WHITE SPOT LESIONS IN ORTHODONTICS

SEMINAR

1. WHITE SPOT LESIONS IN ORTHODONTICS DR SHEHNAZ JAHANGIR FINAL YEAR MDS DEPT. OF ORTHODONTICS & DENTOFACIAL ORTHOPAEDICS

2. CONTENTS Introduction Definition Incidence Formation of white spot lesions Classification Prevalence Diagnosis Prevention of WSLs Effects of fluoride Remineralisation Conclusion References

3. Introduction Esthetics is a very important reason for which patients seek orthodontic treatment. The introduction of fixed appliances has proved to be a boon for the orthodontists as well as orthodontic patients with several advantages such as shorter treatment time, precise and more controlled tooth movement etc. However the advent of bonded multibracket fixed appliances in 1970s brought enamel white spot lesions.

4. Decalcification of the enamel surface adjacent to fixed orthodontic appliances is an important and prevalent iatrogenic effect of orthodontic therapy. The banding and bonding of orthodontic appliances to teeth increases the plaque retention sites and as a result, oral hygiene becomes more difficult. The low pH of plaque adjacent to orthodontic brackets hinders the remineralisation process and decalcification of enamel can occur.

5. As enamel translucency is directly related to the degree of mineralization, initial enamel demineralization usually manifests itself as “white spot lesion .”

6. Definition : Subsurface enamel porosity from carious demineralization that presents itself as “milky white opacity when located on smooth surfaces”

7. Incidence In general, orthodontic patients have significantly more WSLs than non-orthodontic patients, and these WSLs may present aesthetic problems years after treatment . One study found that the prevalence of at least one WSL in patients who underwent treatment with fixed orthodontic appliances was 49.6%; this compares to only 24% in an untreated control group .

8. This was recently confirmed in a prospective study from the nothern part of norway . About 50% of the patient receiving orthodontic treatment developed one or more WSLs during treatment and 5.7% of the teeth were affected. This compared with a matched group of non orthodontic patients in whom 11% developed WSLs on the labial surface in the same period of time and 0.4% of the teeth were affected.

9. Using more advanced detection techniques like quantitative light-induced fluorescence , Boersma and coworkers observed that 97% of all subjects and on average 30% on the buccal surfaces in the person were affected. On average, 40%of the surfaces in male and 22%in females showed white spot lesions.

10. Formation of white spot lesions: fixed orthodontic appliances rapid increase in the volume of dental plaque low pH increased cariogenic risk, rapid shift in the composition of bacterial flora S. mutans ↑ acid by-products, ↓ pH carious decalcification Fermentable carbohydrates→

11. The first clinical evidence of this demineralization is visualized as white spot lesion. Such lesion have been clinically induced in a span of 4 weeks, which is typically within the time period between one orthodontic appointment and the next. In the highly cariogenic environment adjacent to orthodontic appliances or under loose bands, these lesion can rapidly progress. If left untreated they may produce carious cavitation that will need an appropriate restoration.

12. Classification According to Gorelick and coworkers Small lesion Severe lesion Cavitation .

13. Clinical examination for the presence of white spots was made on the labial surface of individual teeth and , as shown in Fig. , the lesions were scored as follows : In the group that had worn bonded metal orthodontic brackets , all teeth were examined immediately after debonding at the termination of orthodontic treatment. Leonard Gorelick ,* Arnold M. Geiger,** and A. John Gwinnett ***

14. PREVALENCE The greatest prevalence of WSLs was found on the first molars, the canines and the premolars in the orthodontic group . Of the anterior teeth, the lateral incisors were more affected than the central incisors . The most likely reason for this observation is that the brackets are placed closer to the gingival margin because of the anatomic shape of these tooth groups. In the untreated group, the greatest prevalence was observed on the first molars and lower premolars .

15. DIAGNOSIS

16. Evaluation of white spot lesions on teeth with orthodontic brackets Evaluation of demineralized white spot lesions during orthodontic treatment is important for both clinicians and researchers. Clinicians must discover enamel lesions early so that they can advice patients regarding changes in oral hygiene and diet as well as implement suitable preventive measures. There are macroscopic and microscopic methods used in the detection and measurement of demineralized white lesions.

