Learning root debridement with curettes and power-driven instruments. Part I: a training program to increase effectivity

Training in the use of the water jet and cold atmospheric plasma jet for the decontamination of dental implants

OBJECTIVES

Clinical trials testing new devices require prior training on dummies to minimize the "learning curve" for patients. Dentists were trained using a novel water jet device for mechanical cleaning of dental implants and with a novel cold plasma device for surface functionalisation during a simulated open flap peri-implantitis therapy. The hypothesis was that there would be a learning curve for both devices.

MATERIALS AND METHODS

11 dentists instrumented 44 implants in a dummy-fixed jaw model. The effect of the water jet treatment was assessed as stain removal and the effect of cold plasma treatment as surface wettability. Both results were analysed using photographs. To improve treatment skills, each dentist treated four implants and checked the results immediately after the treatment as feedback.

RESULTS

Water jet treatment significantly improved from the first to the second implant from 62.7% to 75.3% stain removal, with no further improvement up to the fourth implant. The wettability with cold plasma application reached immediately a high level at the first implant and was unchanged to the 4th implant (mean scores 2.7 out of 3).

CONCLUSION

A moderate learning curve was found for handling of the water jet but none for handling of the cold plasma.

CLINICAL RELEVANCE

Scientific rational for study: Two new devices were developed for peri-implantitis treatment (Dental water jet, cold plasma). Dentists were trained in the use of these devices prior to the trial to minimize learning effects.

PRINCIPAL FINDINGS

Experienced dentists learn the handling of the water jet very rapidly and for cold plasma they do not need much training.

PRACTICAL IMPLICATIONS

A clinical study is in process. When the planned clinical study will be finished, we will find out, if this dummy head exercise really minimised the learning curve for these devices.

New design of interdental rubber picks - does the archimedean screw design bring an improvement for experimental cleaning efficacy and force?

BACKGROUND

Up to date, interdental brushes (IDB) are the first choice for interdental cleaning because of their cleaning efficacy. Cylindrical ones must be selected individually according to the size/morphology of the interdental area (IDR), whereas conical ones cover a larger variability of IDR. However, there is a trend on the part of patients towards interdental rubber picks (IRP) which are in general conically shaped, and which seem to be linked with lower cleaning efficacy. A new IRP with an Archimedes´ screw design was developed to overcome this limitation. Therefore, the in vitro study aimed to measure the experimental cleaning efficacy (ECE) and force (ECF) during interdental use of IDBs versus the new IRP type.

METHODS

Three IRPs with different tapers (PHB angled: 0.039, PHB straight S: 0.027, Vitis straight M: 0.045; all Flexipicks, Dentaid, Cerdanyola del Vallès, Spain) were compared to one IDB (Interprox micro PHD 0.9, Dentaid, Cerdanyola del Vallès, Spain). IDR were reproduced by a 3D-printer (Form2, Formlabs Sommerville, MA, USA) according to human teeth and matched to equivalent pairs (isosceles triangle, concave, convex) in three different diameters (1.0 mm,1.1 mm,1.3 mm). Covered with simulated biofilm, pre-/ post-brushing situations of IDR (standardized, computer-aided ten cycles) were photographed and quantified by digital image subtraction to calculate ECE [%]. ECF were registered with a load cell [N]. Statistically significant differences were detected using the Mann-Whitney-U-test and the Kruskal-Wallis-test with Bonferroni correction for multiple testing.

RESULTS

Overall, the ECE (mean ± SD) was higher for IDB micro 0.9 (45.95 ± 11.34%, p < 0.001) compared to all IRPs (PHB angled: 25.37 ± 15.29%; PHB straight: 22.28 ± 16.75%; Vitis straight: 25.24 ± 12.21%; p ≤ 0.001), whereat best ECE was achieved in isosceles triangle IDR of 1.0-1.1 mm (IDB micro 0.9: 70.7 ± 7.7%; PHB angled S: 57.30 ± 4.43%; p < 0.001). The highest ECF occurred for Vitis straight M with 2.11 ± 0.46 N, while IDB micro 0.9 showed lowest ECF values (0.64 ± 0.14 N; p < 0.001).

CONCLUSIONS

IRP with an Archimedes´ screw design and a higher taper were associated with advanced ECE but also higher ECF, nevertheless, ECE didn't reach the cleaning efficacy of conventional IDBs.

