Ying-Xin Gu* Jun-Yu Shi* Long-Fei Zhuang Shu-Jiao Qian Jia-Ji Mo Hong-Chang Lai
Authors’ affiliations: Ying-Xin Gu, Jun-Yu Shi, Long-Fei Zhuang, Shu-Jiao Qian, Jia-Ji Mo, Hong-Chang Lai, Department of Oral and Maxillo-Facial Implantology, Shanghai Ninth People’s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
Transalveolar sinus floor elevation using osteotomes without grafting in severely atrophic maxilla: a 5-year prospective study
Key words: dental implants, survival rates, transalveolar sinus floor elevation Abstract Objective: The aim of this study was to assess the clinical success of dental implants placed in severely atrophic maxilla (residual bone height ≤4 mm) using transalveolar sinus floor elevation (TSFE) without grafting. Furthermore, the implant stability during the healing period was also
Corresponding author: Prof. Hong-Chang Lai Department of Oral and Maxillo-Facial Implantology Shanghai Ninth People’s Hospital, School of Medicine Shanghai Jiaotong University 639 Zhizaoju Road, Shanghai 200011 China Tel.: +86 21 23271699 (ext. 5298) Fax: +86 21 53073068 e-mail: [email protected]
evaluated. Materials and methods: Twenty five generally healthy patients with 37 Straumannâ Standard Plus SLA implants were included in the study. After a modified Summers TSFE without grafting was performed, the smooth collar was embedded 0.5–1 mm beneath the cortical bone level. Follow-ups were conducted at 12, 36, and 60 months after crown placement. Implant survival rate, resonance frequency analysis (RFA), and clinical and radiographic parameters were evaluated. Results: At 5-year follow-up, 35 implants fulfilled the survival criteria, representing a 5-year cumulative survival rate of 94.6% at implant level and 92% at subject level. The mean value of implant stability quotient (ISQ) ranged from 67.8 to 72.8, and the lowest values were reached at 4 weeks. No significant difference was found with the passage of time in modified plaque index (P = 0.92), pocket probing depth (P = 0.34), and modified bleeding index (P = 0.4). The average residual bone height was 2.81 mm (SD: 0.74 mm) in this study. The average crestal bone loss (CBL) significantly increased from 0.83 mm at 1-year examination to 1.47 mm at 3-year examination (P < 0.001). The average CBL remained stable at years 3 and 5 (1.47 vs. 1.54 mm, P = 0.083). Conclusion: According to the current evidence, it is feasible to place cylindrical implants in severely atrophic maxilla. High survival rate could be achieved following TSFE without grafting at least within 5-year follow-up.
*These authors contributed equally to this work. Date: Accepted 4 December 2014 To cite this article: Gu Y-X, Shi J-Y, Zhuang L-F, Qian S-J, Mo J-J, Lai H-C. Transalveolar sinus floor elevation using osteotomes without grafting in severely atrophic maxilla: a 5-year prospective study. Clin. Oral Impl. Res. 00, 2014, 1–6 doi: 10.1111/clr.12547
Implant treatment in posterior maxilla is commonly faced with great challenges due to the limited residual bone height and poor bone quality. Efforts have been made to allow successful implant treatment in atrophic posterior maxillae. Transalveolar sinus floor elevation (TSFE) described by Summers (1994) has been proven to be a predictable surgical procedure to vertically increase the bone volume in atrophic maxilla with osteotomes with increasing diameters (Emmerich et al. 2005; Tan et al. 2008; Chao et al. 2010). Moreover, the TSFE technique is considered as less invasive, less time-consuming and more cost-effective compared with lateral approaches (Listl & Faggion 2010). Many studies showed that grafting materials should be simultaneously used to maintain the space below the elevated sinus membrane and to provide scaffolds for endo-
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
sinus bone formation. These studies demonstrated that high survival rate can be achieved using TSFE with simultaneous grafting (Zitzmann & Scharer 1998; Rosen et al. 1999; Ferrigno et al. 2006; Pjetursson et al. 2009b; Crespi et al. 2010). Subsequently, some clinicians tried to apply the TSFE procedure without any grafting materials, and the reported survival rate was between 88.7% and 100% with a mean observation period ranging from 12 to 55 months (Cavicchia et al. 2001; Leblebicioglu et al. 2005; Ferrigno et al. 2006; Jurisic et al. 2008; Schmidlin et al. 2008; Gabbert et al. 2009; Nedir et al. 2009a; Fermergard & Astrand 2012). Recently, two randomized controlled clinical trials concluded that the application of grafting materials had no significant advantages in terms of short-term clinical success (Nedir et al. 2013; Si et al. 2013).
