15. Caton J, Zander HA (1976) Osseous repair of an intrabony pocket without new attachment of connective tissue. J Clin Periodontol 3:54_58

16. Listgarten MA, Rosenberg MM (1979) Histological study of repair following new attachment procedures in human periodontal lesions. J Periodontol 50:333_344

17. Centry IG, Blank LW, Levy BA et al (1997) Carbon dioxide laser for de-epithelization of periodontal flaps. J Periodontol 68(8):763_768

18. Israel M, Rossmann JA, Froum SJ (1995) Use of the carbon dioxide laser in retarding epithelial migration: a pilot histological study utilizing case reports. J Periodontol 66:197_203

19. Kelbauskiene S, Maciulskiene V (2007) A pilot study of Er,Cr:YSGG laser therapy used as an adjunct to scaling and root planing in patients with early and moderate periodontitis. Stomatologija 9(1):21_26

20. Nyman S, Gottlow J, Karring T et al (1982) The regenerative potential of the periodontal ligament: an experimental study in monkeys. J Clin Periodontol 9:257

21. Nyman S, Lindhe J, Karring T et al (1982) New attachment following surgical treatment of human periodontal disease. J Clin Periodontol 9:290

22. Loe H, Silness J (1963) Periodontal disease in pregnancy. Prevalence and severity. Acta Odontol Scand 21:553_551

23.Melcher AH (1976) On the repair potential of periodontal tissues. J Periodontol 47(5):256_260

24. Melcher AH, Mcculloch CAG, Cheong T et al (1987) Cells from bone synthesize cementum-like and bone-like tissue in vitro and may migrate into periodontal ligament in vivo. J Periodontal Res 22:246_247

25. Shulean A, Schwarz F, Berakdar M et al (2004) Periodontal treatment with an Er:YAG laser compared to ultrasonic instrumentation: a pilot study. J Periodontol 75:966_973

26. Schwarrz F, Berakdar M, Georg T et al (2003) Clinical evaluation of an Er:YAG laser combined with scaling and root planing for non-surgical periodontal treatment. J Clin Periodontol 30:26_34

27. Crespi R, Cappare P, Toscanelli I, Gherlone E et al (2007) Effects of Er:YAG laser compared to ultrasonic scaler in periodontal treatment: a 2-year follow-up split mouth clinical study. J Periodontol 78:1195_1200

28.Schwarz F, Berakdar M, Georg T, Reich E et al (2003) Clinical evaluation of an Er:YAG laser combined with scaling and root planing for non-surgical periodontal treatment. J Clin Periodontol 30:26_34

29. Blomlof JP, Blomlof LB, Lindskog SF (1996) Smear removal and collagen exposure after non-surgical root planing followed by etching with an EDTA gel preparation. J Periodontol 67(9):841_845

30. Polson AM, Frederich GT, Ladenheim S, Hanes PJ (1984) The production of a root surface smear layer by instrumentation and its removal by citric acid. J Periodontol 55:443_446

31.Crespi R, Romanos GE, Cassinelli C, Gherlone E (2006) Effects of Er:YAG laser and ultrasonic system on fibroblast attachment to root surfaces: in vitro study. J Periodontol 77:1217_1222

32. Schwarz F, Shulean A, Georg T, Reich E (2001) Periodontal treatment with an Er:YAG laser compared to scaling and root planing. A controlled clinical study. J Periodontol 72:361_368

33.Folwaczny M, Aggsataller H, Mehl A, Hickel R (2003) Removal of bacterial endotoxin from root surface with Er:YAG laser. Am J Dent 16:3_5

34. Renvert S, Wikstrom M, Dahlen G, Slots J et al (1990) Effect of root debridement on the elimination of Actinobacillus actinomycetemcomitans. J Clin Periodontol 17:345_350

35. Takamatsu N, Yano K, He T, Umeda M et al (1999) Effect of initial periodontal therapy on the frequency of detecting Bacteroides forsythus, Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans. J Periodontol 70:574_580

36. Centty I, Blank L, Levy B et al (1997) Carbon dioxide laser for de-epithelization of periodontal flaps. J Periodontol 763_768

 

One-year clinical results of Er,Cr:YSGG laser application in addition to scaling and root planing in patients with early to moderate periodontitis

