Subgingival air polishing with trehalose powder during supportive periodontal therapy: use of a conical shaped tip during a randomized clinical trial.

BACKGROUND: This study investigated clinical parameters using a new air-polishing device compared to sonic scaling for subgingival biofilm removal during supportive periodontal therapy. The aim was to evaluate noninferiority of air-polishing compared to sonic scaling in deeper periodontal pockets with respect to pocket depth (PD). METHODS: In 44 participants, 2 single-rooted teeth [(PD) ≥ 5 mm] were treated using a split-mouth design. While a new air polishing device with a conical shaped tip was used for the experimental group, sonic scaling was performed in the control group. PD, clinical attachment level (CAL), and bleeding on probing (BOP) were recorded at baseline, (T0) after 3 months (T1) and 6 months (T2). Pain perception was rated using a visual analog scale (VAS; 0 = no pain, 100 = maximum pain). RESULTS: PD and CAL decreased significantly for both groups, while no intergroup differences were found (PD [mean, mm] control T0 5.96, T2 4.75; experimental T0 5.96, T2 4.8; intergroup p = 0.998; CAL [mean, mm] control T0 7.38, T2 5.84; experimental T0 7.28, T2 6.34; intergroup p = 0.368). For BOP, no intergroup differences were found from T0 to T2 (reduction control 42.5%; experimental 46.5% p = 0.398). Pain perception was significantly lower for air polishing (VAS [mean, mm] control 28.8, experimental 12.56; p = 0.006). CONCLUSION: None of the two treatment procedures showed inferior clinical effects with regard to PD, CAL and BOP with air polishing being more comfortable to patients. Trial registration The study was registered in an international trial register on August 14/08/2019, before the start of recruitment (German Clinical Trial Register number DRKS00017844).

Peri-implant bone-level changes in the second decade of loading with regard to the implant-abutment connection: a retrospective study on implants under systematic aftercare.

BACKGROUND: This retrospective study investigates the change in the peri-implant bone level (PBL) during the 2nd decade of intraoral function in patients complying with a 'supportive implant therapy' (SIT) program. The results were statistically analyzed with respect to the implant abutment connection used. METHODS: In a private practice, only patients with 20-year SIT compliance were identified. Of these, all patients with 10- and 20-year radiographs available were selected. Therefore, no control group was possible and implant losses had to be excluded. Two experienced researchers assessed the peri-implant bone levels. As three different abutment connection concepts (bone-level butt-joint, bone-level conical and tissue-level conical) and two different implant surfaces (machined vs. roughened) were involved, statistical analyses were performed to detect potential differences. RESULTS: Ninety-three implants from 36 patients with 20-year SIT compliance and available radiographs were included in the study. At study baseline (10 years intraoral), a mean bone loss of - 1.7 mm (median - 1.2; standard deviation [sd] 1.4, range: 0 to - 7.2) was recorded. After 20 years, we found a mean bone loss of - 2.5 mm (median - 2.3, sd 1.79, range: - 0.5 to + 7.4). Furthermore, we found a mean bone loss of 0.8 mm in intraoral function from year 10 to year 20 (mean: 0.08 mm per year); this change was independent of the abutment connection type. CONCLUSIONS: During the 2nd decade of function, peri-implant bone loss in patients with SIT compliance might be small in value and should not be expected in all implants.

Use of digital periodontal data to compare periodontal treatment outcomes in a practice-based research network (PBRN): a proof of concept.

BACKGROUND: Scientific studies in dentistry are mainly conducted at universities. However, most patients are treated in dental practices, which differ in many ways from treatment at the university. Through the establishment of practice-based research networks, however, it is also possible to examine studies in a real-world setting in dental practices. For this reason the aim of this non-interventional, observational study was to develop and evaluate a digital procedure to access, extract and analyse recorded clinical data in practices to assess periodontal treatment outcomes. METHODS: Participating periodontists were former or active postgraduate students of a master's course in periodontics in Freiburg who routinely used a digital periodontal diagnostic program. All available stored periodontal patient charts were extracted, anonymized and digitally sent to the study centre. RESULTS: In this study, data were collected from 6301 patients from 9 different practices. Information such as probing depth (PD), bleeding on probing (BOP), mobility, furcation and gingival attachment for 153,163 teeth at first visit were successfully transferred to the study centre. During the average observational period of 9.77 years, only 2.8% of all teeth were lost. The number of visits was significantly negatively correlated with BOP (p < 0.0001), and the number of BOP-positive sites was significantly correlated with deeper PDs (p < 0.001). CONCLUSION: The presented procedure was able to gather a large amount of practice-based periodontal data, and thus this study may support practice-based research networks. The data indicate that systematic and supportive periodontal therapy is successful on a practice-based level. Trial registration The study was internationally registered on 4 January 2017 in the German Clinical Trials Register (DRKS 00011448). https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00011448.

