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Evaluation of efficacy of different surface treatment protocols by laser fluorescence: an invitro study

Lt Col Sonali Sharma

Classified Specialist, Command Military Dental Centre, Western Command, Chandimandir, India

E-mail : bhuvaneswari.bibleraaj@uhsm.nhs.uk

Mithra N. Hegde

Vice Principal, Dean of Dental Faculty, Head of the Department of Conservative Dentistry and Endodontics, A. B. Shetty Memorial Institute of Dental Sciences, Nitte University, Deralakatte, Mangaluru, India

Vandana Sadananda

Post graduate student, Department of Conservative Dentistry and Endodontics, A. B. Shetty Memorial Institute of Dental Sciences, Nitte University, Deralakatte, Mangaluru, India

Blessen Matthews

Post graduate student, Department of Conservative Dentistry and Endodontics, A. B. Shetty Memorial Institute of Dental Sciences, Nitte University, Deralakatte, Mangaluru, India

DOI: 10.15761/DOCR.1000207

Article
Article Info
Author Info
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Abstract

Background: Demineralization and remineralisation of enamel are occurring concomitantly in oral cavity. Fluorides and other remineralizing pastes alone or along with high powered lasers to harnesses the remineralization potentiality of the tooth have been used with varying results. Low powered lasers like aluminium gallium arsenide lasers are being evaluated to bring about caries inhibition.

Aim: The aim of the study was to evaluate caries inhibitory potentiality of aluminium gallium arsenide laser.

Material and method: 54 extracted intact posterior teeth were selected. They were sectioned mesio - distally and coated with nail varnish so to obtain windows of 3mm X 3mm.The samples were then divided so that each group and sub group has 6 samples each. Group 1: Control; Group 2 A: Laser irradiation with 2 watts for 30 secs; Group 2 B: Laser Irradiation with 3 watts for 30 secs; Group 3: Enafix Paste for 1 hour; Group 4: CPP-ACPF remineralizing paste for 1hour; Group 5 A: Laser Irradiation 2 watts for 30 secs followed by application of Enafix for 1 hour; Group 5 B: Laser Irradiation 3 watts for 30 secs followed by application of Enafix for 1 hour; Group 6 A: Laser Irradiation 2 watts for 30 secs followed by application of CPP-ACPF for 1 hour; Group 6 B: Laser Irradiation 3 watts for 30 secs followed by application of CPP-ACPF for 1 hour. The control group had no treatment done on it and baseline values recorded by laser fluorescence device. All Groups except control group were demineralised by 30% phosphoric acid for 20 secs and laser fluorescence values noted. The groups were surface treated and the laser fluorescence readings were recorded.

Results: The data was collected and statistical analysis was done by paired ‘t’ test to compare control and test goup and one way analysis of variance ANOVA test. A significant difference between three or more sample means was revealed by an ANOVA, hence for multiple comparison Tukey HSD Post hoc Tests were undertaken.

Conclusion: The laser irradiation of 2 watts followed by CPP-ACPF application was observed as the most effective surface treatment modality.

Key words

surface treatment, aluminum gallium arsenide laser, laser fluorescence, caries inhibition

Introduction

Current knowledge of the caries is based on understanding the caries continuum process. Dental caries is a dynamic progressive disease of tooth with varying phases of demineralization and remineralization. Thus, the thrust in caries management has moved away from restorative phase to detecting caries at an early non-cavitated stage and risk assessment to determine appropriate preventive, intervention and recall frequency [1-3].

Primary prevention aims at preventing caries before it occurs clinically. It is most effectively done by preventing exposure to what causes the disease, by caries risk assessment and modifying unhealthy behaviours and by increasing resistance to the disease. In addition to addressing the goal of primary prevention of caries, secondary preventive modalities cannot be ignored. Secondary prevention comes into play when caries has progressed to a stage which is clinically detectable i.e. non-cavitated lesion [4,5].