1
Gu et al Transalveolar sinus floor elevation
According to previous consensus, the TSFE technique is recommended to be performed when residual bone height (RBH) ≥6 mm (Tan et al. 2008; Tonetti & Hammerle 2008). On the other hand, several studies have reported favorable results following TSFE in severely atrophic maxilla. In a retrospective study, 58 tapered implants were placed in maxilla following TSFE without grafting. The average RBH was 2.87 mm. The survival rate after 22 months of loading was 91.4% (Winter et al. 2002). Nedir reported 100% survival rate at 1-year follow-up following TSFE without grafting. It was claimed that hydrophilic surface (SLActive) and tapered implants could help to achieve successful osseointegration when RBH was 10 cigarettes/day); subject to uncontrolled periodontal diseases; and unwilling to participate in this study or refused to give informed consent. Surgery and prosthetic procedures
The implant placement was planned based on pre-surgical assessment. Panoramic radiographs were taken for all patients. The residual bone height was measured on panoramic radiographs, and each height was assessed twice to obtain the average. For all the cases, local anesthesia was used. Following a midcrestal incision, a full-thickness mucoperiosteal flap was reflected. After implant site was prepared to the depth about 1–2 mm away from the sinus floor, a modification of Summers TSFE was performed to elevating the sinus membrane until the final depth. The Valsalva maneuver test was performed before implants placement. Any patient with membrane perforation was excluded from the study. All implants were seated in the osteotomy site until 0.5–1 mm of the smooth collar was embedded below the bone. The wound was closed with Ethilon 5-0 nylon sutures. After surgery, anti-inflammatory amoxicillin (Xinya Co., Shanghai, China, 500 mg, three times a day for 7 days) and metronidazole (Xinyiwanxiang, Shanghai, China, 400 mg, three times a day for 7 days) were used. In addition, chlorhexidine oral rinse (0.12%) was prescribed for 60 s five to six times a day for 14 days. After a healing time of 3–4 months, cement-retained single crowns and solely implant-supported fixed dental prostheses were fabricated and delivered to the patients. Outcome variables Survival criteria
The implant survival criteria were determined by the following: no clinical detectable implant mobility, no pain or any subjective sensation, no recurrent peri-implant infection,
At implant installation as well as after 1, 2, 4, 6, 8, and 12 weeks after surgery, resonance frequency analysis (RFA) measurements were taken by the OsstellTM mentor (Integration Diagnostics AB, Goteborg, Sweden). For each individual implant, a standardized abutment (SmartpegTM; Integration Diagnostics AB, Gamlestadvagen 3B, Goteborg, Sweden) was inserted and a transducer probe (OsstellTM mentor Probe II) was held to display the ISQ value. Three different directions (buccal, lingual, and occlusal) were detected at each observation time point, and a mean value of the three directions was applied for statistical analysis. Clinical assessment
The following clinical variables were recorded: modified plaque index (mPI), pocket probing depth (PPD), and modified bleeding index (mBI). All the measurements were taken by the same dentist using a periodontal probe (15 UNC/CP-11.5B Screening Color-Coded Probe, Hu-Friedy, Chicago, IL, USA). Radiographic assessment
Periapical radiographs were taken immediately after implant surgery, at 1-year, 3-year, and 5-year examination. For standardization, a paralleling technique with a Rinn film holder (XCP Instruments; Rinn Corporation Elgin, Elgin, IL, USA) was conducted. Radiographic analysis was conducted by a software program (SIDEXIS 1.12; Sirona Dental System GmbH, Bensheim, Germany). The following parameters were measured and averaged at the mesial and distal implants side: residual bone height (RBH), marginal bone level (MBL), and crestal bone loss (CBL) (Fig. 1). Radiographic assessments were conducted by two assistants who were not involved in this study. Follow-up assessment
The baseline assessment of radiographic parameters was performed immediately after implants placement. Patients were recalled at 12, 36, and 60 months after implant surgery. Implant complications, mPI, PPD, mBI, and radiographic analysis were performed during each visit (Mombelli et al. 1987; Muller et al. 2000). Radiographic analysis was conducted by two examiners (X.X.Z and X.Z) not involved in this study.