Long-term results of implants and implant-supported prostheses under systematic supportive implant therapy: A retrospective 25-year study.

BACKGROUND: Long-term data (>10 years) concerning the survival and success rates of implants and implant-supported prostheses are scarce. PURPOSE: The present investigation represents one of the first studies on dental implants covering an observational period of 25 years. MATERIALS AND METHODS: This study presents the results obtained in 26 patients with 75 implants who participated over a 23- to 28-year period in a supportive implant therapy (SIT) program at a private dental practice. We extracted existing data from the patients' files (pocket depths [PDs], bleeding on probing [BoP], radiographic peri-implant bone loss, and survival rates of the implant-supported prostheses). RESULTS: After 25 years, the SIT-compliant patients' implants had a survival rate of 95% (prostheses: 88%). The mean peri-implant probing depth was 3.69 mm (median: 3.33; SD: 1.06; range: 2-8.33). The mean peri-implant bone level was 1.84 mm (median: 1.82; SD: 1.20; range: -0.97-5.2). Finally, the prevalence (moment of last consultation) and incidence (during the entire observational period) of peri-implantitis were 7% and 30%, respectively. CONCLUSIONS: Under SIT conditions, clinicians may expect survival rates for implant-supported prostheses of >80%. Most implants (60%) did not develop signs of peri-implantitis over a 25-year period.

Supportive Implant Therapy (SIT): A Prospective 10-Year Study of Patient Compliance Rates and Impacting Factors.

The main objective of this study is to present patient compliance rates and influential factors for regular attendance in a systematic implant aftercare program (Supportive Implant Therapy; SIT) within a 10-year observation period. From 2005 to 2008, we identified 233 patients with 524 implants and implant-supported restorations at the study center. They had been instructed to attend an SIT program with 3-month recall intervals. A 2019 clinical prospective cohort study on 10-year compliance rates was performed. Data were assessed yearly in regression analyses to identify influential factors. Noncompliance rates increased during the period (4.8%, year 1; 39.7%, year 10). Total noncompliance was observed in four patients (1.7%) with 10 implants. "Age," "Gender," "Diabetes", and "Surgical case complexity" showed no correlation with patient compliance. "Smoking" and "Cardiovascular diseases" significantly influenced patients in one of ten years, while "Number of implants per patient", "Type of implant-supported prostheses", and "Pre-existing experience in a prophylaxis program" reached significance after several years. When patients with implant-supported restorations are strongly recommended and frequently remotivated to comply with an SIT program with 3-month recall, an approximately 60% compliance rate after 10 years is achievable. Previous prophylaxis program experience, increased number of implants per patient, and removable implant-supported prostheses may be strong influential factors for increased patient compliance.

A new technique for peri-implant recession treatment: Partially epithelialized connective tissue grafts. Description of the technique and preliminary results of a case series.

BACKGROUND: Data on implant recession coverage (RC) are very scarce. PURPOSE: To present a new surgical approach and preliminary results for the treatment of peri-implant soft tissue recession via partially epithelialized connective tissue grafts (PECTGs). MATERIALS AND METHODS: We harvested PECTGs from the palate using a double-blade scalpel. All donor sites were sutured and covered with a stent. Dissection lines were placed minimally coronal to the mucogingival border. The recipient areas were prepared epiperiostally. All PECTGs were sutured with the keratinized mucosa (KM) portion toward the local KM tissue and were subsequently widely covered by the local mucosal tissue layer. RESULTS: Fifteen patients with 22 implants were available for follow-up. The recession depth at baseline was 2.4 ± 1.1 mm (median: 2.5). After a mean observational period of 5 years, we found a mean recession value of 0.4 ± 0.5 mm (median: 0). We found a mean increase in the peri-implant KM width of 2.2 ± 1.1 mm (median: 1.5). In all cases, progression of the recession had stopped. None of the grafts was lost. The mean RC was 2 ± 0.9 mm (median: 1.5 mm) [88 ± 20% (median: 100)]. Complete RC was found in 64% of the implants. The results have remained stable for up to 13 years. CONCLUSION: Soft tissue recession around dental implants may successfully be treated using the PECTG technique.