17. Macroscopic methods Rely mainly on the change in the optical properties of enamel with demineralization. A demineralized lesion in enamel is white is due to an increase in the backscatter of light. Clinical examination Clinicians are trained to use clinical examinations to assess the presence of demineralization . Advantages: Simple and inexpensive Clinically valid.

18. Disadvantage Validity – it is often difficult clinically to distinguish white spots caused by demineralization and those that are due to other causes such as developmental hypoplasia or fluorosis . Fluoride opacities White spot lesions

19. 2. Photographic examination Advantages This method can be standardized so that the clinical variability of diagnostic conditions may be minimized . Provides a permanent record and can therefore be examined during one assessment session and re-examined at different time to determine reproducibility.

20. It is easy to mask the patient details so they can be examined in random order to reduce the potential for bias. More versatile than a visual examination . They can also be digitized and using computer to measure the severity of the lesion in terms of area or change in whiteness or gray levels.

21. Disadvantages Might record details differently than the naked eye. Tend to overestimate the incidence of opacities, partly due to the reflection of the flash from the tooth surface. Standardization of the procedures may be difficult particularly with respect to wetness of the tooth.

22. 3. Optical Non- fluoroscent methods Light scattering Demineralization leads to more scattering of the light entering the enamel. The scattering results in sidewards displacement of the light which can be measured using the Optical Caries Monitor. Use a 100w white light as light source and measure backscatter with densitometer. Show good correlation between OCM readings and other more direct but destructive methods of measuring mineral loss.

23. Advantages It enables a convenient and non-destructive quantification of enamel demineralization . Disadvantages Technique sensitive and results can vary with the degree of wetness or drying of the tooth.

24. 4.Optical Fluoroscent Methods : Fluoroscent dye uptake: Mainly used for detection and removal of carious dentin. The disadvantage is that slight procedural variations can result in widely different degrees of dye uptake.

25. Ultraviolet Early studies used ultraviolet light for detection of carious lesion on the smooth surface. Special precautions has to be taken to protect the patient and the operator because UV radiation which has a shorter wavelength than visible light is harmul to eyes and skin.

26. Laser Bjelkhagen and coworkers used an argon laser to show differences in luminescence from intact and carious enamel in the laboratory. De Josselin de Jong and coworkers developed the technique of quantitative laser fluorescence for use in the mouth. The equipment was calibrated to calculate the difference in fluroscence between the demineralized area and the surrounding sound enameland therby quantify mineral loss and lesion size.

27. DIAGNOdent : Does not produce a picture of the tooth, but produces a reading, which is thought to be an indication of bacterial activity, rather than mineral loss.

28. Quantitative Light- Induced Fluorescence Or QLF Most promising fluorescent method of measuring demineralization in use today. Not only does early detection of demineralized lesions, but also detects changes in the mineral loss and size overtime.

29. Microscopic Methods

30. Caries models Microhardness testing Polarized light microscopy Microradiography Allows direct measurement of mineral loss or lesion depth in enamel . Disadvantage Include lack of availability of teeth and only patients requiring extractions can participate. There is less control over lesion reproducibility and restrictions regarding lesion location. The patient cannot commence orthodontic treatment until tooth is extracted

31. The In Situ Caries Model Advantages : Reproduces the natural caries process without causing irreversible damage to the volunteer. Specimen of the same tooth may be kept as a control, allowing a more accurate determination of the changes that occur. It is possible to induce an artificial subsurface lesion in the specimen, so that remineralization as well as further demineralization can be studied. It will not effect the orthodontic treatment

32. Disadvantage Very time consuming particularly in laboratory and analysis time.

33. Prevention of WSLs Perhaps the most important prophylactic measure to prevent the occurrence of WSLs in orthodontic patients is implementing a good oral hygiene regimen including proper tooth brushing with fluoridated dentifrice . Dentifrices typically contain either sodium fluoride, monofluorophosphate , stannous flouride , amine fluoride or a combination . As orthodontic patients are at an increased caries risk, a fluoride concentration below 0.1% in dentifrices is not recommended.