The immediate need based preventive care of a specific incipient lesion once it is detected and assessed is to inhibit the progression of the lesion to a stage of surgical intervention. For secondary prevention many modalities like fluoride has been used alone or in combination with non-fluoride remineralizing agents like CPP-ACP (Casein phosphopeptide-amorphous calcium phosphate) [4-6].

The aim of this study was to evaluate the efficacy of different surface reminerlizing protocols.

Material and methods

  1. Laser fluorescence device (DIAGNOdent pen 2190 KaVo, Biberach, Germany)
  2. Aluminium Gallium Arsenide Laser (White star TM, Creation, Verona, Italy)
  3. Casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF) paste
  4. Calcium sucrose phosphate (ENAFIX) paste
  5. 30 % phosphoric acid gel

Procedure

54 freshly extracted intact teeth were selected, disinfected and sectioned mesiodistally. They were coated with nail varnish so as to obtain a window of 3mm X 3mm.

6 samples each were assigned to the following groups and then surface treated as follows

Group 1: Control.

Group 2 A: Laser irradiation with 2 watts for 30 secs.

Group 2 B: Laser Irradiation with 3 watts for 30 secs.

Group 3: Enafix Paste for 1 hour.

Group 4: CPP-ACPF remineralizing paste for 1hour.

Group 5 A: Laser Irradiation 2 watts for 30 secs followed by application of Enafix for 1 hour .

Group 5 B: Laser Irradiation 3 watts for 30 secs followed by application of Enafix for 1 hour.

Group 6 A: Laser Irradiation 2 watts for 30 secs followed by application of CPP-ACPF for 1 hour.

Group 6 B: Laser Irradiation 3 watts for 30 secs followed by application of CPP-ACPF for 1 hour.

All groups and sub groups were initially assessed by Laser fluorescence and baseline values noted. All the test groups and subgroups were demineralized by 30 percent phosphoric acid and the values were noted by Laser fluorescence.

After demineralization, treatment groups were again surface treated as already quoted above.

The laser fluorescence values were then recorded for each group and subgroup.

The data was collected and statistical analysis was done by paired ‘t’ test to compare control and test goup and one way analysis of variance ANOVA test. A significant difference between three or more sample means was revealed by an ANOVA, hence for multiple comparison Tukey HSD Post hoc Tests were undertaken (Tables 1 & 2).

Table 1. Between treated groups there is a significant difference at 99 % confidence level hence post hoc test undertaken.

ANOVA

 

Sum of Squares

df

Mean Square

F

Significance

CONTROL

Between Groups

21.563

4

5.391

1.878

0.132

Within Groups

123.417

43

2.87

 

 

Total

144.979

47

 

 

 

DEMINERALIZED

Between Groups

155.729

4

38.932

1.467

0.229

Within Groups

1141.25

43

26.541

 

 

Total

1296.979

47

 

 

 

TREATED

Between Groups

586.312

4

146.578

16.565

<0.001

Within Groups

380.5

43

8.849

 

 

Total

966.812

47

 

 

 

Table 2. Post Hoc Tests.

Tukey HSD           Multiple Comparisons

Dependent
Variable

(I) Group

(J) Group

Mean Difference (I-J)