Impact of supportive implant therapy on peri-implant diseases: A retrospective 7-year study.

AIM: Few data are available regarding the long-term impact of supportive implant therapy (SIT) on peri-implant diseases. We present long-term results on the possible effects of SIT on the peri-implant tissues. MATERIAL AND METHODS: In a private practice, 50 consecutive patients with 101 implants had attended an SIT programme for >6 years (SIT group). A second consecutive group comprised patients without SIT compliance (C group). We assessed pocket probing depth (PPD), bleeding on probing (BOP), bone loss (BL) and implant hygiene (QHI). Correlations between SIT compliance and the prevalence of peri-implant diseases were evaluated statistically. RESULTS: The inclusion criteria were met by 48 patients with 98 implants (SIT group) and 43 patients with 121 implants (C group). SIT group: Mucositis rate 30%; mean PPD 3.76 ± 0.86 mm; bone loss 1.02 ± 0.85 mm, peri-implantitis rate 4%. C group: Mucositis rate 68%; mean PPD 4.07 ± 1.18 mm; bone loss 1.53 ± 1.46 mm; and peri-implantitis rate 17%. Significant associations were found between SIT compliance and reduced peri-implant mucositis (p = .019), reduced highest PPD (p = .038) and peri-implantitis rates (p = .027). CONCLUSIONS: Patients under SIT were associated with lower incidence of peri-implant diseases. Patients without regular maintenance might exhibit a 4.25-fold increased risk for peri-implantitis. Therefore, SIT programmes should be considered essential.

Association of non-surgical periodontal therapy on patients' oral health-related quality of life-A multi-centre cohort study.

AIM: The aim of this multi-centre cohort study was to investigate the association of non-surgical periodontal therapy (NST) on the oral health-related quality of life (OHRQoL) in general and related to severity of periodontal disease and treatment modalities. MATERIALS AND METHODS: One hundred and seventy-two patients with periodontal disease from 18 dental practices were measured before and 6-8 weeks after NST using a standardized and validated OHRQoL instrument (Oral Health Impact Profile-G14, OHIP-G14). Another questionnaire was filled out by the dentists to evaluate the influence of treatment modalities and disease severity. RESULTS: Overall, the mean value of the OHIP baseline improved significantly after NST (p < 0.0001). Furthermore, a significant negative association between the severity of periodontitis and OHRQoL could be detected, and only patients with moderate and severe periodontitis showed a significant improvement of OHIP mean values (p < 0.0001). The results also indicated a significant association of the practitioners (p = 0.0362) as well as treatment modalities (favouring systemic antibiotics, p = 0.0066) regarding the improvement of the patients' OHRQoL. CONCLUSION: This study showed that NST is positively associated with patients' oral health-related quality of life. This association seems to depend on the disease severity and caregiver and treatment modality.

Extraoral Cementation Technique to Minimize Cement-Associated Peri-implant Marginal Bone Loss: Can a Thin Layer of Zinc Oxide Cement Provide Sufficient Retention?

This report describes the use of laboratory-fabricated crown intaglio replicas for extraorally prepared cementation of fixed restorations to implants. This technique minimizes excess cement and may therefore reduce the risk of cement-related marginal peri-implant bone loss. It is unclear whether the remaining thin layer of luting agent provides sufficient retention if low-adhesive zinc oxide (ZnO) cement is used. In 85 consecutive patients, 113 single crowns were cemented to implants using extraoral cementation technique (ECT) and ZnO cement. All patients were followed for 6 months and investigated for decementation. Seven events of decementation (incidence: 6.19%) were found in 7 patients (8.24%). ECT may represent a viable cementation technique for implant-supported single crowns, even using low-adhesion cements.

Decementation Rates and the Peri-Implant Tissue Status of Implant-Supported Fixed Restorations Retained via Zinc Oxide Cement: A Retrospective 10-23-Year Study.