 

Solveiga Kelbauskiene, DDS,1* Nomeda Baseviciene, DDS, PhD,1Kawe Goharkhay, MD, DMD2, Andreas Moritz, MD,DMD, PhD2, Vita Machiulskiene DDS, PhD1

 

1Clinic of Dental and Oral Pathology, Faculty of Odontology,Kaunas University of Medicine, Kaunas, Lithuania

2Department of Conservative Dentistry, Bernhard Gottlieb University Clinic of Dentistry, Medical University of Vienna, Austria

 

 

 

*Correspondence to: Dr. Solveiga Kelbauskiene, DDS, PhD student, Clinic of Dental and Oral Pathology, Kaunas University of Medicine, Eiveniu 2, Kaunas, Lithuania.

E-mail: skelbauskiene@gmail.com

  Abstract

In 30 patients with periodontitis, a total of 278 teeth exhibiting bleeding on probing, subgingival calculus and a probing depth more than 3mm, were examined. For every participant, two treatment types were alternatively applied on the contralateral quadrants: scaling and root planing (SRP) as control, and SRP followed by Er;Cr:YSGG laser application (SRP+laser), as a test method. Five clinical parameters: plaque level, bleeding on probing, probing depth, gingival recession and clinical attachment level were examined at baseline and at 2,3,6,12 months after treatment. Of the total of 1668 sites examined in all patients, 1088 sites were found with a probing depth >3mm. In these sites, differences in clinical parameters between “SRP” and “SRP+laser” treated quadrants were analyzed, assuming the level of p < 0.05 as significant. After two months from baseline, the mean probing depth reduction and the clinical attachment level gain were significantly greater in “SRP+laser” than in “SRP” quadrants, and remained so throughout the study (p<0.001). A marked reduction of the bleeding scores occurred in all examined sites, irrespectively of the treatment method. However, after 12 months, significantly less teeth exhibited bleeding on probing in “SRP+laser” quadrants than in “SRP” quadrants (p<0.001). The mean plaque and gingival recession levels did not differ between the “SRP” and “SRP+laser” quadrants neither before nor after the treatment.

The periodontal procedures either using Er;Cr:YSGG laser after SRP or, SRP alone, lead to significant improvements in all clinical parameters investigated. However, laser application as an adjunct to SRP, appeared to be more advantageous.

Key words: Er;Cr:YSGG laser, scaling and root planing,clinical attachment level

 

 INTRODUCTION

Chronic periodontitis is an infectious disease, related to inflammation of the supporting tissues of teeth, and to the following progressive loss of attachment and of the bone. The primary goal in treatment of  periodontitis is removal of subgingival deposits, bacterial biofilm and smear layer, in order to prevent progression of the disease [1, 2]. This treatment strategy aims to restore the periodontal attachment level so that the periodontal fibers could connect into newly formed cementum [3].

Conventional periodontal procedures, otherwise called as scaling and root planing, consist of debridement of the contaminated root surfaces as well as of elimination of bacteria and their endotoxins from the cementum and  from the adjacent periodontal tissues [4]. However, removal of calculus by means of manual instruments and ultrasonic scalers is often incomplete, due to the root topography, painful and rather time consuming [5]. In cases, where gingival recession exists, opened root surfaces may remain sensitive after the procedure. Furthermore, such mechanical treatment usually produces a smear layer and deep grooves on the root surfaces, that may adversely affect healing of the periodontal tissue [6]. Considering these disadvantages, in recent years lasers were suggested as an alternative for treatment of periodontitis.Lasers are designed to ablate or, to  vaporize only the diseased tissue from the inner epithelial lining of a periodontal pocket resulting in a better, more predictable end result to treatment, by cauterizing  blood vessels, nerve endings and lymph glands, providing hemostasis, post operative pain control and rapid healing [7].

 However, due to the complex structure of periodontium (combination of gingiva, periodontal ligament, cementum and alveolar bone) the use of lasers for periodontal treatment can be rather problematic. As concluded by several researchers, neither CO2, nor Nd:YAG or diode lasers are effective in removing calculus from the root surfaces [7]. When these lasers were used directly on the cementum or on the alveolar bone, thermal side effects, such as carbonization, melting had been reported [8].