Standard Error

Significance

95% Confidence Interval

Lower Bound

Upper Bound

TreatDiff

GROUP 2A

GROUP 2B

-0.5

1.59513

1

-5.5988

4.5988

GROUP 3

-5.83333*

1.59513

0.015

-10.9322

-0.7345

GROUP 4

-7.00000*

1.59513

0.002

-12.0988

-1.9012

GROUP 5A

-2.5

1.59513

0.766

-7.5988

2.5988

GROUP 5B

0.66667

1.59513

1

-4.4322

5.7655

GROUP 6A

3.83333

1.59513

0.268

-1.2655

8.9322

GROUP 6B

1.66667

1.59513

0.964

-3.4322

6.7655

GROUP 2B

GROUP 2A

0.5

1.59513

1

-4.5988

5.5988

GROUP 3

-5.33333*

1.59513

0.035

-10.4322

-0.2345

GROUP 4

-6.50000*

1.59513

0.005

-11.5988

-1.4012

GROUP 5A

-2

1.59513

0.91

-7.0988

3.0988

GROUP 5B

1.16667

1.59513

0.995

-3.9322

6.2655

GROUP 6A

4.33333

1.59513

0.147

-0.7655

9.4322

GROUP 6B

2.16667

1.59513

0.87

-2.9322

7.2655

GROUP 3

GROUP 2A

5.83333*

1.59513

0.015

0.7345

10.9322

GROUP 2B

5.33333*

1.59513

0.035

0.2345

10.4322

GROUP 4

-1.16667

1.59513

0.995

-6.2655

3.9322

GROUP 5A

3.33333

1.59513

0.439

-1.7655

8.4322

GROUP 5B

6.50000*

1.59513

0.005

1.4012

11.5988

GROUP 6A

9.66667*

1.59513

0

4.5678

14.7655

GROUP 6B

7.50000*

1.59513

0.001

2.4012

12.5988

GROUP 4

GROUP 2A

7.00000*

1.59513

0.002

1.9012

12.0988

GROUP 2B

6.50000*

1.59513

0.005

1.4012

11.5988

GROUP 3

1.16667

1.59513

0.995

-3.9322

6.2655

GROUP 5A

4.5

1.59513

0.118

-0.5988

9.5988

GROUP 5B

7.66667*

1.59513

0.001

2.5678

12.7655

GROUP 6A

10.83333*

1.59513

0

5.7345

15.9322

GROUP 6B

8.66667*

1.59513

0

3.5678

13.7655

GROUP 5A

GROUP 2A

2.5

1.59513

0.766

-2.5988

7.5988

GROUP 2B

2

1.59513

0.91

-3.0988

7.0988

GROUP 3

-3.33333

1.59513

0.439

-8.4322

1.7655

GROUP 4

-4.5

1.59513

0.118

-9.5988

0.5988

GROUP 5B

3.16667

1.59513

0.504

-1.9322

8.2655

GROUP 6A

6.33333*

1.59513

0.006

1.2345

11.4322

GROUP 6B

4.16667

1.59513

0.182

-0.9322

9.2655

GROUP 5B

GROUP 2A

-0.66667

1.59513

1

-5.7655

4.4322

GROUP 2B

-1.16667

1.59513

0.995

-6.2655

3.9322

GROUP 3

-6.50000*

1.59513

0.005

-11.5988

-1.4012

GROUP 4

-7.66667*

1.59513

0.001

-12.7655

-2.5678

GROUP 5A

-3.16667

1.59513

0.504

-8.2655

1.9322

GROUP 6A

3.16667

1.59513

0.504

-1.9322

8.2655

GROUP 6B

1

1.59513

0.998

-4.0988

6.0988

GROUP 6A

GROUP 2A

-3.83333

1.59513

0.268

-8.9322

1.2655

GROUP 2B

-4.33333

1.59513

0.147

-9.4322

0.7655

GROUP 3

-9.66667*

1.59513

0

-14.7655

-4.5678

GROUP 4

-10.83333*

1.59513

0

-15.9322

-5.7345

GROUP 5A

-6.33333*

1.59513

0.006

-11.4322

-1.2345

GROUP 5B

-3.16667

1.59513

0.504

-8.2655

1.9322

GROUP 6B

-2.16667

1.59513

0.87

-7.2655

2.9322

GROUP 6B

GROUP 2A

-1.66667

1.59513

0.964

-6.7655

3.4322

GROUP 2B

-2.16667

1.59513

0.87

-7.2655

2.9322

GROUP 3

-7.50000*

1.59513

0.001

-12.5988

-2.4012

GROUP 4

-8.66667*

1.59513

0

-13.7655

-3.5678

GROUP 5A

-4.16667

1.59513

0.182

-9.2655

0.9322

GROUP 5B

-1

1.59513

0.998

-6.0988

4.0988

GROUP 6A

2.16667

1.59513

0.87

-2.9322

7.2655

*. The mean difference is significant at the 0.05 level.

