Acoustic microstreaming: detection and measurement around ultrasonic scalers

In Vitro Evaluation of Direct and Indirect Effects of Sonic and Ultrasonic Instrumentations on the Shear Bond Strength of Orthodontic Brackets

Objective

Sonic and ultrasonic instrumentations generate vibrations that may influence debonding characteristics. The objective of this in vitro study was to assess the direct and indirect effects of sonic and ultrasonic periodontal instrumentations on the shear bond strength (SBS) and the adhesive remnant index (ARI) scores of metallic orthodontic brackets.

Methods

Metallic brackets were bonded to 75 extracted mandibular central incisors that were embedded in acrylic resin. Instrumentations around the bracket base performed with ultrasonic (UltrasonicB group, n=15) and sonic (SonicB group, n=15) scalers were used to evaluate the direct effects on the SBS of brackets. Lingual surface instrumentations with ultrasonic (UltrasonicL group, n=15) and sonic (SonicL group, n=15) scalers were performed to assess the indirect effects. The control group (n=15) did not have any treatment. Instrumentations were performed for 30 s with 0° scaler tip angulations with settings recommended by manufacturers. The SBS of the brackets tested with a universal testing machine and ARI scores were recorded. Data were analyzed by Kruskal-Wallis and Mann-Whitney U tests.

Results

The mean SBS of the control group was significantly higher than that of the UltrasonicB and SonicB groups (p=0.008). The UltrasonicL and SonicL group instrumentations also decreased the SBS, although the difference was statistically insignificant. UltrasonicB instrumentations caused significantly higher frequency of ARI scores than the control group.

Conclusion

The decrease of the SBS of metallic brackets indicates the influence of ultrasonic and sonic instrumentations on the breakage behavior at the bracket-resin interface. Instrumentations around the bracket base should be conducted with caution to decrease the bond failure risk of metallic brackets.

Evaluation of the Effects of Er,Cr:YSGG Laser, Ultrasonic Scaler and Curette on Root Surface Profile Using Surface Analyser and Scanning Electron Microscope: An In Vitro Study

Introduction: The periodontal therapy is primarily targeted at removal of dental plaque and plaque retentive factors. Although the thorough removal of adherent plaque, calculus and infected root cementum is desirable, it is not always achieved by conventional modalities. To accomplish more efficient results several alternative devices have been used. Lasers are one of the most promising modalities for nonsurgical periodontal treatment as they can achieve excellent tissue ablation with strong bactericidal and detoxification effects. Methods: Thirty freshly extracted premolars were selected and decoronated. The mesial surface of each root was divided vertically into four approximately equal parts. These were distributed into four group based on the root surface treatment. Part A (n = 30) was taken as control and no instrumentation was performed. Part B (n = 30) was irradiated by Erbium, Chromium doped Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) laser. Part C (n = 30) was treated by piezoelectric ultrasonic scaler. Part D (n = 30) was treated by Gracey curette. The surface roughness was quantitatively analyzed by profilometer using roughness average (Ra) value, while presence of smear layer, cracks, craters and melting of surface were analyzed using scanning electron microscope (SEM). The means across the groups were statistically compared with control using Dunnett test. Results: Among the test groups, Er,Cr:YSGG laser group showed maximum surface roughness (mean Ra value of 4.14 μm) as compared to ultrasonic scaler (1.727 μm) and curette group (1.22 μm). However, surface with smear layer were found to be maximum (50%) in curette treated samples and minimum (20%) in laser treated ones. Maximum cracks (83.34%) were produced by ultrasonic scaler, and minimum (43.33%) by curettes. Crater formation was maximum (50%) in laser treated samples and minimum (3.33%) in curette treated ones. 63.33% samples treated by laser demonstrated melting of root surface, followed by ultrasonic scaler and curettes. Conclusion: Er,Cr:YSGG laser produced maximum microstructural changes on root surface that can influence the attachment of soft periodontal tissues as well as plaque and calculus deposition. In vivo studies are needed to validate these results and to evaluate their clinical effects.