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Gu et al Transalveolar sinus floor elevation
measurements of two examiners showed high agreement. Implant survival
Twenty eight patients (13 women and 15 men) were enrolled in the study. Two patients were excluded because of membrane perforation according to the Valsalva maneuver test. Another patient was excluded because of refusal to attend the follow-up examination. Finally, 25 patients with 37 implants were included in the study. One implant lost 4 months after implant surgery and another lost 1 month after loading. 23 patients and 35 implants fulfilled the survival criteria, representing a 5-year cumulative survival rate of 94.6% at implant level and 92% at subject level. RFA measurements Fig. 1. Radiographic assessment. Reference lines were drawn as follows: (a) a line at most apical implant–bone contact at the mesial site or at the distal site; (b) a line at most coronal level of implant–bone contact at the mesial site or at the distal site; (c) a line at most coronal level of the implant shoulder. (a) Residual bone height (RBH): the distance between line (a) and line (b) at baseline; (b) marginal bone level (MBL): the distance between line (b) and line (c) at each visit; (c) crestal bone loss (CBL): an increase of MBL from each visit to baseline examination.
Statistical analysis
Data analysis was performed using a statistical software package STATA (version 11.0; StataCorp, College Station, TX, USA). The level of significance was set at a = 0.05. The interexaminer reliability was determined by intraclass correlation coefficient (ICC) for continuous variables (including RBH and CBL). The skewness and kurtosis test were used to test for normality of distribution of the data. Mean and standard deviation were calculated for quantitative variables to assess the clinical and radiographic parameters. The Friedman test was performed for the comparison of mBI, mPI, PPD, MBL, and CBL at different time point. Wilcoxon sign-rank test was performed for pairwise comparison of MBL and CBL at each time point. The Bonferroni correction was applied for correction of multiple testing, and the P-value was corrected by p/k (k, frequency of multiple testing).
Results Interexaminer agreement
Intraclass correlation coefficient (ICC) was 0.982 for RBH and 0.979 for MBL. The
One implant was lost 4 months after surgery. Thus, sequential RFA measurements were taken on 25 patients. The mean implant stability quotient (ISQ) values obtained at each time point are present in Table 1 and Fig. 2. At implant installation, the ISQ values ranged from 58.7 to 74, with a mean value of 70.1 (SD 5.15). The mean ISQ values decreased to 69.2 at 1 week and 68.3 at 2 weeks. The lowest mean ISQ value of 67.8 was reached at 4 weeks. Following this, the mean ISQ values increased to 70.1 at 6 weeks and 71.8 at 8 weeks. Between 8 and 12 weeks, the mean ISQ values increased to 72.8 finally. Clinical assessment
Table 2 shows the clinical parameters at each visit. All patients showed acceptable oral hygiene. The mBI was 0.63, 0.71, and 0.66 at 1-year, 3-year, and 5-year examination, respectively. The mPI was 0.34, 0.51, and 0.46 at 1-year, 3-year, and 5-year examination, respectively. The PPD was 3.03, 3.17, and 3.11 at 1-year, 3-year, and 5-year examination, respectively. No significant difference was found with the passage of time in all three parameters.
Table 1. Mean ISQ values at each time point N = 25
Mean
Median
SD
Baseline 1-week 2-week 4-week 6-week 8-week 12-week
70.1 69.2 68.3 67.8 70.1 71.8 72.8
71 70 69 69 71 72 73
5.15 4.01 4.84 4.42 2.93 2.59 2.54
ISQ, implant stability quotient.
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Fig. 2. Diagram visualizing the mean ISQ values at all observation periods.
Radiographic assessment
Table 3 shows the radiographic parameters at each visit. The RBH ranged from 1.7 to 3.8 mm, with a mean value of 2.81 mm (SD: 0.74 mm) in this study. The average MBL significantly increased from 1.56 mm at baseline to 2.39 mm (P < 0.001) at 1-year examination and 3.03 mm (P < 0.001) at 3year examination. The average MBL remained stable at years 3 and 5 (3.10 vs. 3.03 mm, P = 0.083). Thus, the average CBL significantly increased from 0.83 mm at 1year examination to 1.47 mm at 3-year examination (P < 0.001). The average CBL remained stable at years 3 and 5 (1.47 vs. 1.54 mm, P = 0.083). A visible radio-opaque structure could be detected in 47.2%, 42.9%, 37.1%, and 40% of the implants at baseline, 1-year, 3-year, and 5-year examination. At final examination, about 60% patients showed nearly 2-mm-high cloudy new bone formation. Slightly decreased bone height above the apex of the implants was found in about 15% patients. About 25% patients did not show obvious difference in endo-sinus bone height. Fig. 3 shows one typical example of all the subjects included in the study.