There is significant difference with 99% confidence level for GROUP 6A and 6B. The inference drawn is that laser irradiation of 2 watts and 3 watts followed by CPP -ACPF application give the best result. GROUP 5B, 3 & 4 show significant difference with 95 % confidence level.

Results

Graph 1A: Comparision of all groups

GROUP 6A i.e 2 watts laser followed by application of CPP-ACPF has shown to give optimum results. All groups in which laser treatment has been done gives a better result as compared to the paste application when used.

Graph 2: Difference in surface treatment

GROUP 6A that is 2 watts laser followed by application of CPP-ACPF has shown to given best results. All groups in which laser treatment has been done gives a better result as compared to the paste application when used alone.

Discussion

Caries prevention and management strategies are directed towards making enamel more resistant towards dissolution by acidic challenges of oral cavity. The caries progression may be halted or reduced by the use of risk modifiers. Fluoride is an effective therapeutic risk modifier and preventive agent for dental caries. Fluoride has played an important role in the prevention of dental caries since the introduction of water fluoridation in the 1940s. The reduction of demineralization and enhancement of remineralization is due to the basic fluoride ions irrespective of the vehicle [7-8].

Jayarajan J, et al. conducted an invitro comparative study of the remineralizing potentiality of CPP-ACP and CPP-ACPF. Due to inclusion of NaF in CPP-ACPF, it showed better remineralizing potential than CPP-ACP alone [9]. Preethee T, Kandaswamy D observed that CPP-ACPF had superior remineralizing potential than that of CPP-ACP and Novamin [10]. Chole, et al. reviewed the contemporary remineralizing agents available for remineralization and their implementation in clinical practice. CPP-ACPF, Bioactive glass, NovaMin and Clinpro were reviewed and authors inferred that amongst this CPP-ACPF is best remineralizing material because it incorporated fluoride and stabilizes ACP, which is very unstable when used alone [11].

Fluoride ions require a high concentration of 5000 ppm to penetrate to subsurface layer hence its role in remineralizing sub surface lesions is doubtful [12]. CPP-ACP products if ingested in significant quantities will cause side effects. The effectiveness of CPP-ACP in remineralizing subsurface lesion is questionable. Another limitation is that repeated application of remineralizing paste is needed to maintain and replenish a constant supply of the lost remineralizing ions [13]. Hence a surface treatment protocol is needed which gives the optimum results by bringing about a change in enamel crystal.

Since 1960, when the first laser was developed by Maiman, lasers have been experimented with the aim to improve acid resistance [14]. Niazy MA in an in vitro study observed that there was a synergistic effect of CO2 laser and CPP ACP on enamel and root caries [15]. Powell GL reviewed different lasers used in prevention of dental caries. The lasers he analysed were Er: YAG, Er: YSGG, Nd: YAG, Diode, CO2, Argon. He inferred that lasers per se have some role in inhibiting caries but their efficacy increases when they are supplemented with remineralizing solutions. The argon laser seems to be the most widely used laser in caries inhibition [16].

Lasers like CO2, Nd: YAG, Erbium: YAG have all said to have a caries inhibitory role. These lasers had disadvantage of high cost, being bulky and result obtained was debatable. Further, most of the studies evaluating the high-power lasers are invitro studies [14,17,18]. Aluminium gallium arsenide laser has been hypothesized to increase acid resistance and the advantage is low cost and portability [17]. Thus, in this study different surface treatment were compared. Lasers of 2 wattage followed by application of CPP-ACPF has shown to give best results. The results were statistically significant. The next best results were observed with Lasers of 3 wattage followed by application of CPP ACP F. Thereafter it was the laser irradiation done alone groups which showed promising results. The Laser irradiation followed by Enafix application came next. Remineralizing paste when used alone was the least effective surface treatment modality (Graphs 1 & 2).