BACKGROUND: Long-term data on clinical outcomes of restorations attached to implants via zinc oxide (ZnO) cement have been sparse. PURPOSE: The purpose of this study was to retrospectively investigate decementation rates and peri-implant tissue status of implant-supported fixed restorations retained by ZnO cement. MATERIALS AND METHODS: Between 1989 and 2003, 63 partially edentulous patients received 93 implants. Of these, 27 patients received 36 screwed single crowns (SC) and served as a control (C group). The other 36 patients had their restorations cemented using ZnO cement. They were subdivided into a SC group and a fixed dental prosthesis (FDP) group. After between 10 and 23 years (mean: 13.22 ± 3.21), all decementation events and peri-implant soft tissue status were evaluated using patient records. RESULTS: Decementation was assessed in 57 implants supporting 30 SCs and 16 FDPs. Five cases of decementation (8.77%) were recorded after a mean of 9.27 ± 7.05 years (range: 4.81-21.79). In the control group of vertically screwed SCs, five events of screw loosening (13.89%) were recorded in five patients (18.52%) after a mean of 5.84 ± 5.96 years (range: 0.56-15.05) within a 14.30 year observation period. No cases of peri-implantitis were observed in any group. The mean values of periodontal probing depths and bleeding on probing (BOP+) were 3.74 mm and 31.58%, respectively, for ZnO-cemented restorations, versus 3.76 mm and 25%, respectively, for the C group. No significant correlations regarding technical/biologic complications between the groups were detected. CONCLUSIONS: Within the limitations of this study, we conclude that the use of ZnO cement provides sufficient retention of implant-supported fixed restorations over long periods without biologic complications in form of peri-implantitis.

Minimizing excess cement in implant-supported fixed restorations using an extraoral replica technique: a prospective 1-year study.

PURPOSE: Cementation of implant-supported restorations poses two major challenges: (1) minimizing excess cement (reducing the risk of peri-implantitis), and (2) establishing sufficient retention (reducing the risk of decementation). This study presents the first data on a clinical cementation technique that might address both problems. MATERIALS AND METHODS: Between 2011 and 2013, 39 patients were provided with 52 implants supporting 52 single crowns (SCs). All restorations were cemented extraorally using replicas made of pattern resin and zinc oxide cement. All decementation events and the peri-implant soft tissue status were assessed and compared with those from a group of 29 patients with 40 conventionally cemented SCs (control). RESULTS: In the experimental group, after 12 months, decementation was recorded in three individuals (7.69%) with 3 SCs (5.77%). In the control group, after 12 months, no case of decementation was recorded. No cases of peri-implantitis were detected in either group. CONCLUSION: Within the limitations of this study, the authors conclude that the use of zinc oxide cement initially establishes sufficient retention of implant-supported fixed restorations independent of conventional or replica cementation techniques.

Clinical Outcome of Double Crown-Retained Mandibular Removable Dentures Supported by a Combination of Residual Teeth and Strategic Implants.

PURPOSE: There is a lack of data regarding the clinical outcome of removable partial dentures (RPDs) supported by a combination of residual natural teeth and implants placed in strategic positions. The aim of the present case series was to conduct a retrospective investigation of the clinical outcome of mandibular tooth-implant-retained partial dentures (TIRPD) rigidly retained via telescopic double crowns. MATERIAL AND METHODS: Between 1999 and 2010, 18 patients with reduced residual dentition (1 to 3 natural abutment teeth) and in need of an RPD received 1 to 3 implants in strategic positions for support of the removable prostheses. All TIRPDs were rigidly retained by telescopic crowns according to the Marburg Double Crown (MDC) technique; all prostheses were placed in a private practice. Tooth/implant survival and success rates, prosthetic maintenance requirements, and peri-implant parameters were analyzed retrospectively using patient records and clinical examinations during the final recall appointments. Only patients attending at least annual supportive post-implant hygiene therapy visits (SIT) were included. RESULTS: After a mean functional period of 5.84 ± 3 years (range: 3.01-12.21), 14 patients with 14 dentures supported by 24 implants and 27 teeth (mean number of abutments: 3.6) were available for assessment. Four teeth (survival rate: 85.19%) and no implants (survival rate: 100%) were lost. Peri-implantitis was observed around one implant (4.17%). All 14 dentures were functional (survival rate: 100%) and required only limited maintenance (i.e., screw loosening, acrylic resin fracture repairs, relining) amounting to 0.086 treatments per patient per year (T/P/Y). CONCLUSIONS: Within the limitations of this case series, it can be concluded that TIRPDs retained via MDCs might represent a viable treatment option in mandibles with few remaining abutment teeth. Further long-term clinical evaluations with a greater sample size are needed for a more detailed evaluation of this treatment concept.

