Introduction 1 2 16 3 21 25 28 6 9 23 14 15 3 21 25 28 14 7 The hypothesis behind this study is that different tooth-related factors (e.g., tooth type, site, plaque, residual inflammation, horizontal/vertical bone loss) and patient-related factors (e.g., age, sex, diagnosis, smoking) determine the initial outcome of nonsurgical and surgical periodontal therapy in single-rooted teeth. Thus, the aim of the present study was to identify patient and site factors that determine the initial outcome of nonsurgical and surgical periodontal therapy in single-rooted teeth using more recent statistical methods. Materials and methods Patients 8 24 Aggressive periodontitis: Patient is clinically healthy; that is, systemic diseases predisposing for periodontitis are not known; radiographic bone loss greater than or equal to 50% in at least two different teeth and age less that or equal to 35 years at time of diagnosis. 19 The study was approved by the Institutional Review Boards for Human Studies of the University of Heidelberg. Clinical examination 22 8 Radiographic examination and evaluation Before therapy, in 36 patients, full-mouth sets of periapical radiographs (Ektaspeed plus; Kodac, Rochester, NY) were obtained in XCP technique (XCP, Kentzler & Kaschner Dental, Ellwangen/Jagst, Germany). Intraoral size 0 (maxillary second incisors and mandibular anteriors) and 2 (all other regions) dental films were exposed to an X-ray source (Heliodent DS®, 60 kV, 7 mA, Sirona, Bensheim, Germany) and developed under standardized conditions (XR 24 Nova®, Dürr Dental, Bietigheim–Bissingen, Germany). 27 Therapy 26 4 Statistical analysis Data handling All data were entered into a personal computer program (Systat™ for Windows version 10, Systat, Evanston, IL; Schenk). Descriptive statistics were then calculated using another program (SPSS™, version 10.0.1, SPSS, Chicago IL) by an independent statistician (Lungeanu). Multilevel analyses were modeled by another independent statistician (Reitmeir) using a third program (SAS® version 6.12, SAS Institute, Cary, NC). Reproducibility 4 Treatment comparison The individual patient was considered as a statistical unit in this analysis. The main outcome variable for the comparison of the therapeutic effects of no further therapy, SRP, or AF was chosen to be the change of PPD. RAL-V was considered as a secondary endpoint. All other clinical parameters (GI, PlI) were control variables. 10 11 p p 10 11 n n n n p Results 1 n Table 1 Study population as related to age, sex, smoking habit, and diagnosis Variable n Percent Age 45.9 ± 10.9   Sex Female 22 53.7 Smoking Active 19 46.3 Former 12 29.3 Never 10 24.4 Diagnosis Aggressive 8 19.5 Reproducibility 2 Table 2 Intraexaminer reproducibility at baseline, 3, and 6 months examination Examination n s s Baseline 8,400 0.49 0.49 3 months 8,376 0.44 0.39 6 months 8,292 0.53 0.39 s Baseline data 3 4 p 4 5 p 5 p 5 p 5 Table 3 Clinical parameters at baseline, 3 and 6 months after therapy (mean ± standard deviation)   Baseline 3 months 6 months Sites 4,146 4,146 4,146 RAL-V (mm) 5.12 ± 2.20 4.87 ± 1.87 4.92 ± 1.84 PPD (mm) 3.25 ± 1.83 2.67 ± 1.19 2.67 ± 1.20 GI 0.78 ± 0.97 0.51 ± 0.86 0.51 ± 0.86 PlI 0.16 ± 0.51 0.32 ± 0.70 0.37 ± 0.74 Table 4 Clinical parameters at baseline as related to therapy (mean ± standard deviation) Sites No therapy SRP AF 1,440 Range 2,478 Range 198 Range RAL-V/mm 4.35 ± 1.82* 1.25–19.00 5.55 ± 2.30 1.75–18.00 5.39 ± 2.02 2.25–12.00 PPD/mm 2.45 ± 1.13* 0.25–2.75 3.66 ± 1.98 0.50–12.25 3.98 ± 2.02 1.00–10.50 GI 0.48 ± 0.84*  0.94 ± 1.00  1.02 ± 0.98  PlI 0.15 ± 0.49  0.16 ± 0.53  0.14 ± 0.49  SRP AF p Table 5 Clinical parameters at baseline as related to jaw (maxilla/mandible), tooth type (anterior/premolar), and site (interproximal/buccal and oral) (mean ± standard deviation)   Maxilla mandible premolar anterior interproximal buccal/oral Sites 1,926 