Moriyama et al in an in vitro study evaluated the effectiveness of fluorescence based methods to detect insitu demineralization and remineralization on smooth surfaces. The devices compared were DIAGNOdent, DIAGNOdent Pen, Vista Proof Camera. It was concluded that DIAGNOdent and DIAGNOdent pen were more effective diagnostic tool to detect insitu demineralization and remineralization on smooth surfaces [19]. Guerrieri discusses the various caries detection method which are available for detection of caries and stressed that diagnostic devices like laser fluorescence can monitor the regression or progression of early carious lesions [20]. Patil N in an invitro study used laser fluorescence device to evaluate the remineralizing potentiality of CPP -ACP, CPP-ACPF and tricalcium phosphate fluoride. Remineralization efficacy was greatest in TCP-F followed by CPP-ACPF and least in CPP-ACP [21]. Thus laser fluorescence device was used for evaluating and monitoring demineralization and remineralization in samples. The laser fluorescence values of control were noted as baseline. The demineralized samples show an increase in laser fluorescence values. After surface treatment the group which came closest to that of control values was the most effective surface treatment modality.

Conclusion

1. The laser irradiation of 2 watts followed by CPP-ACPF application was observed as the most effective surface treatment modality.

2. Laser irradiation per se brought the laser fluorescence values closer to the preoperative control values.

Acknowledgement

Mr. S. S. Tanwar for statistical analysis.

References

  1. Dental caries: The disease and its clinical management. FejerskovO, Nyvad B,Kidd E. Edn 2015. Wiley Blackwell.
  2. Hicks J, Godoy FG, Flaitz C (2004) Biological factors in dental caries enamel structure and the caries process in the dynamic process of demineralization and remineralisation (part 2). J Clin Pediatr Dent 28: 119-124. [Crossref]
  3. Featherstone JD (2008) Dental caries: a dynamic disease process. Aust Dent J 53: 286-291. [crossref] 
  4. Godoy FG, Hicks J (2008) Maintaining the integrity of the enamel surface. The role of dental biofilm, saliva and preventive agents in enamel demineralization and remineralisation. JADA 139: 25S-34S. [crossref]
  5. Dinesh MD, Uma MS, Meenatchisundaram S, Anjali VM, Athira PS, et al. (2016) Streptococcal Dental Caries – A Short Review. Int J Curr Res Aca Rev 4: 160-170.
  6. Usha C, R S (2009) Dental caries - A complete changeover (Part I). J Conserv Dent 12: 46-54. [crossref] 
  7. American Dental Association Council on Scientific Affairs (2006) Professionally applied topical fluoride: evidence-based clinical recommendations. J Am Dent Assoc 137: 1151-1159. [crossref] 
  8. Rao A, Malhotra N (2011) The role of remineralizing agents in dentistry: a review. Compend Contin Educ Dent 32: 26-33. [crossref] 
  9. Preethee T, Kandaswamy D (2011) Comparing the remineralising potential of novamin and casein phosphopeptide –amorphous calcium phosphate using quantitative light induced fluorescence. Amrita Journal of Medicine 7: 28-31.
  10. Jayarajan J, Janardhanam P, Jayakumar P, Deepika (2011) Efficacy of CPP-ACP and CPP-ACPF on enamel remineralization – An in vitro study using scanning electron microscope and DIAGNOdent. Indian Journal of Dental Research 22: 77-82. [crossref]
  11. Chole D (2016) Remineralizing Agents: Minimal Invasive Therapy a Review. IOSR Journal of Dental and Medical Sciences (IOSR-JDMS) 15; 64-68.
  12. ten Cate JM (2013) Contemporary perspective on the use of fluoride products in caries prevention. Br Dent J 214: 161-167. [crossref]
  13. Reynolds EC (1997) Remineralisation of enamel subsurface lesions by casein phosphopeptide-stabilized calcium phosphate solutions. J Dent Res 76: 1587-95. [crossref]
  14. Lasers in Dentistry (2015) Guide for Clinical Practice. Patricias M de Freitas.
  15. Niazy MA, Abdul Hamid ES (2009) Synergistic caries inhibitory effect of a rematerializing agent and CO2 laser on human enamel and root dentin. Cairo Dental Journal 25: 415-424.
  16. Powel GL (2006) Prevention of dental caries by laser irradiation: A review. J Oral Laser Application 6: 255-257.
  17. Convissar RA (2011) Principle and Practice of Laser Dentistry.
  18. Coluzzi DJ (2004) Fundamentals of dental lasers: science and instruments. Dent Clin North Am 48: 751-770. [crossref] 
  19. Moriyama CM, Rodrigues JA, Lussi A, Diniz MB (2014) Effectiveness of fluorescence-based methods to detect in situ demineralization and remineralization on smooth surfaces. Caries Res 48: 507-514. [crossref] 
  20. Guerrieri A, Gaucher C, Bonte E, Lasfargues JJ (2012) Minimal intervention dentistry: part 4. Detection and diagnosis of initial caries lesions. Br Dent J 213: 551-557. [crossref]
  21. Patil N, Choudhari S, Kulkarni S, Joshi SR (2013) Comparative evaluation of remineralizing potential of three agents on artificially demineralized human enamel: An in vitro study. J Conserv Dent 16: 116-120. [crossref]