Preclinical teaching of periodontal surgical concepts using common instructional models: A comparative assessment

OBJECTIVES

Some commonly used models utilized for teaching periodontal surgical techniques to dental students include pig mandible and periodontal typodonts. Currently, no study compares the learning and teaching outcomes following the use of one model to the other. This study is aimed at evaluating the effectiveness of the preclinical laboratory component on student understanding of concepts taught in the periodontal surgical course and assessing students' and faculty members' satisfaction with the instructional models.

METHODS

As part of the surgical periodontics course, 98 students took the final exam, with eighty students participating in only the pig mandible session and twenty-three students participating in both the pig jaw mandible and an additional session utilizing periodontal typodonts under the supervision of ten periodontal faculty members. Examination scores of students attending or not attending the laboratory session were analyzed by a two-sample t-test. A questionnaire evaluating the effectiveness of both models was given to faculty members and students who participated in both laboratory sessions. These results were analyzed by paired t-test.

RESULTS

Participation in the laboratory sessions did not significantly impact the final exam scores (p = 0.722). Students who had better didactic performance in the course performed better in the final exam, irrespective of laboratory participation. Both students and faculty members preferred typodont to the pig mandibles in learning or teaching periodontal surgical concepts, but both felt gaining flap management and flap refection experience to be better with the pig mandible model without statistical significance (p = 0.119 and p = 0.070, respectively).

CONCLUSION

Within the limitations of this study, we can conclude that laboratory sessions did not significantly improve student performance on the exam. Students and faculty members generally gave positive feedback on both instructional models. Periodontal typodont could be an alternative model for teaching dental students, periodontal surgical concepts.

A Sex-Specific Evaluation of Dental Students' Ability to Perform Subgingival Debridement: Randomized Trial

BACKGROUND

A successful periodontitis treatment demands good manual skills. A correlation between biological sex and dental students' manual dexterity is currently unknown.

OBJECTIVE

This study examines performance differences between male and female students within subgingival debridement.

METHODS

A total of 75 third-year dental students were divided by biological sex (male/female) and randomly assigned to one of two work methods (manual curettes n=38; power-driven instruments n=37). Students were trained on periodontitis models for 25 minutes daily over 10 days using the assigned manual or power-driven instrument. Practical training included subgingival debridement of all tooth types on phantom heads. Practical exams were performed after the training session (T1) and after 6 months (T2), and comprised subgingival debridement of four teeth within 20 minutes. The percentage of debrided root surface was assessed and statistically analyzed using a linear mixed-effects regression model (P<.05).

RESULTS

The analysis is based on 68 students (both groups n=34). The percentage of cleaned surfaces was not significantly different (P=.40) between male (mean 81.6%, SD 18.2%) and female (mean 76.3%, SD 21.1%) students, irrespective of the instrument used. The use of power-driven instruments (mean 81.3%, SD 20.5%) led to significantly better results than the use of manual curettes (mean 75.4%, SD 19.4%; P=.02), and the overall performance decreased over time (T1: mean 84.5%, SD 17.5%; T2: mean 72.3%, SD 20.8%; P<.001).

CONCLUSIONS

Female and male students performed equally well in subgingival debridement. Therefore, sex-differentiated teaching methods are not necessary.

Assessment of a developed pig cadaver model for teaching crown lengthening surgical procedures

Background

Information regarding using a pig cadaver model for teaching purposes in dentistry is limited, especially for periodontal surgery procedures. The aim of this study was to assess the feasibility and efficacy of teaching crown lengthening surgical procedures using a prepared pig cadaver model.

Methods

Mandibles of slaughtered pigs with subgingival crown fracture defects on two premolars and two molars on each side were prepared as periodontal surgery teaching cases. A resident group (n = 20) and an instructor group (n = 18) participated in assessing the efficacy of the model by completing questionnaires before and after training sessions. Data was either assessed descriptively or analyzed statistically with Wilcoxon signed-rank test with the significance level at α = 0.05.

Results

Results revealed that all the knowledge points showed statistically significant improvements (p < 0.05) except for the procedure to determine the quantity of bone removal during osteotomy procedures. Most residents rated the efficacy of the model obtained with 9.0 out of 10 scale. The data of effectiveness of the pig cadaver model from the instructor group ranged from 7.4 ± 1.4 to 9.0 ± 1.0.

Conclusion

Results of this study support feasibility in using prepared pig cadaver models to teach crown lengthening surgical procedures to postgraduates.