The effect of keratinized mucosa width on peri-implant outcome under supportive postimplant therapy.

BACKGROUND: Long-ranging data on the influence of keratinized mucosa (KM) on peri-implant tissue status have been scarce. PURPOSE: Retrospective evaluation of peri-implant diseases and KM width in patients with versus without mucogingival surgery. MATERIALS AND METHODS: Under supportive postimplant therapy (SIT) in a private practice, 68 patients with peri-implant KM widths <1 mm were identified between 1992 and 2011 (eight dropouts). Thirty patients rejected surgery (control [C] group), and 30 patients agreed (intervention [I] group). After at least 1 year, KM width, mucositis, and peri-implant conditions were assessed. RESULTS: Sixty nonsmoking patients (n = 105 implants) were available for assessment after 12.10 ± 4.93 years. No implants were lost (survival rate: 100%). An average of 10.69 years after surgery, the I group implants showed a mean KM gain of 3.10 ± 1.43 mm (C group: 0 mm). The mucositis rates were as follows: I group: 38.98%; C group: 31.91%. Peri-implantitis was detected in two implants (1.87%) and two individuals (6.67%) in the I group. No significant differences between groups were found, except that the KM width values were significantly greater in the I group (p < 0.001). CONCLUSIONS: Low incidences of peri-implant diseases over long periods can be expected in patients attending SIT programs, independent of the absence or presence of KM.

Double crown-retained maxillary overdentures: 5-year follow-up.

BACKGROUND: There is a lack of data concerning implant-supported overdentures (IODs) retained by double crowns in the edentulous maxilla. PURPOSE: To perform a retrospective evaluation of clinical outcomes (survival/success rates) of maxillary overdentures retained on four implants via double crowns. MATERIAL AND METHODS: Between 1993 and 2011, 28 patients with edentulous maxillae were restored with overdentures supported by four implants with a Morse taper connection (Ankylos, Dentsply Friadent, Mannheim, Germany) and double crowns according to the Marburg Double Crown (MDC) technique in a private practice. For retrospective evaluation of implant and prosthetic survival (in situ criterion) and success (event-free observational period), only patients attending a professional maintenance program were included (n = 20). RESULTS: Twenty patients (13 female/ seven male, mean age: 63.45 ± 7.18 years) with 80 implants met the inclusion criteria. The mean follow-up period was 5.64 ± 3.50 years. One implant was lost (cumulative survival rate: 98.75%). Eight implants (10.1%) in two patients (10%) showed peri-implantitis; both patients were active smokers (cumulative success rate: 88.75%). All dentures were still functional (prosthetic survival rate 100%) at the time of investigation. Technical maintenance procedures (e.g., abutment loosening, screw loosening, acrylic fracture or relining) were required at a rate of 0.222/patient-year. CONCLUSIONS: Within the limitations of this study, we conclude that MDC-IODs are a promising treatment alternative for edentulous maxillae offering high implant and prosthesis survival rates > 98% and a limited incidence of biological and technical complications after a mean observational period of >5 years.

Unsplinted implants and teeth supporting maxillary removable partial dentures retained by telescopic crowns: a retrospective study with >6 years of follow-up.