34. In addition to the anti-caries activity, stannous flouride may have plaque inhibiting effect by interfering with the adsorption of plaque bacteria to the enamel surface. Tin atoms-block the passage of sucrose into bacterial cells thus inhibiting acid production. It is observed that the use of fluoridated antiplaque dentifrice may reduce enamel demineralization around brackets more than the use of flouridated dentifrice .

35. For less compliant patients Fluoridated dentifrice alone- ineffective Supplemental sources of fluoride are often suggested Fluoridated mouth rinse containing 0.05% sodium fluoride used daily have been shown to significantly reduce lesion formation beneath the bands. While proper use of these products provide with increased caries protection , patient compliance is required and such co-operation can be difficult to obtain in some patients.

36. The in-office application of a high concentration of fluoride in the form of varnish may be beneficial and should be considered by the clinician. These products offer the combined benefit of delivering high concentration of fluoride during regular orthodontic visit while eliminating the need for patient co-operation. Limitation of frequency of exposures that the patient will receive. Increase cost and chair side time. One disadvantage is the temporary discoloration of the teeth and gingival tissue, with the use of most available products. However it has been reported that the application of a fluoride varnish resulted in 44.3 % reduction in enamel demineralization in orthodontic patients.

37. Recent advances in fluoride prevention Titanium tetrafluoride solutions inhibit lesion development in association with fixed orthodontic appliances markedly & more efficiently than conventional preparations. The cariostatic mechanism of titanium tetrafluoride is probably due to retentive, titanium rich, glaze like surface coating formed on the treated enamel surfaces. At low pH, titanium binds with an oxygen atom of a phosphate group that is densely distributed on enamel surfaces.

38. Following the application of aqueous solutions of titanium tetrafluoride ,-Ti-O-Ti-O chains are formed on the tooth surfaces and covalently bond titanium covers the tooth surface. A strong complex formed is thus formed between the titanium compounds and the hydroxyapatite. This surface coating has been found to resist challenges even under extreme alkaline and acidic conditions.

39. Fluoride and the cariostatic effect

40. Fluoride with no doubt the most important caries preventive agent . For many years it was thought that fluoride should be incorporated into the tooth structure to achieve preventive effect on tooth mineral solubility . Research has shown that the effect is overestimated and that the mechanism is related to fluoride being present in the fluid phase of the caries process . The fluoride ions then execute an inhibiting effect on tooth demineralization and an enhanching effect on tooth remineralization .

41. When topical fluoride is applied , a calcium fluoride-like material builds up in plaque, on the tooth surface or the incipient lesions. The CaF2 acts as a reservoir of the fluoride ions for release when pH is lowered during caries attack . The dissolution rate of CaF2 at different pH is controlled by phosphate and proteins.

42. Importance of pH on the fluoride effect : Arneberg and coworkers studied pH in plaque of orthodontic patients following a sucrose challenge . The lowest pH during resting and fermenting conditions was observed in the plaque of the bonded upper incisors. In these sites, pH could fall to as low as 4. Low pH- any reservoir of fluoride is rapidly lost. The limit of fluoride effect is reached when pH drops so low that even the solubility product of pure fluoroapatite is exceeded.(<4.5).

43. At this low pH the liquid phase of the plaque will be undersaturated with respect to both hydroxyapatite and fluoroapatite and no redeposition of lost mineral occur.

44. Sealants, primers and adhesives: Duration of orthodontic treatment ↑ caries risk. As a result a continuous fluoride release from the bonding system around the bracket base would be extremely beneficial. Thus fluoride containing sealants and adhesives to bond brackets has been attempted .

45. GIC were initially introduced as orthodontic bonding adhesives to take advantage of some of their deisrable characteristics, namely their ability to chemically bond to the tooth structure, in addition to their sustained fluoride release following bonding.