Recently, Er:YAG ( erbium- doped:yttrium, aluminium and garnet, wavelength 2940 nm) and the Er,Cr:YSGG (Erbium-Chromium-Yttrium-Scallium-Gallium-Garnet, wavelength 2790 nm) lasers were introduced. Several studies suggested that Erbium lasers could effectively remove calculus [9,10] as well as superficial layers of the contaminated cementum and exhibit high bactericidal effects [11,12] without any thermal damage to the root surface or, to the adjacent tissue [13,14].

The most common mechanism of periodontal wound healing is characterized by the epithelization of the internal surface of the flap in contact with the root cementum, forming so called long epithelial attachment [15, 16]. The epithelial tissue possesses migrating cells that are able to invade the periodontal wound area faster than other cells, and to facilitate periodontal re-attachment. Therefore, it was proposed to increase the distance for the epithelial cells to travel, in order to allow the periodontal ligament cells to reach the radicular surface first. By means of a laser, it is possible to de-epithelize the flap and thus, to delay epithelial migration.Consecutively, formation of the connective tissue and new alveolar bone is facilitated [17, 18].These processes are expected to improve clinical parameters in periodontal treatment.

The purpose of this study was to compare the clinical results of  conventional scaling and root planing with a therapy using  Er;Cr:YSGG laser in adjunct to scaling and root planing, during one year of application, in patients with early to moderate periodontitis.

 

 

MATERIALS AND METHODS

The study was conducted at Clinic of Dental and Oral Pathology, Kaunas University of Medicine, during the period from March 2006 to March 2008. The study protocol was approved by the Ethical Committee of Kaunas University of Medicine, Lithuania.

Selection of subjects: The study subjects were selected from the patients applying for periodontal treatment at the University Clinic. Patient’s selection was based on the signed informed consent forms, and according to the following criteria: 

  • No periodontal treatment received within the last 12 months
  • No systemic diseases, that could potentially influence the outcome of the therapy (diabetes, immune deficiencies, cancer, haemorragic disorders, epilepsy etc)
  • No use of systemic antibiotics at least 6 months prior to,duringand 12 months after the treatment
  • Non smokers
  • No pregnancy

Thus, a total of 30 patients with the diagnosis of early or moderate periodontitis, between 26 and 58 years of age (16 men, 14 women) were included in the study.

 

Study design: the study was performed according to a split-mouth design, on single-rooted teeth (lower or upper incisors and canines, upper second premolars, lower first and second premolars).  A total of 278 teeth (123 in the maxilla, and 155 in themandible) exhibiting  gingival inflammation with positive bleeding on probing (BOP), subgingival calculus and a PD (probing depth) more than 3 mm  on at least one site of the tooth  were selected for examination. Of the total of 1668 sites examined, 1088 sites exhibited the probing depth more than 3 mm (range: >3 mm to 6 mm).  A detailed description of the study material is presented in Figure 1.

Two types of treatment were performed for the study participants:

1. Conventional scaling and root planing (SRP) – ‘control’ group

2. Er;Cr;YSGG laser application, in addition to conventional scaling and root planing (SRP+ laser) – ‘test’ group

Every participant received both types of treatment using different mouth quadrants, for at least, two quadrants. On one side, the teeth were treated by scaling and root planing only (control method, SRP), whereas the teeth of the contra-lateral side were treated by Er;Cr:YSGG laser immediately after SRP (test method, SRP+laser). Selection of the mouth quadrants to be treated with either test, or control method, was performed randomly (for details, see Kelbauskiene, Maciulskiene, 2006)[19].  The selected treatment protocols were coded in the patients’ case descriptions, in order to prevent biased measurements of the treatment outcomes. Two weeks prior to  treatment, all patients were scheduled for oral hygiene instructions as well as for professional supra-gingival tooth cleaning according to individual needs.  The same oral hygiene procedures were performed after 3 and 6 months.

The baseline recordings of the clinical parameters and the following treatment procedures were performed by a periodontist (SK), who was unaware of the quadrants’ allocation to be treated by the test method or by the control method. The clinical parameters of periodontal status 2, 3, 6 and 12 months after the treatment were measured by another examiner, who didn’t know what quadrant was treated by SRP alone or, by SRP+laser.