Results of an experimental study of subgingival cleaning effectiveness in the furcation area

BACKGROUND

Sufficient biofilm removal in the furcation area (FA) is a major challenge in the clinical practice of supportive periodontal therapy. The aim of the present experimental study was to simulate subgingival cleaning of the FA using a powered scaler (sonic scaler (AIR), ultrasonic scaler (US)) for conventional mechanical debridement versus two air polishing with nonabrasive powder (LAPA-1: glycine powder, LAPA-2: erythritol powder) and different nozzles for supra-/subgingival cleaning for each device.

METHODS

Seven trained and calibrated operators with ≥ 2 years each of professional experience in treating periodontitis used the instruments to clean 3D-printed replicas of six molars with through-and-through FA (four 3-rooted and two 2-rooted teeth) in a manikin head. AIR and US were used in the control group; air polishing instruments were used in the test group. For reproducible evaluation, the test teeth were separated vertically into two or three parts, illuminated with ultraviolet light, photographed and evaluated planimetrically. Treatment time (TrT, in s) and relative cleaning efficacy (RCE, in %) were measured.

RESULTS

Overall, 3-rooted molars (RCE in the entire FA, 23.19 ± 20.98%) could be cleaned significantly less effectively than 2-rooted molars (53.04 ± 28.45%, p < 0.001), regardless of the instrument used. In the cleaning of the entire FA, significantly higher RCE values were achieved with conventional mechanical debridement (AIR/US: 46.04 ± 25.96%/39.63 ± 22.02%; AIR vs. US: p > 0.05) than with air polishing (LAPA-1/LAPA-2: 34.06 ± 29.48%/17.09 ± 18.85%; LAPA-1 vs. LAPA-2: p < 0.001) regardless of whether a supra- or subgingival cleaning nozzle used (p < 0.001). Only LAPA-1 with a subgingival nozzle showed RCE values comparable to those of US (41.07 ± 28.95% vs. 39.63 ± 22.02%, p > 0.05). TrT was longest for US (299.40 ± 120.69 s) and shortest for LAPA-1 with a supragingival nozzle (129.67 ± 60.92 s, p < 0.001).

CONCLUSIONS

All of the examined instruments were effective to some degree in removing the simulated biofilm from the FA, but they differed substantially in cleaning efficacy. Only one air polishing device (LAPA-1) with a rigid subgingival nozzle was able to achieve RCE values similar to those of US. The current investigation confirmed that conventional mechanical debridement with powered scalers were most effective, but treatment took longer with these devices than air polishing.

Influence of motivation and a new digitized training program on undergraduate dental students during preclinical scaling training

BACKGROUND

The current study evaluated whether a new digitized scaling training program (DTP: n = 30; supervisor-student-ratio 1:10) improves the performance of undergraduate dental student during a preclinical course in regard to two different instruments [sonic scalers (AIR) and Gracey curettes (GRA)] compared to a conventional training program (CTP: n = 19; supervisor-student-ratio 1:4).

METHODS

All the participants received a two-hour lecture on both instruments, followed by a 12-week period with a weekly training program lasting 45 min (10 sessions); one group was supported by DTP. At the end of the training phase, all the participants performed the subgingival scaling of six equivalent test teeth using GRA and AIR. Treatment time, proportion of removed simulated biofilm (relative cleaning efficacy, RCE-b) and hard deposits (RCE-d) were recorded. By using a pseudonymized questionnaire with a 5-point Likert scale, self-assessment of scaling effort, handling, root surface roughness/destruction and effectiveness were evaluated. In addition, personal data such as age, gender, handedness, regularity of playing computer games/consoles and previous dental/technical or medical education were elevated and correlated with cleaning efficacy.

RESULTS

The DTP participants showed higher effectiveness in RCE-b compared to those who used the CTP with GRA (71.54% vs. 67.23%, p = 0.004) and AIR (71.75% vs. 62.63%, p ≤ 0.001), and the DTP students were faster with both instruments (p ≤ 0.001). For RCE-d, there was no significant difference between the DTP and CTP groups (GRA p = 0.471; AIR p = 0.158), whereas DTP showed better RCE-d results with GRA versus AIR (84.68% vs. 77.85%, p < 0.001). According to the questionnaire, no significant differences were detected between the training groups in terms of self-assessment, handling, treatment time, root surface roughness/destruction or effectiveness of the instruments. The CTP group favored AIR compared to GRA regarding the fatigue effect. The CTP and playing computer games/consoles regularly was correlated with lower RCE-b, whereas previous education in medicine/dentistry was correlated with higher RCE-b values.

CONCLUSIONS

Within the limitations of the study, the DTP with a reduced supervision effort compared to the CTP resulted in higher effectiveness and lower instrumentation time for removing simulated biofilms.