Penetration of sub-micron particles into dentinal tubules using ultrasonic cavitation

OBJECTIVES

Functionalised silica sub-micron particles are being investigated as a method of delivering antimicrobials and remineralisation agents into dentinal tubules. However, their methods of application are not optimised, resulting in shallow penetration and aggregation. The aim of this study is to investigate the impact of cavitation occurring around ultrasonic scalers for enhancing particle penetration into dentinal tubules.

METHODS

Dentine slices were prepared from premolar teeth. Silica sub-micron particles were prepared in water or acetone. Cavitation from an ultrasonic scaler (Satelec P5 Newtron, Acteon, France) was applied to dentine slices immersed inside the sub-micron particle solutions. Samples were imaged with scanning electron microscopy (SEM) to assess tubule occlusion and particle penetration.

RESULTS

Qualitative observations of SEM images showed some tubule occlusion. The particles could penetrate inside the tubules up to 60μm when there was no cavitation and up to ∼180μm when there was cavitation.

CONCLUSIONS

The cavitation bubbles produced from an ultrasonic scaler may be used to deliver sub-micron particles into dentine. This method has the potential to deliver such particles deeper into the dentinal tubules.

CLINICAL SIGNIFICANCE

Cavitation from a clinical ultrasonic scaler may enhance penetration of sub-micron particles into dentinal tubules. This can aid in the development of novel methods for delivering therapeutic clinical materials for hypersensitivity relief and treatment of dentinal caries.

Periodontal therapy -- an adjuvant for glycemic control

AIMS

Periodontitis is an oral infection affecting the tooth- supporting tissues. Although the prime etiology for this condition is bacterial plaque, the host immune response also has substantial contribution to the destruction of the periodontal apparatus. Periodontitis elicits a "low grade systemic inflammation". Diabetes mellitus is intricately related to the development, progression and severity of periodontitis. The literature is abundant with studies depicting this association. Periodontal therapy (PT) involves removal of bacterial component leading to the resolution of clinical signs and symptoms of disease. This review aims to create awareness amongst the medical professionals regarding the two-way relationship between diabetes and periodontitis, emphasizing on the positive effects of PT.

MATERIAL AND METHODS

Studies addressing the effects of PT on glycemic control in type 2 Diabetes (T2DM) subjects were identified using PubMed search with key search terms such as "Glycemic control", "Periodontitis", "Periodontal therapy", "Type 2 diabetes mellitus". The review has been prepared by screening PUBMED database from January 1990 to March 2012.

RESULTS

PT bears an unexplored potential and can serve as an adjuvant to the conventional treatment for diabetes.

CONCLUSION

A major conclusion of this review is that PT instituted in type 2 diabetic human subjects assists in amelioration of the inflammatory biomarker levels and glycemic status. There is a wide scope for further studies to highlight the beneficial effects of PT in diabetic subjects and the dire need for periodontal screening of these individuals for glycemic maintenance.

Er:YAG laser treatment in supportive periodontal therapy

OBJECTIVE

To assess clinical and microbiological outcomes of an Er:YAG laser in comparison with sonic debridement in the treatment of persistent periodontal pockets in a prospective randomized controlled multicentre study design.

MATERIAL AND METHODS

A total of 78 patients in supportive periodontal therapy with two residual pockets were included, 58 were available for the whole follow-up period. Root surfaces were instrumented either with a sonic scaler (Sonicflex(®) 2003 L) or with an Er:YAG laser (KEY Laser(®) 3). Clinical attachment levels (CAL), Probing depths (PD), Plaque control record (PCR) and Bleeding on probing (BOP) were assessed at baseline, 13 and 26 weeks after treatment. In addition, microbiological analysis was performed employing a DNA diagnostic test kit (micro-IDent(®) Plus).