Discussion The aim of present study was to assess the clinical success of dental implants placed in severely atrophic maxilla (RBH ≤ 4 mm) using TSFE without grafting and evaluate the stability of cylindrical implants during the healing period. In this study, 25 patients with 37 implants were included. The average residual bone height was 2.81 mm. At 5-year follow-up, 23 patients and 35 implants fulfilled the survival criteria, representing a 5-year cumulative survival rate of 94.6% at implant level and 92% at subject level. This was in line with those reported by other studies (Winter et al. 2002; Nedir et al. 2009b, 2013). This indicated that
3 |
Clin. Oral Impl. Res. 0, 2014 / 1–6
Gu et al Transalveolar sinus floor elevation
Table 2. Summary of clinical parameters mean(median) ± SD 1-year (n = 23) 3-year (n = 23) 5-year (n = 23) Friedman test
mBI
mPI
PPD (mm)
0.63(1) 0.60 0.71(1) 0.71 0.66(1) 0.58 P = 0.40
0.34(0) 0.48 0.51(1) 0.51 0.46(0) 0.61 P = 0.25
3.03(3) 0.57 3.17(3) 0.75 3.11(3) 0.83 P = 0.40
mPI, modified plaque index; PPD, pocket probing depth; mBI, modified bleeding index.
Table 3. Summary of radiographic parameters mean(median) ± SD Baseline (n 1-year (n = 3-year (n = 5-year (n =
= 25) 23) 23) 23)
RBH (mm)
MBL (mm)
2.81(2.80) 0.74 – – –
1.56(1.49) 2.39(2.35) 3.03(2.52) 3.10(2.67)
CBL(mm)
0.27① 0.36② 0.96③ 0.94*④
– 0.83(0.82) 0.50⑴ 1.47(1.18) 1.02⑵ 1.54(1.26) 1.00*⑶
Friedman test: *significance P < 0.001. Wilcoxon sign-rank test: Significance (P < 0.008), ①
Authors’ affiliations: Ying-Xin Gu, Jun-Yu Shi, Long-Fei Zhuang, Shu-Jiao Qian, Jia-Ji Mo, Hong-Chang Lai, Department of Oral and Maxillo-Facial Implantology, Shanghai Ninth People’s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
Transalveolar sinus floor elevation using osteotomes without grafting in severely atrophic maxilla: a 5-year prospective study
Key words: dental implants, survival rates, transalveolar sinus floor elevation Abstract Objective: The aim of this study was to assess the clinical success of dental implants placed in severely atrophic maxilla (residual bone height ≤4 mm) using transalveolar sinus floor elevation (TSFE) without grafting. Furthermore, the implant stability during the healing period was also
Corresponding author: Prof. Hong-Chang Lai Department of Oral and Maxillo-Facial Implantology Shanghai Ninth People’s Hospital, School of Medicine Shanghai Jiaotong University 639 Zhizaoju Road, Shanghai 200011 China Tel.: +86 21 23271699 (ext. 5298) Fax: +86 21 53073068 e-mail: [email protected]
evaluated. Materials and methods: Twenty five generally healthy patients with 37 Straumannâ Standard Plus SLA implants were included in the study. After a modified Summers TSFE without grafting was performed, the smooth collar was embedded 0.5–1 mm beneath the cortical bone level. Follow-ups were conducted at 12, 36, and 60 months after crown placement. Implant survival rate, resonance frequency analysis (RFA), and clinical and radiographic parameters were evaluated. Results: At 5-year follow-up, 35 implants fulfilled the survival criteria, representing a 5-year cumulative survival rate of 94.6% at implant level and 92% at subject level. The mean value of implant stability quotient (ISQ) ranged from 67.8 to 72.8, and the lowest values were reached at 4 weeks. No significant difference was found with the passage of time in modified plaque index (P = 0.92), pocket probing depth (P = 0.34), and modified bleeding index (P = 0.4). The average residual bone height was 2.81 mm (SD: 0.74 mm) in this study. The average crestal bone loss (CBL) significantly increased from 0.83 mm at 1-year examination to 1.47 mm at 3-year examination (P < 0.001). The average CBL remained stable at years 3 and 5 (1.47 vs. 1.54 mm, P = 0.083). Conclusion: According to the current evidence, it is feasible to place cylindrical implants in severely atrophic maxilla. High survival rate could be achieved following TSFE without grafting at least within 5-year follow-up.