2,220 1,590 2,566 2,764 1,382 RAL-V/mm 5.24 ± 2.14* 5.00 ± 2.26 5.19 ± 2.20* 5.07 ± 2.22 5.37 ± 2.26* 4.60 ± 2.01 PPD/mm 3.55 ± 1.88* 3.00 ± 1.78 3.47 ± 1.88* 3.12 ± 1.81 3.67 ± 1.82* 2.43 ± 1.59 GI 0.80 ± 0.98* 0.76 ± 0.96 0.83 ± 0.97* 0.75 ± 0.96 0.89 ± 0.98* 0.56 ± 0.89 PlI 0.11 ± 0.43* 0.19 ± 0.57 0.14 ± 0.48* 0.17 ± 0.53 0.18 ± 0.54* 0.11 ± 0.44 p Treatment effect 6 7 p 7 Table 6 Clinical parameters at 3 and 6 months after therapy as related to therapy (mean ± standard deviation)   3 months after therapy 6 months after therapy No therapy SRP AF No therapy SRP AF Sites 1,440 2,478 198 1,440 2,478 198 RAL-V (mm) 4.37 ± 1.76 5.13 ± 1.90 5.14 ± 1.64 4.47 ± 1.76 5.17 ± 1.85 5.11 ± 1.61 PPD (mm) 2.33 ± 0.96 2.84 ± 1.25 3.09 ± 1.34 2.35 ± 1.05 2.83 ± 1.24 2.99 ± 1.27 GI 0.36 ± 0.76 0.58 ± 0.90 0.69 ± 0.94 0.36 ± 0.76 0.58 ± 0.90 0.65 ± 0.93 PlI 0.22 ± 0.56 0.36 ± 0.74 0.52 ± 0.89 0.31 ± 0.68 0.41 ± 0.78 0.27 ± 0.65 SRP AF Table 7 Change of clinical parameters at 3 and 6 months after therapy as related to therapy (mean ± standard deviation)   3 months after therapy 6 months after therapy No therapy SRP AF No therapy SRP AF Sites 1,440 2,478 198 1,440 2,478 198 RAL-V (mm) 0.03 ± 0.74 0.41 ± 1.11* 0.26 ± 1.06* 0.12 ± 0.94 0.38 ± 1.20* 0.28 ± 1.18* PPD (mm) −0.11 ± 0.72 −0.82 ± 1.33* −0.89 ± 1.25* 0.09 ± 0.87 −0.82 ± 1.40* −0.99 ± 1.41* GI −0.13 ± 0.97 −0.36 ± 1.14* −0.33 ± 1.14* −0.13 ± 1.03 −0.36 ± 1.18* −0.36 ± 1.44* PlI 0.08 ± 0.69 0.20 ± 0.82* 0.37 ± 0.97* 0.16 ± 0.75 0.25 ± 0.87* 0.13 ± 0.68* SRP AF p Prognostic factors 8 9 p 8 9 p 9 p 9 Table 8 n   Estimate SE df F p Intercept −1.8776 0.1068 37   Current smoking −0.2875 0.1106 3,427 6.76 0.0094 Site (interproximal) −0.2341 0.0277 3,427 71.28 <0.0001 Aggressive periodontitis −0.2903 0.1308 3,427 4.93 0.0265 Baseline PPD 0.2746 0.0158 3,427 303.72 <0.0001 Baseline RAL-V 0.1832 0.0141 3,427 169.61 <0.0001 Table 9 n   Estimate SE df F p Intercept −1.6487 0.1037 38   Current smoking −0.3312 0.1055 3,451 9.86 0.0017 Jaw (maxilla) −0.1299 0.0324 3,451 16.05 <0.0001 Site (interproximal) −0.3664 0.0262 3,451 195.10 <0.0001 Tooth type (premolar) −0.0501 0.0338 3,451 2.20 0.1381 Baseline PPD 0.6162 0.0146 3,451 1774.31 <0.0001 Baseline RAL-V −0.0354 0.0128 3,451 7.63 0.0058 Baseline Plaque Index −0.0368 0.0244 3,451 2.27 0.1318 Scaling and root planing 0.1171 0.0392 3,451 4.48 0.0114 Access flap 0.0997 0.0861 3,451 4.48 0.0114 10 11 10 11 p p 10 11 Table 10 n   Estimate SE df F p Intercept −1.8290 0.1385 33   Current smoking −0.3758 0.1334 1,313 7.94 0.0049 Tooth type (premolar) −0.0763 0.0502 1,313 2.31 0.1292 Aggressive periodontitis −0.3311 0.1635 1,313 4.10 0.0431 Baseline PPD 0.2371 0.0256 1,313 85.86 <0.0001 Baseline RAL-V 0.2637 0.0242 1,313 118.36 <0.0001 Bone loss in % −0.0115 0.0016 1,313 50.58 <0.0001 Table 11 n   Estimate SE df F p Intercept −2.0771 0.1364 34   Current smoking −0.4646 0.1197 1,313 15.08 0.0001 Jaw (maxilla) −0.1469 0.0433 1,313 11.51 0.0007 Baseline PPD 0.6286 0.0119 1,313 2791.95 <0.0001 Baseline Plaque Index −0.0550 0.0332 1,313 2.75 0.0097 Infrabony defect −0.2932 0.0671 1,313 19.10 <0.0001 Discussion Study population 8 21 4 18 8 8 12 20 Treatment effect 2 6 15 28 28 Prognostic factors 5 13 29 7 30 5 It is interesting to note that the diagnosis of aggressive periodontitis affected RAL-V gains but not PPD reduction. It seems that patients suffering from aggressive periodontitis have a higher risk for recessions than patients with chronic periodontitis. p p p 5 p p 17 5 Within the limitations of the present study the following conclusions may be drawn: (1) Nonsurgical and surgical periodontal therapies are effective in single-rooted teeth; (2) severe interproximal bone loss and infrabony defects deteriorate the clinical results, and (3) there seem to be more defect-associated (tooth, site) factors influencing treatment outcome than patient-associated factors.