46. Lower bond strength- use for bonding orthodontic brackets fairly limited. In an attempt to increase the bond strength of the GICs, resin particles were added to their formulation to create RMGI bonding systems. Release fluoride like conventional GICs and have high bond strength . Although earlier studies indicate that RMGIs have lower shear bond strength compared with composites resins, particularly within the first half hour after bonding, more recently these products were found to have an increased shear bond strength .

47. Furthermore , it was also reported that no significant differences in bracket failure rates between the RMGIs and composite adhesives . A study showed the mean amount of daily fluoride released by Fuji Ortho LC showed a rapid decrease from day 1 (57 mg/cm2) to day 3 (20.5 mg/cm2). Thereafter, the decrease was significantly less, up to 4.4 mg/cm2 after the third week. The total fluoride released by the adhesive Light Bond during the first month was reported to be 8.73 mg/cm2. It was characterized by an initial burst of fluoride during the first day (5 mg/cm2),followed by gradual tapering down (0.111 mg/cm2 after the third week).

48. According to a recent study teeth bracketed with resin-modified glass ionomer cement had significantly reduced enamel Lds and mineral loss when compared with the composite resin groups. This was obvious for all evaluation methods that have been used. Light Bond paste and sealant, formulated with a patented fluoride-releasing monomer, showed no difference in regard to Ld and mineral loss compared with any nonfluoride -containing Transbond XT group. However, there was a significant difference compared with the values for the resin-modified glass ionomer cement (Fuji Ortho LC).

49. In general, no statistically significant differences were obvious in this study between the sealant Pro Seal group, the self-etching primer Clearfil Protect Bond group , and the self-etching primer Transbond Plus group with the nonfluoride -containing composite Transbond XT for bonding.

50. The fluoridated resin Light Bond, that has been used with its fluoridated sealant, showed no statistical differences in terms of demineralization compared with the nonfluoride -containing composite groups in which only the self-etching primer or the sealant was responsible for the release of fluoride. Light Bond and Pro Seal showed significantly lower Lds compared with a nonbonded control in a recent investigation, whereas no differences were found between the mean Lds of these 2 groups

51. Effects of adding fluoride and other antibacterial agents on shear bond strength of orthodontic adhesives. The application of fluoride containing sealants has been shown to not affect the SBS of orthodontic adhesives and they are able to produce a sustained fluoride release. However, it was determined that the conc. Of fluoride ions released significantly decreased with time. Therefore the important factors that need to be considered by the clinicians using these materials include the duration and conc of fluoride that is being released as well as the ability of these sealants to be recharged with fluoride ions.

52. Recently, it was determined that fluoride releasing sealant ( ProSeal ; reliance orthodontics) was capable of releasing fluoride ions for 17 weeks. While the sealant initially released ions at 0.074ppm/ wk /mm 2 and this level dropped to 0.037ppm/ wk /mm 2 after the first 3 weeks and reached a low of 0.01 by the end of 17 week.

53. Antimicrobials have also been suggested as an adjunct for those patients. Combining chlorhexidine with the bonding primer or applying it after bonding is completed resulted in no significant decrease in SBS. However other methods of incorporating chlorhexidine into the bonding procedure resulted in significantly weaker bond strength. A recent report that evaluated the use of another antimicrobial , cetylpyridinium chloride(CTC ), found no significant differences in tensile bond strength between an adhesive impregnated with 2.5%cetylpyridinium chloride and a control.

54. Moreover the adhesive containing 2.5% CTC was shown to inhibit bacterial growth for 196 days . Additionally it was found that using a combination of an anti-microbial selfetching primer and fluoride releasing primer and a fluoride -releasing adhesive had stronger SBS than conventional composite . In a recent study, a comparision between clearfil protect bond and transbond plus showed that the failure rate with Clearfil Protect Bond was significantly higher than that with Transbond Plus.

55. For patients with adequate oral hygiene, there was no benefit with regard to plaque accumulation and prevention of demineralization with Clearfil Protect Bond . Although the fluoride-releasing effect extends around the bracket, the antibacterial activity of 12-methacryloyloxydodecylpyridinium bromide(MDPB ) might not extend beyond the edges of the bracket; this is a possible limitation of its antibacterial action. The immobilized agent is known to be effective when bacteria contact the surface. This would be beneficial against demineralization under orthodontic brackets from microleakage that can occur after polymerization.