Editorial Information

Editor-in-Chief

Shigeru Watanabe
Meikai University

Article Type

Research

Publication history

Received date: February 20, 2017
Accepted date: February 24, 2017
Published date: February 27, 2017

Copyright

© 2017 Sharma S. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Citation

Sharma S, Hegde MN, Sadananda V, Matthews B (2017) Evaluation of efficacy of different surface treatment protocols by laser fluorescence: an invitro study. Dent Oral Craniofac Res 3: DOI: 10.15761/DOCR.1000207

Corresponding author

Dr. Lt Col Sonali Sharma

Classified Specialist, Command Military Dental Centre, Western Command, Chandimandir, India

Graph 1A. Comparison of all groups.

GROUP 6A i.e 2 watts laser followed by application of CPP-ACPF has shown to give best results. All groups in which laser treatment has been done gives a better result as compared to the paste application when used.

Graph 2. Difference in surface treatment.

GROUP 6A that is 2 watts laser followed by application of CPP-ACPF has shown to given best results. All groups in which laser treatment has been done gives a better result as compared to the paste application when used alone.

Table 1. Between treated groups there is a significant difference at 99 % confidence level hence post hoc test undertaken.

ANOVA

 

Sum of Squares

df

Mean Square

F

Significance

CONTROL

Between Groups

21.563

4

5.391

1.878

0.132

Within Groups

123.417

43

2.87

 

 

Total

144.979

47

 

 

 

DEMINERALIZED

Between Groups

155.729

4

38.932

1.467

0.229

Within Groups

1141.25

43

26.541

 

 

Total

1296.979

47

 

 

 

TREATED

Between Groups

586.312

4

146.578

16.565

<0.001

Within Groups

380.5

43

8.849

 

 

Total

966.812

47

 

 

 

Table 2. Post Hoc Tests.

Tukey HSD           Multiple Comparisons

Dependent
Variable

(I) Group

(J) Group

Mean Difference (I-J)

