the power output of light curing units and light curing tips. Br Dent J 2011;210:E12.  Back to cited text no. 16
Maghaireh GA, Alzraikat H, Taha NA. Assessing the irradiance delivered from light-curing units in private dental offices in Jordan. J Am Dent Assoc 2013;144:922-7.  Back to cited text no. 17
Rueggeberg FA, Caughman WF. Factors affecting light transmission of single-use, plastic light-curing tips. Oper Dent 1998;23:179-84.  Back to cited text no. 18
Friedman J. Variability of lamp characteristics in dental curing lights. J Esthet Dent 1989;1:189-90.  Back to cited text no. 19
Shortall AC, Harrington E, Wilson HJ. Light curing unit effectiveness assessed by dental radiometers. J Dent 1995;23:227-32.  Back to cited text no. 20
Chong SL, Lam YK, Lee FK, Ramalingam L, Yeo AC, Lim CC, et al. Effect of various infection-control methods for light-cure units on the cure of composite resins. Oper Dent 1998;23:150-4.  Back to cited text no. 21


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]

This article has been cited by
Ariana Lucía Bravo Lozano, Andrea Nicole Peralta Avila, Esteban Fernando Lima Tola, Manuel Estuardo Bravo Calderon
[Pubmed] | [DOI]
Milton Alexis Quinchiguano Caraguay, David Ismael Bravo Achundia , Esteban Eduardo Amoroso Calle, Manuel Estuardo Bravo Calderon
[Pubmed] | [DOI]
3 Effect of infection control barriers on the light output from a multi-peak light curing unit
Carlos José Soares,Stella Sueli Lourenço Braga,Maria Tereza Hordones Ribeiro,Richard Bengt Price
Journal of Dentistry. 2020; 103: 103503
[Pubmed] | [DOI]
4 The light-curing unit: An essential piece of dental equipment
Richard B. Price,Jack L. Ferracane,Reinhard Hickel,Braden Sullivan
International Dental Journal. 2020;
[Pubmed] | [DOI]
5 Irradiance of different curing modes of common light cure devices: An in vitro study
HaniM Nassar,Mahmoud Almutairi,Albaraa Makhdom
Journal of International Society of Preventive and Community Dentistry. 2020; 10(2): 177
[Pubmed] | [DOI]
6 Effect of Contamination, Damage and Barriers on the Light Output of Light-Curing Units
Abdulhaq A. Suliman,Ahmad A. Abdo,Hussein A. Elmasmari
The Open Dentistry Journal. 2019; 13(1): 196
[Pubmed] | [DOI]


Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

  In this article
Materials and Me...
Article Figures

 Article Access Statistics
    PDF Downloaded413    
    Comments [Add]    
    Cited by others 6    

Recommend this journal