Evaluation of a systematic digitized training program on the effectivity of subgingival instrumentation with curettes and sonic scalers in vitro

Objectives

Whereas the key role of subgingival instrumentation in periodontal therapy is well known, the influence of operators’ experience/training with different devices on treatment results is yet uncertain. Therefore, we assessed untrained undergraduate students, working on manikins, as to how effectively they learn to use curettes (GRA) and sonic scalers (AIR); hypothesizing that AIR will result in higher relative cleaning efficacy (RCE) than GRA.

Material and methods

Before baseline evaluation (T0), 30 operators (9 males, 21 females) received a 2-h theoretical lesson for both instruments, followed by a 12-week period with a weekly digitized training program for 45 min. During three sessions (T1–T3), the operators had to instrument six equivalent test teeth with GRA and AIR. At T0–T3, treatment time, proportion of removed simulated biofilm (RCE-b), and hard deposits (RCE-d) were measured.

Results

At T0, RCE-b was in mean(SD) 64.18(25.74) % for GRA, 62.25(26.69) % for AIR; (p = 0.172) and RCE-d 85.48(12.32) %/ 65.71(15.27) % (p < 0.001). At T3, operators reached highest RCE-b in both groups (GRA/AIR 71.54(23.90) %/71.75(23.05)%; p = 0.864); RCE-d GRA/AIR: 84.68(16.84) %/77.85(13.98) %; p < 0.001). Both groups achieved shorter treatment times after training. At T3, using curettes was faster (GRA/AIR 16.67(3.31) min/19.80(4.52) min; p < 0.001).

Conclusions

After systematic digitized training, untrained operators were able to clean 70% of the root surfaces with curettes and sonic scalers.

Clinical relevance

It can be concluded that a systematic digitized and interactive training program in manikin heads is helpful in the training of root surface debridement.

How to train periodontal endoscopy? Results of a pilot study removing simulated hard deposits in vitro

OBJECTIVES

There is uncertainty regarding the benefits of periodontal endoscopy (PE) for subgingival instrumentation. Moreover, the influence of operators' experience and training with such a device on treatment results is unclear. Therefore, we compared in an in vitro study the use of PE for scaling and root planing (SRP) with the conventional non-surgical therapy, hypothesizing that using a PE allows to remove more simulated hard deposits than without (nPE), influenced by the operators' experience and training.

MATERIAL AND METHODS

A sonic device and Gracey curettes were utilized by 11 operators (six dentists, five dental hygienists) in periodontitis manikins heads. The time required for treatment and the proportion of removed simulated hard deposits by SRP were measured.

RESULTS

Using the PE led to a significant difference in removal of simulated hard deposits (%) (mean ± SD) irrespective of operators' experience (PE 90.78 ± 12.10% (range 58.80-100%); nPE 79.98 ± 22.15% (range 38.10-100%, p < 0.001)), sub-analyses for different tooth types demonstrated a significant difference in favor of PE for front teeth (p < 0.001) and in the upper jaw independent of the tooth type (p < 0.001). Comparison of treatment times for two quadrants with and without PE showed a significantly longer treatment time with PE (∆22.27 ± 17.98 mins, p <0.001).

CONCLUSIONS

Within the present pilot study, the use of PE led to more removal of simulated hard deposits but was concomitantly related to more time and financial effort. Using PE was most beneficial in the front area.

CLINICAL RELEVANCE

PE may provide additional benefits for the removal of hard deposits compared to traditional SRP. The beneficial effect of PE seems not to be influenced by operators experience nor by pocket probing depth.

Comparative effectiveness of hand scaling by undergraduate dental students following a two-week pre-clinical training course

BACKGROUND

The Bologna reform resulted in a drastic restructuring of pre-clinical training courses at the University of Zurich. The aim of this study was to assess student pre-clinical scaling/root planning skills after just 8.5 hours of manual training.

MATERIAL AND METHODS

Three consecutive classes of dental students (n = 41; n = 34; n = 48) were tasked with removing lacquer concrement from the maxillary left canine on a typodont using Gracey and universal (Deppeler M23A) curettes. At baseline (prior to instruction), a timed five-minute session of scaling/root planning was undertaken. The second scaling/root planning session was held immediately following training. Eight experienced dental hygienists and eight lay people served as positive and negative controls, using the same instruments and time limit, respectively. Instrumented teeth were collected, scanned and planimetrically analysed for the percentage of tooth surface cleaned. Statistical analyses were performed to assess the dental students' improvement after the training (Wilcoxon signed-rank test) and to compare it to that of laypeople and dental hygienists (Kruskal-Wallis rank sum test followed by Conover's post hoc test).