Standard Error

Significance

95% Confidence Interval

Lower Bound

Upper Bound

TreatDiff

GROUP 2A

GROUP 2B

-0.5

1.59513

1

-5.5988

4.5988

GROUP 3

-5.83333*

1.59513

0.015

-10.9322

-0.7345

GROUP 4

-7.00000*

1.59513

0.002

-12.0988

-1.9012

GROUP 5A

-2.5

1.59513

0.766

-7.5988

2.5988

GROUP 5B

0.66667

1.59513

1

-4.4322

5.7655

GROUP 6A

3.83333

1.59513

0.268

-1.2655

8.9322

GROUP 6B

1.66667

1.59513

0.964

-3.4322

6.7655

GROUP 2B

GROUP 2A

0.5

1.59513

1

-4.5988

5.5988

GROUP 3

-5.33333*

1.59513

0.035

-10.4322

-0.2345

GROUP 4

-6.50000*

1.59513

0.005

-11.5988

-1.4012

GROUP 5A

-2

1.59513

0.91

-7.0988

3.0988

GROUP 5B

1.16667

1.59513

0.995

-3.9322

6.2655

GROUP 6A

4.33333

1.59513

0.147

-0.7655

9.4322

GROUP 6B

2.16667

1.59513

0.87

-2.9322

7.2655

GROUP 3

GROUP 2A

5.83333*

1.59513

0.015

0.7345

10.9322

GROUP 2B

5.33333*

1.59513

0.035

0.2345

10.4322

GROUP 4

-1.16667

1.59513

0.995

-6.2655

3.9322

GROUP 5A

3.33333

1.59513

0.439

-1.7655

8.4322

GROUP 5B

6.50000*

1.59513

0.005

1.4012

11.5988

GROUP 6A

9.66667*

1.59513

0

4.5678

14.7655

GROUP 6B

7.50000*

1.59513

0.001

2.4012

12.5988

GROUP 4

GROUP 2A

7.00000*

1.59513

0.002

1.9012

12.0988

GROUP 2B

6.50000*

1.59513

0.005

1.4012

11.5988

GROUP 3

1.16667

1.59513

0.995

-3.9322

6.2655

GROUP 5A

4.5

1.59513

0.118

-0.5988

9.5988

GROUP 5B

7.66667*

1.59513

0.001

2.5678

12.7655

GROUP 6A

10.83333*

1.59513

0

5.7345

15.9322

GROUP 6B

8.66667*

1.59513

0

3.5678

13.7655

GROUP 5A

GROUP 2A

2.5

1.59513

0.766

-2.5988

7.5988

GROUP 2B

2

1.59513

0.91

-3.0988

7.0988

GROUP 3

-3.33333

1.59513

0.439

-8.4322

1.7655

GROUP 4

-4.5

1.59513

0.118

-9.5988

0.5988

GROUP 5B

3.16667

1.59513

0.504

-1.9322

8.2655

GROUP 6A

6.33333*

1.59513

0.006

1.2345

11.4322

GROUP 6B

4.16667

1.59513

0.182

-0.9322

9.2655

GROUP 5B

GROUP 2A

-0.66667

1.59513

1

-5.7655

4.4322

GROUP 2B

-1.16667

1.59513

0.995

-6.2655

3.9322

GROUP 3

-6.50000*

1.59513

0.005

-11.5988

-1.4012

GROUP 4

-7.66667*

1.59513

0.001

-12.7655

-2.5678

GROUP 5A

-3.16667

1.59513

0.504

-8.2655

1.9322

GROUP 6A

3.16667

1.59513

0.504

-1.9322

8.2655

GROUP 6B

1

1.59513

0.998

-4.0988

6.0988

GROUP 6A

GROUP 2A

-3.83333

1.59513

0.268

-8.9322

1.2655

GROUP 2B

-4.33333

1.59513

0.147

-9.4322

0.7655

GROUP 3

-9.66667*

1.59513

0

-14.7655

-4.5678

GROUP 4

-10.83333*

1.59513

0

-15.9322

-5.7345

GROUP 5A

-6.33333*

1.59513

0.006

-11.4322

-1.2345

GROUP 5B

-3.16667

1.59513

0.504

-8.2655

1.9322

GROUP 6B

-2.16667

1.59513

0.87

-7.2655

2.9322

GROUP 6B

GROUP 2A

-1.66667

1.59513

0.964

-6.7655

3.4322

GROUP 2B

-2.16667

1.59513

0.87

-7.2655

2.9322

GROUP 3

-7.50000*

1.59513

0.001

-12.5988

-2.4012

GROUP 4

-8.66667*

1.59513

0

-13.7655

-3.5678

GROUP 5A

-4.16667

1.59513

0.182

-9.2655

0.9322

GROUP 5B

-1

1.59513

0.998

-6.0988

4.0988

GROUP 6A

2.16667

1.59513

0.87

-2.9322

7.2655

*. The mean difference is significant at the 0.05 level.

There is significant difference with 99% confidence level for GROUP 6A and 6B. The inference drawn is that laser irradiation of 2 watts and 3 watts followed by CPP -ACPF application give the best result. GROUP 5B, 3 & 4 show significant difference with 95 % confidence level.