The probing measurements were taken after the recording of plaque and of the bleeding scores.

  All periodontal treatment procedures were performed under standardized conditions by the same operator (SK).

For all patients, in the control quadrants scaling and root planing was performed immediately after the baseline examination, and subsequently, supra-gingival scaling and polishing was repeated 3 and 6 months after the initial treatment.

In the test quadrants SRP+laser was performed immediately after the baseline examination. Only supra-gingival scaling and polishing was repeated 3 and 6 months after the initial treatment.

Scaling and root planing (SRP): subgingival instrumentation of the root surfaces was performed using an ultrasonic scaler ( Satelec, Acteon, Switzerland) with a sharp-pointed tip. The ultrasonic scaler was conducted by contacting the probe obliquely to the root surface at an angle of approximately 15 degrees and moving the tip in a sweeping motion. The instrumentation was accomplished using Gracey curettes (American Eagle, USA). The procedure was finished until the operator felt that the root surfaces were adequately scaled and planed.

Er, Cr: YSGG laser application after SRP (SRP+laser): An Er, Cr: YSGG laser device(Waterlase, Biolase, USA)was used in this study. This laser system emits photons at a wavelength of 2.78 µm and has a pulse duration of 140 to 200 µs with the repetition rate of 20 Hz. The average power output can vary from 0 to 6 W. A Z-6 series tip of 600 µm in diameter and 9 mm in length, was used to remove the inner epithelial lining (the epithelium inside the periodontal pocket) to the depth of the pocket, and 5mm of the outer epithelium (oral epithelium near the free gingival margin). This technique allows cells that arise from periodontal ligament and the bone, to repopulate the root surface, while excluding epithelial and gingival cells from the initial wound healing [20,21]. A 9 mm Z-6tip marked to the depth of the pocket was used at a setting of 1W, 10% air and 15% water. The treatment was performed from coronal to apical paths parallel to the long axis to the root surfaces. To condition the root the laser tip was angled 5-15 degrees toward the root and moved up and down until the root surface was left with an acid-etched appearance. The same procedure was performed once a week for each mm of pocket reduction desired to obtain normal probing depth of 3 mm or less. This required an average of 3 appointments. At subsequent visits, inner epithelium to the depth of the pocket (1mm less than at the previous appointment) and 5mm of the outer epithelium was removed.

Clinical measurements and data collection: The following parameters were recorded before the treatment, and 2, 3, 6, 12 months after the treatment: plaque index (PI), bleeding on probing (BOP), probing depth (PD) and clinical attachment level (CAL).

Plaque index was assessed for every tooth examined using the following scale modified from Silness & Löe [22]: 0 – no plaque; 1 – plaque detected by probe only; 2 – visible, average amount of plaque; 3 – a lot of visible plaque near the gingival margin and into the pocket.

Bleeding on probing was assessed simultaneously to the pocket measurements, and the absence or presence of bleeding up to 30 seconds after probing was recorded. Probing depth (PD) was measured from the gingival margin to the depth of the pocket.

Clinical attachment level (CAL) was measured from the CEJ ( cementum-enamel junction) to the bottom of the probable sulcus.

The measurements were made at six sites per tooth: mesio-vestibular (mv), mid-vestibular (v), disto-vestibular (dv), mesio-lingual (ml), mid-lingual (l), disto-lingual (dl) using a manual periodontal probe (PCP 12, Hu-Friedy).

Statistical analysis: The data were analyzed using SPSS 13.0 (SPSS inc., Chicago III) statistical package. Statistical significance of difference in proportion was tested by chi square test. The mean values, and standard deviations of the clinical parameters were calculated. Statistical testing between the groups (“SRP” and SRP+laser”) for differences of GR ( gingival recession), PD as well as of CAL were assessed by comparing the mean change values estimated for all tooth aspects, in the sites with baseline PD >3mm,  at different time points. The evaluation of mean values was performed using Student's t test. For the data that were not normally distributed, as shown by a Kolmogorov-Smirnov test, Mann-Whitney U test was applied. For testing the measurements of dependent variables, the paired t-test for the continuous data, and Wilcoxon’stest for the ordinal data were used. The difference with significance level below 0.05 was evaluated as significant.