RESULTS

At baseline, the dental students' mean scaling scores of the cleaned surfaces were not significantly different than those of laypeople (29.8%, 31.0%, 42% vs 27.9%). However, after 8.5 hours of manual training, the students' ability to clean the maxillary tooth improved significantly and they achieved mean removal values of 61.7%, 79.5% and 76% compared to the 67.4% (P < .001) of the experienced dental hygienists (Tables Tables  and ). There were no statistically significant differences between the scores achieved by students after training and those achieved by experienced dental hygienists.

CONCLUSION

A shortened pre-clinical training time was sufficient for students to acquire the basic scaling/root planning skills needed in preparation for clinical training. Further research is needed to identify ways to help students consistently reach highest skill levels.

Removal of simulated biofilm: an evaluation of the effect on root surfaces roughness after scaling

BACKGROUND

Despite the development of less invasive devices, a debate exists about the benefits and risks of hand versus powered root surface instrumentation used in supportive periodontal therapy (SPT). The aim of the in vitro study was to differentially compare plaque removal efficacy and root surface roughening of newly developed sonic, ultrasonic scaler, and curettes in the hands of experienced versus less experienced operators.

MATERIALS AND METHODS

Sonic (AIR), ultrasonic devices (TIG), and double-gracey curettes (GRA) were utilized by seven experienced (EO) and four less experienced operators (LO) for root surface instrumentation of standardized plastic teeth on manikins' heads in a randomized sequence. The proportion of residual simulated plaque (RSP area in %) was planimetrically assessed, and the average root surface roughness produced (Ra and ∆Ra in μm) was measured by a precision profilometer.

RESULTS

The uninstrumented root surfaces showed a Ra of (median (Q25/Q75)) 1.00 μm (0.83/1.16). Following instrumentation, EO left significantly less RSP than LO regardless of the used instruments (20.00 % (10.00/34.00) vs. 26.00 % (12.00/44.00) p < 0.001), whereas the ∆Ra values (0.29 μm (-0.04/0.96) vs. 0.35 μm (-0.04/1.01), p = 0.237) failed to show significant differences. The surface roughness was higher with GRA followed by AIR then TIG regardless of operators' experience (p < 0.001).

CONCLUSION

Within the limits of the present study, the sonic device was most efficient in plaque removal, while the ultrasonic device produced the least surface roughness.

CLINICAL RELEVANCE

All three tested instruments seem effective in the mechanical root debridement during SPT, whereat the ultrasonic device show the smoothest root surface of all.

Removal of simulated biofilm: a preclinical ergonomic comparison of instruments and operators

BACKGROUND

Periodontal scaling might cause musculoskeletal disorders, and scaling instruments might not only have different effectiveness and efficiency but also differ in their ergonomic properties. The present study assessed ergonomic working patterns of experienced (EO) and less experienced operators (LO) when using hand and powered devices for periodontal scaling and root planning.

METHODS

In an experimental study using periodontally affected manikins, sonic (AIR), ultrasonic (TIG) and hand instruments (GRA) were used by 11 operators (7 EO/4 LO) during simulated supportive periodontal therapy. Using an electronic motion monitoring system, we objectively assessed the working frequency and positioning of hand, neck and head. Operators' subjective evaluation of the instruments was recorded using a questionnaire.

RESULTS

Hand instruments were used with the lowest frequency (2.57 ± 1.08 s(-1)) but greatest wrist deviation (59.57 ± 53.94°). EO used instruments more specifically than LO, and generally worked more ergonomically, with less inclination of head and neck in both the frontal and sagittal planes, especially when using hand instruments. All groups found hand instruments more tiring and difficult to use than powered instruments.

CONCLUSION

Regardless of operators' experience, powered instruments were used more ergonomically and were subjectively preferred compared to hand instruments.

CLINICAL RELEVANCE

The use of hand instruments has potential ergonomic disadvantages. However, with increasing experience, operators are able to recognise and mitigate possible risks.

Efficacy versus health risks: An in vitro evaluation of power-driven scalers

Background:

Power-driven instrumentation of root surfaces during supportive periodontal therapy is an alternative to hand instrumentation. The purpose of this pilot in vitro study was to investigate the efficacy of sub- and supragingival plaque removal with a sonic (AIR: Synea, W and H, Bürmoos, Austria) and two ultrasonic devices (TIG: Tigon+, W and H, Bürmoos, Austria; VEC: Vector, Dürr, Bietigheim-Bissingen, Germany) as well as the health-risk for dental professionals during treatment.