56. Clinical effects of applying different varnishes . An in vivo study found that the use of either fluoride and chlorhexidine varnishes in combination or using a fluoride varnish alone resulted in 30% reduction in WSLs at the time of debonding when compared with a control group that did not receive any varnish applications during treatment . The findings also indicate that on the maxillary incisors, it was observed that only half of them developed WSLs when both varnishes were applied than when only fluoride varnish was used.

57. According to a study by todd and coworkers mean lesion depth in group that was treated with DFR varnish was 50% smaller than the group that was untreated. Schmit and co-workers studied the effect of fluoride varnish DFR on human enamel demineralization adjacent to brackets bonded with a RMGI cement. DFR+ RMGI= lesion depths 50%less Only RMGI= lesion depths 50%less Only DFR= 35% less.

58. Joziak and coworkers reported that DPT fluoride varnish released significantly more fluoride ions into water and was associated with significantly more fluoride uptake in enamel when compared with DFR varnish . Juhlin compared the ability of fluoride varnishes DPT and FP to inhibit enamel demineralization in teeth on which brackets were bonded with composite resin . The mean lesion depth of the FP group was significantly less than the dept of DPT group . Much of the FP varnish remained on the enamel surface at the end of the study, whereas 100 % of the DPT varnish was removed by the 9 th day of the study.

59. Loucks and coworkers compared the ability of FP varnish, Delton (D) sealant and Pro Seal(PS) to resist tooth abrasion and afterward, enamel demineralization from a single 96-hour exposure to a cariogenic solution . FP -47% reduction in lesion depths D-72% reduction PS-92% reduction The lesion detected in the PS group were caused by small air bubbles trapped in the sealant that were exposed by toothbrush abrasion that, in turn, allowed the cariogenic solution to reach the enamel surface.

60. A randomized prospective clinical trial found that varnish FP applied once every 3 months during orthodontic treatment resulted in a 27% reduction in the occurrence of white spot lesions . Repeated applicaton of varnish FP are recommended during treatment, perhaps at each appointment . The most durable material was sealant PS that resisted 2 years of simulated toothbrush wear as well .

61. Remineralization and regression of white spots Clearly the best approach during orthodontic treatment is to prevent lesions from occuring . Once formed, however, many of these early lesions appear to be surface demineralization rather than subsurface lesion with an intact surface zone . Remineralization of these white lesions is a natural phenomenon resulting in the partial reversal of what an early caries lesion is. The mineral of dental enamel is in equilibrium with its environment and saliva contains all the necessary elements for hydroxyapatite crystal growth.

62. In natural state there is demineralization and remineralization continously taking place . Remineralization varies considerably from subject to subject and from site to site in the mouth . Studies have shown that an average remineraliztion takes place about 20% to 30% over 2 weeks . Sometimes the amount of remineralization cannot totally overcome the amount of demineralization even with an effective agent present . Following removal of fixed orthodontic appliance, some regression of postorthodontic lesions is known to occur provided other etiological factors are favorable.

63. Longitudinal measurements of the size of white spot lesions have shown that there was a reduction in the size of the white lesions with time . In a study performed using lesion size as the outcome measure, the mean size at debond was 2.72mm 2 . After 26 weeks the mean size was 1.30mm 2 . In most cases rapid size reduction occurred during the first 12 weeks after appliance removal . Lesion size reduced on average by 1/3 after 12 weeks and ½ by 26 weeks.

64. Ogaard and coworkers warned against treating visible white lesions on the labial surfaces with concentrated fluoride agents, since this arrests both demineralization and remineralization in the lesion by hypermineralization . Instead this workers advocated allowing remineralization by saliva, as this results in greater repair and less visible lesion . The use of high doses of fluoride completely arrests the carious process, which is ideal for posterior carious lesions, but the white spot lesion of orthodontic origin presents a cosmetic challenge and regression is therapeutic goal.