RESULTS

Probing depths and CAL were significantly reduced in both groups over time (p < 0.05), without significant differences between the groups (p > 0.05). BOP frequency values decreased significantly within both groups (p < 0.05), with no difference between the laser and the sonic treatment (p > 0.05). PCR frequency values did not change during the observation period (p > 0.05). Microbiological analysis failed to expose any significant difference based on treatment group or period.

CONCLUSION

Employing both sonic and laser treatment procedures during supportive periodontal care, similar clinical and microbiological outcomes can be expected.

The effect of the Vector scaler system on human teeth: a systematic review

AIM

To review the available literature, considering the effect of instrumentation with the Vector ultrasonic scaler on human teeth in vitro and in vivo compared to conventional ultrasonic instruments and/or hand instrumentation. The assessed effects are calculus removal, time of instrumentation, root surface aspects, cell attachment, patients' perception, bleeding upon probing, pocket depth, clinical attachment loss and microbiological effects.

MATERIALS AND METHODS

MEDLINE-PubMed and the Cochrane Central register of controlled trials (CENTRAL) were searched up through January 2008 to identify appropriate studies.

RESULTS

Independent screening of the titles and abstracts of 270 MEDLINE-PubMed and 15 Cochrane papers resulted in 15 suitable publications. The studies differed in design and outcome, so this review summarizes the outcomes in a descriptive manner. Comparisons are presented against conventional ultrasonic system and scaling and root planing.

CONCLUSION

The Vector ultrasonic scaler provided comparable clinical and microbiological periodontal healing results as scaling and root planing and conventional ultrasonic system in moderately deep pockets. The Vector ultrasonic scaler may be used as a gentle root debridement device for supportive periodontal therapy, as an alternative to other conventional ultrasonic system. The operator should however consider the extra time needed for instrumentation.

Application of ultrasound in periodontics: Part I

Ultrasonic is a branch of acoustics concerned with sound vibrations in frequency ranges above audible level. Ultrasound uses the transmission and reflection of acoustic energy. A pulse is propagated and its reflection is received, both by the transducer. For clinical purposes ultrasound is generated by transducers, which converts electrical energy into ultrasonic waves. This is usually achieved by magnetostriction or piezoelectricity. Primary effects of ultrasound are thermal, mechanical (cavitation and microstreaming), and chemical (sonochemicals). Knowledge of the basic and other secondary effects of ultrasound is essential for the development of techniques of application.

Microbiological findings after periodontal therapy using curettes, Er:YAG laser, sonic, and ultrasonic scalers

AIM

To evaluate and compare the microbiological effects of hand instruments, Er:YAG-laser, sonic, and ultrasonic scalers in patients with chronic periodontitis. Patient perception of each treatment was documented.

MATERIAL AND METHODS

From 72 patients, bacterial samples were collected from the deepest pocket in each quadrant (total: 288 sites). A polymerase chain reaction kit estimated the amount of Aggregatibacter (Actinobacillus) actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Tannerella forsythensis (Tf), and Treponema denticola (Td) at baseline as well as 3 and 6 months after therapy. One quadrant in each patient was randomly assigned to curettes (H-group), Er:YAG laser (L-group), sonic device (S-group), or ultrasonic device (U-group).

RESULTS

Three months post-operatively, the amounts of Pg, Pi, Tf, and Td were significantly reduced in all groups. Laser and sonic instrumentation failed to reduce Aa. Six months after therapy, significant differences were still detected for Pg (L- and U-group), for Pi and Tf (S-group), and for Td (L-, S- and U-group). Patients rated ultrasonic treatment as more preferable than hand and laser instrumentation.

CONCLUSION

The various treatment methods resulted in a comparable reduction of the evaluated periodontal pathogens, and bacterial increase was only partially different 6 months post-operatively. Ultrasonic instrumentation caused less discomfort.

Subjective intensity of pain during ultrasonic supragingival calculus removal

OBJECTIVE

To assess subjective intensities of pain during supragingival calculus removal employing ultrasonic scaler tips of two different shapes.