 The power of the study, given PD of 1mm as a significant difference between the groups, was calculated to be 0.99 which justified the sample size of 30 patients.

 Plaque distribution was evaluated at a tooth level, and was determined by percentages of teeth with different scores recorded. Score 0 and score 1 were added together and were defined as “no plaque”, score 2 and score 3 were added together and defined as “visible plaque”. Plaques levels were estimated in percentages of teeth presenting scores with “visible plaque”.

Changes in BOP were expressed as percentages of presence or absence of bleeding up to 30 s after probing was recorded.

Inter-examiner and intra-examiner reproducibility testing: four patients, everyone presenting two pairs of contra-lateral teeth with the probing depth ≥4 mm on at least one aspect of the tooth, were examined twice, with an interval of 48 hours to calibrate gingival recession and probing depth. Variation between the repeated measurements not exceeding 1 mm was accepted. Reproducibility testing was performed using a manual periodontal probe (PCP 12, Hu-Friedy).

The percentages of inter-examiner and intra-examiner agreements were 93, 8% and 90%, respectively. 

 

RESULTS

Baseline clinical examination of the patients revealed no statistically significant differences in the investigated parameters between “SRP” and SRP+laser” treated quadrants. However, in the sites with baseline PD > 3 mm, the baseline mean PD and mean CAL values were significantly higher in the “SRP+laser” quadrants as compared to “SRP’ quadrants (Table 1).

During the entire study period, the status of oral hygiene remained good in all patients. No statistically significant differences in PI values were observed between the “SRP” treated and “SRP+laser” treated quadrants neither before nor after the instrumentation. The percentage of teeth presenting “visible plaque”  increased in all treated quadrants, when estimated 2 and 3 months after the instrumentation (also 6 months after the treatment, in the “SRP ” quadrants), however, they were not different  significantly from the baseline plaque levels  when estimated 12 months after the instrumentation (Figure 2).  

The changes in bleeding on probing (BOP) levels during the study period are presented in Figure 3.  At baseline, 79.0% of the teeth examined in the “SRP+laser“- treated quadrants, and 74.1% of the teeth examined in the “SRP”- treated quadrants, exhibited bleeding on probing.  After the instrumentation,a marked  reduction of the bleeding scores occurred in all examined sites treated with either ‘SRP’ or, ‘SRP+laser’ method (Figure 3). However, at the final examination after 12 months,   significantly less teeth exhibited BOP in the “SRP+laser”- treated quadrants than in the “SRP”- treated quadrants:  9.8% and 26.7%, respectively (p<0.001).

The mean values of gingival recession (GR) for the investigated tooth sites at baseline did not differ between “SRP”- treated and “SRP+laser”- treated quadrants. The estimated changes of gingival recession were marginal and remained similar between ‘SRP’ and ‘SRP+laser’ quadrants through the entire study period (Table 1).  The mean PD changes from baseline values, estimated at all following examination time points (2-, 3-,6-,12 months) after the instrumentation, differed significantly between “SRP”- treated and “SRP+laser”- treated quadrants, the mean PD reduction being greater  for the “SRP+laser”- treated sites than for the sites treated by SRP alone (p<0,001)(Table 2). The same tendency was observed regarding CAL measurements: statistically significant differences of CAL gain (p<0,001) were found between “SRP treated” and “SRP+laser”- treated quadrants at 2-, 3-,6-,12 months examination points, the CAL gain being greater in “SRP+laser”- treated sites (Table1).

When CAL changes were analyzed for the lingual and vestibular surfaces separately, the same tendency was observed as for all tooth aspects: the significantly greater attachment gain was estimated in “SRP+laser” treated lingual and vestibular sites as compared to “SRP” treated sites, thorough the entire study period ( Figure 4). 