Materials and Methods:

The power-driven devices were utilized to remove plaque from model teeth in dummy heads. The percentage of residual artificial plaque after 2 min of supra- or subgingival instrumentation was calculated by means of image-processing techniques at four sites (n = 576) of each tooth. The Health-Risk-Index (HRI: spatter/residual plaque quotient) with the different power-driven devices was assessed during treatment.

Results:

The smallest amounts of residual plaque were found for the sonic device AIR (8.89% ± 10.92%) and the ultrasonic scaler TIG (8.72% ± 12.02%) (P = 0.707). Significantly more plaque was remained after the use of the ultrasonic scaler VEC (18.76% ± 18.07%) (P < 0.001). Irrespectively of the scaler, efficacy was similar sub- (10.7% ± 11.6%) and supragingivally (13.5% ± 17.2%) (P = 0.901). AIR/TIG demonstrated equal residual amounts of plaque sub- (P = 0.831) as well as supragingivally (P = 0.510). However, AIR/VEC and TIG/VEC were significantly in favor of AIR and TIG (P < 0.001). In contrast, the lowest HRI was found after using VEC (0.0043) and differed considerably for AIR (0.2812) and TIG (0.0287).

Conclusion:

Sonic devices are as effective as ultrasonic devices in the removal of biofilm but bear a higher risk to the dental professional's health concerning the formation of spatter.

Subgingival instrumentation to remove simulated plaque in vitro: influence of operators' experience and type of instrument

BACKGROUND

There is uncertainty regarding the benefits and risks of hand versus powered root surface instrumentation. Moreover, the influence of operators' experience on treatment results is unclear. We compared newly developed sonic, ultrasonic and hand instruments, hypothesizing that powered devices allow to remove more simulated plaque in less time than hand instruments, with significant influence of operators' experience.

METHODS

Sonic scaler (AIR), ultrasonic scaler (TIG) device and double Gracey curettes (GRA) were utilized by seven experienced operators (EOs) and four less experienced operators (LOs) in periodontitis manikin heads. The time required for treatment, the proportion of residual-simulated plaque and the weight loss caused by scaling as a proxy for root surface destruction were measured.

RESULTS

Using different instruments led to significantly different proportions of removed simulated plaque regardless of operators' experience (AIR, 80.2 ± 21.3 %, TIG, 69.9 ± 22.5 %, GRA, 73.1 ± 20.0 %) (p < 0.001). Treatment times did not significantly differ between EO and LO (p > 0.05). Weight loss was increased when using hand instead of powered instruments (p < 0.001), with significantly higher weight loss induced by LO than EO (p = 0.004).

CONCLUSION

Within the present study, EO did not remove more simulated plaque in less time but induced less root surface destruction. Using a sonic device was most beneficial for plaque removal.

CLINICAL RELEVANCE

Successful root surface debridement requires both time and training regardless of the used instrument. Hand instruments might cause more damage to root surfaces, especially in the hands of less experienced operators.

Retention of questionable and hopeless teeth in compliant patients treated for aggressive periodontitis

AIM

The aim of this study was to determine the survival rates of questionable and hopeless teeth in patients with aggressive periodontitis (AgP) and chronic periodontitis (CP) during 15 years of supportive periodontal therapy (SPT).

MATERIALS AND METHODS

Thirty-four AgP and 34 CP patients (SPT≥10 years) with bone loss of ≥50% at ≥2 teeth were consecutively recruited. Bone loss was measured on digitized radiographs and teeth were categorized as "questionable" (≥50 to <70% bone loss) or as "hopeless" (≥70%). Progression in pocket probing depths (PPD) during SPT, tooth loss and reasons for extraction were analysed.

RESULTS

In AgP patients, 262 teeth were considered as questionable and 63 as hopeless (CP: 149/51). During active periodontal therapy, 25 questionable and 26 hopeless teeth were extracted (CP: 12/16). During 15.3 ± 4.1 years of SPT of AgP 28 questionable and 15 hopeless teeth were removed (CP: 28/12). The mean tooth loss per patient during SPT in total was 0.14 (AgP) and 0.16 (CP) teeth/year. There were no significant differences in tooth loss or longitudinal progression of PPD between AgP and CP patients.

CONCLUSIONS

In patients with AgP, 88.2% (209 of 237) of questionable and 59.5% (22 of 37) of hopeless teeth survived 15 years during regular SPT in a dental school department.