OBJECTIVES: Data regarding tooth- and implant-supported maxillary removable partial dentures (TIRPDs) are scarce. The objective of this research was to perform a retrospective evaluation of the clinical long-term outcome of maxillary TIRPDs rigidly retained via telescopic crowns in patients undergoing supportive post-implant therapy (SIT). MATERIAL AND METHODS: The inclusion criteria were met by 26 patients restored with maxillary TIRPDs between 1997 and 2011 in a private practice. Primary crowns (Marburg double crowns, MDCs) on teeth were cemented, whereas those on implants were screw-retained. Using patient records and data from a cross-sectional clinical examination in 2013, the survival rates of the teeth, implants and prostheses, together with the biological and technical complications, were analyzed. RESULTS: After 6.12 ± 3.80 (range: 2-16) years of loading, 23 non-smoking patients with 23 dentures supported by 60 implants and 66 teeth were available for assessment. Nine teeth (survival rate: 86.36%) were lost, whereas 1 implant (survival rate: 98.36%) failed because of peri-implantitis. Although 30 implants (50%) in 16 patients (69.57%) showed bleeding on probing (BOP+), no further peri-implantitis was observed. The mean peri-implant probing depth (PPD) was 3.68 ± 0.71 mm. All dentures were functional and required technical maintenance efforts amounting to 0.128 treatments per patient per year (T/P/Y). CONCLUSIONS: Within the limitations of this study, we conclude that TIRPDs retained via MDCs may represent a viable treatment option for patients with residual maxillary teeth.

Increasing the Width of Keratinized Mucosa in Maxillary Implant Areas Using a Split Palatal Bridge Flap: Surgical Technique and 1-Year Follow-Up.

Sufficient soft-tissue coverage of maxillary implant sites may be difficult to achieve, especially after bone augmentation. The use of vestibular flaps moves keratinized mucosa (KM) toward the palate and may be disadvantageous for future peri-implant tissue stability. This study describes a new split palatal bridge flap (SPBF) that achieves tension-free wound closure and increases the KM width in maxillary implant areas. We began SPBF surgery with a horizontal incision in the palatal soft tissue to create a split-thickness flap. The second incision was performed perpendicular to the first, using a bridge design, at a distance of 10 to 15 mm. The superior layer can be moved crestally and sutured to cover the soft-tissue defect. The defect width was measured using a periodontal probe. The inferior layer was left exposed, and secondary wound healing created new KM in this region. This SPBF technique was performed on 37 patients. Of these, 16 patients were included in the assessment of clinical peri-implant outcomes. All of the SPBF procedures successfully resulted in a palatal regeneration of KM through secondary wound healing (mean regeneration width, 4.51 ± 1.17 mm; range, 3-6 mm). The 1-year follow-up of 16 patients revealed a mean pocket probing depth of 3.22 ± 0.6 mm with zero cases of peri-implantitis. The vestibular KM width at the involved implants was 2.82 ± 1.07 mm (range, 1.5-6 mm). Surgery for SPBF may be a promising technique for covering soft-tissue defects and increasing KM width in maxillary implant surgery.

A new technique for retaining double crowns on implants via custom-positioned vertical screws.

This report describes the use of custom-positioned vertical screws (CVS) to attach primary telescopic crowns to implant abutments. In a private practice setting, 37 patients with 40 double crown-retained implant overdentures (IODs) with a clearance fit (Marburg double crowns) were followed. All primary crowns on the 120 implant abutments were retained using CVS. After a mean followup period of 3.55 ± 1.37 years (range: 1.5 to 6.3 years), one abutment screwloosening incident was reported (incidence: 0.08%). No loosening of any of the screw-retained primary crowns occurred. CVS may represent a viable fixation concept for IODs.

Supportive post-implant therapy: patient compliance rates and impacting factors: 3-year follow-up.

AIM: To evaluate patient compliance rates and influential factors regarding a systematic SIT program. MATERIALS AND METHODS: Between 2005 and 2008, we identified all patients who were provided with implant-supported restorations in the study centre. They had been recommended to attend a SIT program with a 3-month recall. In 2012, a clinical retrospective cohort study on compliance rates over the first 3 years was performed different data were assessed in a regression analysis to identify potential influential factors. RESULTS: The inclusion criteria were met by 236 patients with 540 implants. Non-compliance rates increased over the 3 years (5.37%/7.78%/13.33%). Total non-compliance was observed in four patients (1.69%). No correlation to patient compliance was detected for "Age," "Gender," "Cardiovascular disease," "Pus/suppuration," or "Surgical case complexity." No decreasing effect of higher compliance rates on the patients' bleeding on probing (BOP+) values was found, but a statistical significance between lower compliance rates and increased pocket probing depth (PPD) was detected. The correlation between the presence of plaque and compliance did not reach statistical significance. CONCLUSIONS: When patients with implant-supported restorations are strongly recommended to comply with a SIT program with a 3-month recall, considerably high rates of compliance can be achieved.