 

 

DISCUSSION

The explanation of periodontal healing is largely based on Melcher’s hypothesis [ 23], which suggests that formation of attachment between the tooth and the periodontal tissue depends on the origin of the cells repopulating the wound area, and that the only cells able to  achieve true  periodontal regeneration are periodontal ligament cells (‘pdl’) [24]. For new attachment to form, the epithelium  within  the periodontal  pocket needs to be removed, otherwise the epithelial cells would inhibit proliferation as well as migration of ‘pdl’ cells from the periodontal space to the wound area. As soon as ‘pdl’ cells reach the root surface, they start to stimulate cementoblasts to form the new cementum, and  mediate  the  attachment  of  the  connective  tissue  and  the bone  to  this cementum . Thus, the major advantage of laser application as compared to other treatment methods such as conventional scaling and root planing is thought to be the facilitated  process of epithelium removal from the periodontal pockets.

 The results of the present study have demonstrated that non- surgical periodontal treatment with either combination of a laser and SRP,  or root scaling and planing alone lead to clinically and statistically significant improvements in all investigated parameters at 2, 3, 6, and 12 months following the treatment. The observation that in all cases there were no post-operative complications indicates good tolerance of all conservative treatment procedures received.

 

However, the use of the Er,Cr:YSGG laser in addition to scaling and root planing, resulted in a statistically significant and consistently greater reduction of the probing depth and gain of the clinical attachment level when compared to the results of SRP alone. These results are in agreement with other studies [25, 27] where a significant PD reduction and CAL gain was achieved after the subgingival debridement procedures with an Er:YAG laser [26]. Thus, it has been suggested that Er:YAG laser could be considered as a meaningful alternative to hand instruments in treatment of periodontitis [12].

 According to our results, the most obvious changes of the periodontal depth  in”SRP” and “SRP+laser” treated quadrants were achieved in 6 months after the treatment ( Table 1). However, after 12 months, the estimated mean PD reduction values decreased significantly in both treatment groups when compared to the mean PD reduction values estimated after 6 months from baseline. It appeared that in the “SRP” treated quadrants the mean PD value after 12 months was still lower than the respective baseline value, but became indicative for early periodontitis (mean PD > 3 mm: 4.07 (0.79) – 0.89  (1.04)= 3.19 (1.03), Table 1). However, such tendency was not observed in “SRP+laser” treated quadrants (4.33 (1.08) - 1.71 (1.35) =2.62 (1.17), Table 1). Considering the fact that at baseline the mean estimated PD values in “SRP” quadrants were even lower than in the “SRP+laser” quadrants, the obtained results suggest that a combined SRP and laser therapy provides better longitudinal results than SRP alone. The observation of the decreased PD reduction in “SRP” treated quadrants over time can potentially explain the increase of  BOP values in these quadrants, in 12 months after the treatment.

 In the present study values of the plaque values (PI) increased in both treatment groups  3  months after treatment comparing with baseline (p<0.05), although there were no significant differences between groups through the whole study.. The potential explanation for this could be, that supragingival professional teeth cleaning was performed just two weeks before baseline examination and there was no professional hygiene visit between the baseline appointment and the 3 month follow-up visit. Consequently, the amount of plaque present was dependent completely on the patients' home care compliance.   

Blomlof et al [29] showed that ultrasonic debridement resulted in a smooth surface covered by a smear layer, whereas the Er:YAG laser induced glazed microstructures presenting a relative rough surface topography. A smear layer, which contains bacteria and inflammatory substances, may adversely affect the healing of periodontal tissue [30]. Crespi et al [31] reported that Er.YAG treated root surfaces that were roughened promoted fibroblast attachment and contributed to a significant gain of clinical attachment level. Removal of the smear layer and etching of the root surface could explain the increased fibroblast attachment, which might be a partial explanation for the improved probing depth and clinical attachment level.

Findings from several studies reported a high bactericidal potential of Er:YAG laser [12, 32]. In addition, besides viable bacteria, laser radiation was capable to remove endotoxins from the root surfaces [33]. Mechanical periodontal treatment alone usually improves clinical conditions; however, it is not effective to eliminate all types of bacteria [34, 35].  Furthermore, the literature suggests that laser application helps to remove sulcular epithelium more precisely and effectively than the manual instruments; without causing underlying damage to the connective tissue [36]. Consequently, laser de-epithelization blocks the down-growth of epithelium into the healing periodontal pocket, allows cells to arise from the periodontal ligament and so enhances periodontal reattachment [18].

Schwarz et al [26] compared the use of an Er:YAG laser + SRP with the application of laser alone, in a split-mouth design for treatmen