Innovative educational methods and technologies applicable to continuing professional development in periodontology

Continuous professional development (CPD) in Periodontology refers to the overall framework of opportunities that facilitate a life-long learning practice, driven by the learner-practitioner and supported by a variety of institutions and individuals. CPD must address different needs for a great diversity of practitioners. It is clear that no particular methodology or technology is able to successfully accommodate the entire spectrum of CPD in Periodontology. Course designers must choose from and combine a wide array of methodologies and technologies, depending upon the needs of the learners and the objectives of the intended education. Research suggests that 'interactivity', 'flexibility', 'continuity' and 'relevance to learners' practice' are major characteristics of successful CPD. Various methods of mentoring, peer-learning environments and work-based learning have been combined with reflective practice and self-study to form the methodological backbone of CPD courses. Blended learning encompasses a wide array of technologies and methodologies and has been successfully used in CPD courses. Internet-based content learning management systems, portable Internet devices, powerful databases and search engines, together with initiatives such as 'open access' and 'open courseware' provide an array of effective instructional and communication tools. Assessment remains a key issue in CPD, providing learners with valuable feedback and it ensures the credibility and effectiveness of the learning process. Assessment is a multi-level process using different methods for different learning outcomes, as directed by current evidence and best practices. Finally, quality assurance of the education provided must follow CPD courses at all times through a structured and credible process.

Clinical effects after subgingival polishing with a non-aggressive ultrasonic device in initial therapy

OBJECTIVES

The Vector ultrasonic system provides root debridement supported by different abrasive irrigation fluids. The aim of this study was to investigate the clinical outcome of initial therapy with subgingival low-abrasive debridement.

MATERIAL AND METHODS

Twenty patients, who had at least two teeth with pocket depths >5 mm in each quadrant, took part in this prospective randomized clinical study. Patients were treated in a split-mouth design as one test quadrant (1) subgingivally with Vector fluid polish (VU-H) and as three control quadrants, (2) with only supragingival polishing (PO-H), (3) with hand instruments (HI-H) performed by a hygienist and (4) with hand instruments (HI-D) performed by a dentist. At baseline, 3 and 6 months after treatment, pocket depths and attachment levels (ALs) were measured and bleeding on probing (BOP) was recorded.

RESULTS

At 6-month evaluation, all groups showed an improvement in clinical parameters. No statistically significant differences in any of the investigated parameters could be observed between the Vector group and the hand scaling groups, or when comparing the results of the two different operators.

CONCLUSION

This study demonstrates that Vector treatment with polishing fluid was able to reduce pocket depths and the prevalence of BOP and improve clinical AL in a similar way as scaling with curettes.

Influence of handling-relevant factors on the behaviour of a novel calculus-detection device

OBJECTIVES

The aim of periodontal therapy is always the complete debridement of root surfaces with the removal of calculus and without damaging cementum. We have recently demonstrated the feasibility of a surface recognition device that discriminates dental surfaces by mathematical analysis of reflected ultrasound waves. This principle should enable the construction of calculus detecting ultrasonic device. Pre-clinical test results are presented here.

MATERIAL AND METHODS

An impulse generator, coupled to a conventional piezo-driven ultrasonic scaler, sends signals to the cementum via the tip of an ultrasound device. The oscillation signal reflected from the surface contains the information necessary to analyse its characteristics. In order to discriminate different surfaces, learning sets were generated from 70 extracted teeth using standardized tip angle/lateral force combinations. The complete device was then used to classify root surfaces unknown to the system.

RESULTS

About 80% of enamel and cementum was correctly identified in vivo (sensitivity: 75%, specificity: 82%). The surface discrimination method was not influenced by the application conditions examined. A new set of 200 tests on 10 teeth was correctly recognized in 82% of the cases (sensitivity: 87%, specificity: 76%).

CONCLUSIONS

It was shown in vitro that the tooth surface recognition system is able to function correctly, independent of the lateral forces and the tip angle of the instrument.