MATERIAL AND METHODS

Twenty patients were treated using a piezoelectric ultrasonic device (Sirosonic L) and two different scaler tips representing a conventional (Instrument No. 3) and a slim-line style (Perio Pro Line Instrument SI-11) in a split-mouth design. Pain was recorded during calculus removal at intervals of 0.5 s employing an inter-modal intensity comparison. Additionally, a visual analogue scale was used for evaluation directly after the treatment procedure. Treatment time was recorded to assess the efficiency of calculus removal.

RESULTS

Pain assessment during treatment showed that the slim-line scaler tip (median pain score: 1.4 [U], maximum: 3.5 [U], minimum: 0 [U]) caused less pain than the conventional device (median pain score: 7.8 [U], maximum: 14.7 [U], minimum: 0 [U]) (p<0.05). These results could be confirmed by the visual analogue scale. Treatment with the slim-line tip took significantly longer than treatment with the conventional tip (p<0.05).

CONCLUSIONS

Using slim-line-styled ultrasonic scaler tips for supragingival calculus removal, painful sensations can be reduced compared with conventional ultrasonic devices. Thus, it might be possible to increase the patient's compliance during dental treatment with oscillating instruments.

Periodontal healing after non-surgical therapy with a new ultrasonic device: a randomized controlled clinical trial

AIM

The aim of this study was to compare the clinical and microbiological healing outcomes following non-surgical periodontal therapy using the new Vector ultrasonic system versus scaling and root planing (S/RP) with Gracey curettes.

MATERIAL AND METHODS

The study comprised 20 chronic periodontitis patients. Using a split-mouth design, both treatment modalities were randomly applied to one quadrant of the upper and the lower jaws each. Clinical and microbiological parameters were assessed at baseline, 4 weeks, and 6 months after treatment. Furthermore, post-operative hypersensitivity was assessed. The Wilcoxon signed rank test (alpha=0.05) was used for statistical analysis.

RESULTS

Both therapies provided statistically significant clinical and microbiological improvements of periodontal conditions after 4 weeks and 6 months. Hypersensitive teeth were found only 4 weeks after S/RP. Besides a significantly better bleeding on probing reduction in deep S/RP sites, no other clinical and microbiological parameters revealed significant differences between the sites treated with the Vector system or S/RP.

CONCLUSION

Both the Vector system and S/RP provided favourable periodontal healing results, although in deep pockets S/RP appeared to achieve a better resolution of inflammation.

Sonic and ultrasonic scalers in periodontal treatment: a review

Periodontal therapy aims at arresting periodontal infection and maintaining a healthy periodontium. The periodic mechanical removal of subgingival microbial biofilms is essential for controlling inflammatory periodontal disease. Mechanical periodontal therapy consists of scaling, root planing and gingival curettage. The sonic and ultrasonic scalers are valuable tools in the prevention of periodontal disease. The vibration of scaler tips is the main effect to remove the deposits from the dental surface, such as bacterial plaque, calculus and endotoxin. However, constant flushing activity of the lavage used to cool the tips and cavitational activity result in disruption of the weak and unattached subgingival plaque. The aim of the study was to review the safety, efficacy, role and deleterious side-effects of sonic and ultrasonic scalers in mechanical periodontal therapy.

Efficiency of the VectorTM-system compared with conventional subgingival debridement in vitro and in vivo

OBJECTIVE

To assess the efficacy of the novel ultrasonic Vector -system system for subgingival debridement and to compare the results with conventional periodontal instrumentation in vitro and in vivo.

MATERIAL AND METHODS

Forty extracted human teeth were treated in vitro: Vector -system with polishing (VP) and abrasive fluid (VA), conventional ultrasonic system (U) and hand instrument (H). At intervals of 40 s, calculus removal was assessed using a 3D laser scanning device. Eight single-rooted teeth were treated in vivo with the Vector -system or hand instruments. Subgingival plaque samples were obtained for microbiological evaluation. After extraction, residual calculus was assessed by means of digitized planimetry.