65. If high doses of fluoride are used locally the arrested lesion stays as same size and frequently becomes unsightly and stained with organic debris.

66. Natural remineralization also produces greater resistance to further dissolution due to the fact that during remineralization , components are replaced with less soluble substance that may have larger crystals . This has been reported as plugging of diffusion pathways of enamel by hydroxyapatite crystals as hyper- remineralization . Workers in this field, however have recommended the remineralization of small lesions with low fluoride preparations. They have shown that lesions smaller than 60 μ m deep can be remineralized using these preparations.

67. To avoid arresting the lesion and obtunding the surface layer, several workers have recommended low-dose fluoride applications to enhance subsurface remineralization . Lee linton showed that 50ppm of fluoride mouth rinse had higher efficiency for remineralization than the control solution or a regular mouth rinse containing 250ppm of fluoride . For lesions on surfaces other than on the visible labial surface, application of concentrated fluoride was suggested to prevent further progression . It was suggested that acid etching of the fluoride treated lesions could facilitate remineralization of the lesions by oral fluid.

68. Use of casein phosphopeptitde amorphous calcium phosphate(CPP-ACP ). In 1980s Reynolds drew attention to the fact that casein phosphopeptide amorphous calcium phosphate, which is derived from milk casein was capable of absorbing through the enamel surface and could affect the carious process. CPP-ACP is a delivering system that allows freely available calcium and phosphate ions to attach to enamel and reform into calcium phosphate crystals. The free calcium and phosphate ions move out of the CPP-ACP and into the enamel rods and free form as apatite crystals.

69. A number of different media have been produced to deliver the CPP-ACP , including a water- base mousse, a topical cream, chewing gum, mouth rinses, and sugar free lozenges. The material is marketed under the trade name “ Recaldent .”

70. At present no harmful effect of this material is reported and there is good reason to believe from the invitro reports that remineralization of enamel will provide benefits for the patient suffering from the postorthodontic white spot demineralization.

71. Chewing gum to promote remineralization For sometime, the use of chewing gum has been recommended to assist enamel demineralization . In non-orthodontic patients, a regimen using sorbitol-based chewing gum chewed for 20 mins , 5 times daily for 3 weeks, showed significant remineralization of demineralized enamel when compared with controls without chewing gum . The use of xylitol as an alternative sweetner may be superior when compared with sorbitol because of potential anticaries properties . It is agreed that the beneficial remineralization effects seen is attributable in large measure to salivary stimulation.

72. Microabrasion : If undesirable whitened enamel is still present, the patient parent and dentist need to decide if further esthetic treatment is desired . Whitened enamel that is very apparent compared with the remainder of natural tooth enamel can receive microabrasion treatment . Microabrasion is merely the application of an acidic and abrasive compound to the surface of the enamel . Research indicates that 1 minute application of commercially available microabrasion compounds removes 12 μ m on the first application and 26 μ m on subsequent applications.

73. Removes small amount of surface enamel but leaves a highly polished enamel surface . Abrades surface while compacting calcium and phosphate into interprismatic spaces . Research has demonstrated that although microabrasion removes small amount of enamel surface , the new polished enamel is less suspectible to bacterial colonization and demineralization than natural nonabraded enamel . Following a microabrasion technique, a 4 minute 2% sodium fluoride treatment is recommended . If the microabrasion technique has not achieved optimal esthetics and some whitened enamel is still apparent , vital tooth bleaching can be considered.

74. Vital tooth bleaching: Mild whitened enamel can often be camouflaged by bleaching with standard tray based whitening systems used over-night or with hydrogen peroxide impregnated polyethylene strips.

75. Conclusion Prevention of enamel demineralization during orthodontic treatment is of utmost importance . If enamel demineralization occurs, early diagnosis and intervention is appropriate . Improved brushing with fluoridated dentifrice and over the counter fluoride rinses would be the first recommended intervention . If more aggressive intervention has to be considered due to the extent of demineralized enamel or expected noncompliance with oral hygiene by the patient, professionally applied and/or prescribed fluorides are recommended .

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80. Thank you…..