A sheep cadaver model for demonstration and training periodontal surgical methods

There is lack of data on the suitability of animal cadaver models for teaching purposes in dentistry. Here, we describe a model suitable for training for several periodontal surgical methods. Mandibles of freshly slaughtered Australian adult sheep and lambs were examined. Periodontal probing depths (PPDs) were measured at six sites of every tooth present. The following surgical techniques were critically analyzed: access flap with interrupted, continuous sutures; apically repositioned flap with periosteal sutures; coronally advanced flap with sling suture; gingivectomy; and distal wedge procedure. Probing depths were highest in the buccal furcation area of 1st and 2nd molars, where deep intrabony lesions were present in certain samples from adult sheep. Another area of increased probing depth was lingual to canines and incisors. Here, a pronounced lower dental pad of fibrous tissue was present. In this area, gingivectomy could always be accomplished. Fibrous tissue was also found distal to the most posterior molar, where the distal wedge procedure could be exercised. Access flaps and apically repositioned flaps could be performed particularly at premolars. Here, interrupted or continuous sutures were possible. Because of tight interdental contact areas, needle insertion was difficult at molars. After periosteal dissection, labial flaps at anterior teeth could easily be advanced coronally and sutured with sling sutures. Because of the teeth's dimensions and tight contact areas, simulation of more advanced techniques such as papilla preservation flaps was not possible. The sheep mandible seems to be a feasible training model for the demonstration and exercise of various periodontal surgical techniques for the treatment of periodontitis.

Learning root debridement with curettes and power-driven instruments. Part II: Clinical results following mechanical, nonsurgical therapy

BACKGROUND, AIMS

In a manikin study we recently assessed how effectively student operators were able to learn scaling with curettes (GRA) and power-driven instruments (PP). Calculating the debrided root area effectiveness was low in both groups without systematic training or without a motivational program. After 10 weeks (20 h) of training, operators reached a high effectiveness of 84.7% (GRA) and 81.6% (PP). The purpose of the present study was to evaluate the clinical outcome of nonsurgical treatment as performed by these student operators.

METHODS

In a clinical trial, 19 students trained in the use of Gracey curettes for 10 weeks (=20 h) (GRA10) and Periopolisher system for 1 week (=2 h) (PP1), and 20 students trained in the use of Gracey curettes for 1 week (GRA1) and the Periopolisher for 10 weeks (PP10) treated one patient each in a split-mouth design. At baseline and 6 months, we recorded probing depth (PD), probing attachment level (PAL) and bleeding on probing (BOP) by computer-assisted probing. Statistical analysis was carried out for moderate (category B) and deep sites (category C). Groups were compared using Student's t-tests (p<0.05).

RESULTS

Category B sites showed a PD reduction of 1.2/1.0 mm (GRA10/GRA1) and 1.1 mm (PP10/PP1). PAL gain was 0.5/0.3 mm (GRA10/GRA1) and 0.4/0.2 mm (PP10/PP1). In category C sites, PD reduction was 2.1/2.3 mm (GRA10/GRA1) and 2.0 mm (PP10/PP1) with a PAL gain of 0.6/0.9 mm (GRA10/GRA1) and 0.4 mm (PP10/PP1). BOP was significantly lower in all groups.

CONCLUSION

The results show that student operators who had received a systematical training on manikins and had attained different effectiveness results were able to treat periodontally diseased patients successfully using both Gracey and Periopolisher instruments.

Learning root debridement with curettes and power-driven instruments in vitro: the role of operator motivation and self-assessment

The influence of systematic dummy-head training with Periopolishe (PP, group A) and Gracey instruments (GRA, group B) on the effectiveness of root debridement was evaluated by Rühling et al., 2002 (9). Their results indicate that independent of the instrument used, untrained operators were only able to debride root surfaces at low levels of effectiveness. It was possible to increase effectiveness to a high level through systematic training in both groups. The aim of the present study was to assess the role of operator motivation and self-assessment on scaling effectiveness. Before baseline, operators were asked to answer a questionnaire rating the expectation of the instrument performance. Four groups of inexperienced operators (n = 11 each) received 10 weeks dummy-head training. In groups A (GRA) and B (PP), training was combined with a motivational programme. Groups C (GRA) and D (PP) received the same training, but no additional motivational programme. In a dummy-head, 10 test teeth were debrided and operators were asked to estimate their effectiveness of debridement at each test day. Effectiveness was calculated as percentage of debrided root area on 10 test teeth at different time points with an image analysis programme (NIH Image) and ANOVA. Two groups were compared using the Mann-Whitney U-test (unpaired) and the Wilcoxon signed ranks test (paired). Motivated groups (A and B) reached about 25% higher debridement results (p < 0.001) and were able to estimate their effectiveness more precisely compared to groups C and D. In the low motivation groups (C and D), overestimation of more than 20% was evident (p < 0.001). The questionnaires revealed underestimation of the GRA instruments and overestimation of PP instruments. Operator motivation and self-assessment greatly influence learning of effective root debridement.