RESULTS

In vitro efficiency of hand instruments was statistically higher compared with the conventional ultrasonic system (p < 0.05) and the Vector -system with no difference between U and VA (p > 0.05) and VA and VP (p > 0.05). Residual calculus following in vivo instrumentation was not different in the Vector and the hand instrument group (p > 0.05) but treatment time with the Vector -system was statistically higher (p < 0.05). A similar reduction of periopathogenic bacteria could be observed in both groups.

CONCLUSION

Using the Vector -system, root surfaces can be debrided as thoroughly as with conventional instruments. However, treatment is more time consuming than conventional debridement.

Removal of root substance with the Vectortm-system compared with conventional debridement in vitro

OBJECTIVE

The aim of the present study was to assess the removal of root substance with the Vector-system depending on different irrigation fluids and to compare the results with conventional methods for root debridement.

MATERIAL AND METHODS

Forty extracted human teeth were treated using four different methods: Vector-system with polishing fluid and metal curette (VP), Vector-system with abrasive fluid and metal curette (VA), conventional ultrasonic system (U) with insert tip "P" and hand instrument. Treatment of the calculus-free root surfaces was carried out for a total of 12 min. using an artificial periodontal pocket. At intervals of 120 s, the removal of dental hard tissues was assessed using a three-dimensional (3D) laser scanning device and the Match 3D software with an accuracy of 0.00001 mm(3).

RESULTS

No difference in the removal of root substance with the hand instrument (0.0055 mm(3)/s) and the Vector-system using the abrasive fluid (0.0044 mm(3)/s) could be observed (p=0.51). Using these two systems, a larger amount of root substance (p<0.05) was removed compared with the other methods (U: 0.0023 mm(3)/s, VP: 0.0022 mm(3)/s), which did not differ from each other (p=0.76).

CONCLUSIONS

The present study indicates that the Vector-system in combination with polishing fluid or conventional ultrasonics might be used for root debridement without extensive root substance removal.

Efficiency of subgingival calculus removal with the Vectortm-system compared to ultrasonic scaling and hand instrumentation in vitro

OBJECTIVE

The recently introduced Vector-system (Duerr Dental, Bietigheim-Bissingen, Germany) is recommended to be used in conjunction with different insert tips and irrigation fluids. The aim of the study was to assess subgingival calculus removal depending on the mode of operation and to compare the results to conventional methods for root debridement.

METHODS

Sixty extracted human teeth with calculus on the root surface were treated in an artificial periodontal pocket model using six methods: Vector-system with metal probe insert (VPP) or metal curette insert (VPC), both used with polishing fluid, Vector-system with metal probe insert (VAP) or metal curette insert (VAC), both used with abrasive fluid, EMS-ultrasonic system (U) and hand instrument (Gracey curette). Photographs of the root surface were taken at intervals of 10 s and calculus removal was assessed using a surface analysis software until the root surfaces were cleaned completely. Analysis of variances (ANOVA) of the ranks with subsequent comparison of mean ranks and calculation of homogeneous groups (Scheffe) were used for statistical analysis.

RESULTS

Employing the hand instrument, highest efficiency could be observed (0.340 mm2/s). Calculus removal with the Vector-system and metal probe insert (VPP: 0.036 mm2/s; VAP: 0.067 mm2/s) was less effective (p < 0.05) than using the system with metal curette inserts (VPC: 0.122 mm2/s; VAC: 0.209 mm2/s). Employing the abrasive fluid, removal of deposits with the metal curette insert was as efficient as with the conventional ultrasonic system (U: 0.199 mm2/s, p > 0.05).

CONCLUSION

The present in vitro study indicates that the efficiency of calculus removal with the Vector-system is significantly dependent on the selection of inserts and irrigation fluids.

Displacement amplitude of ultrasonic scaler inserts

OBJECTIVES

Scanning laser vibrometry is a noninvasive method of measuring the velocity, displacement amplitude and oscillation frequency of vibrating objects. The purpose of this study was to assess, using a scanning laser vibrometer (SLV), the performance of different designs of commercially available ultrasonic scaler generators by measuring the oscillatory characteristics of various scaler tips.

METHODS

Four ultrasonic generators were tested (Cavitron SPS and Cavitron Select (Dentsply, York, PA, USA) and Piezon Master 400 and Mini Piezon (Electro-Medical Systems, Switzerland)) with various designs of scaler tip. The tips were positioned with their anterior surface perpendicular to the direction of the laser. A graduated scale, placed over the manufacturer's power dial, enabled incremental power setting selection. For each power setting, the laser beam from the SLV was scanned over the surface of the oscillating tip.

RESULTS

The ranges of longitudinal displacement amplitudes (in micrometres) were as follows: Mini Piezon (P-tip): 12.90+/-1.44 to 44.03+/-7.80; Piezon Master 400 (P-tip): 16.02+/-2.66 to 35.85+/-5.29; Cavitron SPS (TFI-10 tip): 7.81+/-0.51 to 29.70+/-1.12; Cavitron Select (TFI-10 tip): 13.13+/-1.44 to 33.77+/-4.27; Cavitron SPS (TFI-3 tip): 5.50+/-0.46 to 31.35+/-3.62.

CONCLUSIONS

This study shows that there are differences between commercially available generators and that tip movement varies between tips of the same style as well as between the generator and tip design. Users of ultrasonic scalers should be made aware of this inherent variability that may influence clinical procedures.

Subjective intensity of pain during the treatment of periodontal lesions with the Vector-system

The aim of this study was to measure subjective intensities of pain during the treatment of periodontal lesions with the Vector-system when compared to pain occurring during the treatment with conventional methods. Twenty patients, each of whom had three teeth with comparable periodontal pocket depths, were treated using three different methods: (i) scaling and root planing with hand instruments, (ii) cleaning with a conventional ultrasonic instrument (Siroson S) and (iii) cleaning with the Vector-system. The subjective intensities of pain during the treatment were measured with an intermodal intensity comparison. A visual analog scale was used for the evaluation after the treatment. The results of the intermodal intensity comparison during treatment showed that the use of the Vector-system caused less pain than the cleaning with hand instruments or the conventional ultrasonic system (P < 0.05). The intermodal intensity comparisons of cleaning with hand instruments and cleaning with the conventional ultrasonic system were not significantly different (P > 0.05). These results could be confirmed by the visual analog scale. Using the Vector-system for cleaning periodontal lesions it is possible to reduce pain sensations compared to conventional methods. Using cleaning methods that cause less discomfort and pain, it might be possible to increase the patient's compliance during non-surgical periodontal therapy and recall.

Antimicrobial effects of mechanical debridement

Self-performed plaque removal using manual or powered toothbrushes and interdental cleaning devices is improved in subjects that have received oral hygiene instructions. Personal oral hygiene coupled with regular professional supragingival debridement may further improve the level of plaque control but still fails to achieve a completely plaque-free dentition. Both patient-performed and professional supragingival plaque removal has an effect on subgingival microbiota that is limited to the marginal 3 mm of the periodontal pocket. At sites with 4 mm or more of probing depth, only subgingival scaling leads to a significant reduction of the bacterial load. The subgingival microflora can be further reduced by pocket elimination surgery. Due to the sequence of bacterial recolonization that occurs following mechanical debridement, the level of periodontal pathogens such as B. forsythus, P. gingivalis and T. denticola may be reduced for several months. Mechanical debridement also influences the patient's immune system response, resulting in antibody titers and avidity against periodontal pathogens. As a basis for the restoration and maintenance of periodontal health, repeated subgingival debridement, as performed in supportive periodontal therapy, can reduce the number and proportions of periodontopathogenic bacteria in subgingival plaque. However, intensive subgingival scaling and root planing should be avoided in sites that probe less than 3 mm, as this is likely to traumatize the periodontium and cause attachment loss.