*These authors contributed equally to this work. Date: Accepted 4 December 2014 To cite this article: Gu Y-X, Shi J-Y, Zhuang L-F, Qian S-J, Mo J-J, Lai H-C. Transalveolar sinus floor elevation using osteotomes without grafting in severely atrophic maxilla: a 5-year prospective study. Clin. Oral Impl. Res. 00, 2014, 1–6 doi: 10.1111/clr.12547
Implant treatment in posterior maxilla is commonly faced with great challenges due to the limited residual bone height and poor bone quality. Efforts have been made to allow successful implant treatment in atrophic posterior maxillae. Transalveolar sinus floor elevation (TSFE) described by Summers (1994) has been proven to be a predictable surgical procedure to vertically increase the bone volume in atrophic maxilla with osteotomes with increasing diameters (Emmerich et al. 2005; Tan et al. 2008; Chao et al. 2010). Moreover, the TSFE technique is considered as less invasive, less time-consuming and more cost-effective compared with lateral approaches (Listl & Faggion 2010). Many studies showed that grafting materials should be simultaneously used to maintain the space below the elevated sinus membrane and to provide scaffolds for endo-
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
sinus bone formation. These studies demonstrated that high survival rate can be achieved using TSFE with simultaneous grafting (Zitzmann & Scharer 1998; Rosen et al. 1999; Ferrigno et al. 2006; Pjetursson et al. 2009b; Crespi et al. 2010). Subsequently, some clinicians tried to apply the TSFE procedure without any grafting materials, and the reported survival rate was between 88.7% and 100% with a mean observation period ranging from 12 to 55 months (Cavicchia et al. 2001; Leblebicioglu et al. 2005; Ferrigno et al. 2006; Jurisic et al. 2008; Schmidlin et al. 2008; Gabbert et al. 2009; Nedir et al. 2009a; Fermergard & Astrand 2012). Recently, two randomized controlled clinical trials concluded that the application of grafting materials had no significant advantages in terms of short-term clinical success (Nedir et al. 2013; Si et al. 2013).
1
Gu et al Transalveolar sinus floor elevation
According to previous consensus, the TSFE technique is recommended to be performed when residual bone height (RBH) ≥6 mm (Tan et al. 2008; Tonetti & Hammerle 2008). On the other hand, several studies have reported favorable results following TSFE in severely atrophic maxilla. In a retrospective study, 58 tapered implants were placed in maxilla following TSFE without grafting. The average RBH was 2.87 mm. The survival rate after 22 months of loading was 91.4% (Winter et al. 2002). Nedir reported 100% survival rate at 1-year follow-up following TSFE without grafting. It was claimed that hydrophilic surface (SLActive) and tapered implants could help to achieve successful osseointegration when RBH was 10 cigarettes/day); subject to uncontrolled periodontal diseases; and unwilling to participate in this study or refused to give informed consent. Surgery and prosthetic procedures
The implant placement was planned based on pre-surgical assessment. Panoramic radiographs were taken for all patients. The residual bone height was measured on panoramic radiographs, and each height was assessed twice to obtain the average. For all the cases, local anesthesia was used. Following a midcrestal incision, a full-thickness mucoperiosteal flap was reflected. After implant site was prepared to the depth about 1–2 mm away from the sinus floor, a modification of Summers TSFE was performed to elevating the sinus membrane until the final depth. The Valsalva maneuver test was performed before implants placement. Any patient with membrane perforation was excluded from the study. All implants were seated in the osteotomy site until 0.5–1 mm of the smooth collar was embedded below the bone. The wound was closed with Ethilon 5-0 nylon sutures. After surgery, anti-inflammatory amoxicillin (Xinya Co., Shanghai, China, 500 mg, three times a day for 7 days) and metronidazole (Xinyiwanxiang, Shanghai, China, 400 mg, three times a day for 7 days) were used. In addition, chlorhexidine oral rinse (0.12%) was prescribed for 60 s five to six times a day for 14 days. After a healing time of 3–4 months, cement-retained single crowns and solely implant-supported fixed dental prostheses were fabricated and delivered to the patients. Outcome variables Survival criteria
The implant survival criteria were determined by the following: no clinical detectable implant mobility, no pain or any subjective sensation, no recurrent peri-implant infection,
At implant installation as well as after 1, 2, 4, 6, 8, and 12 weeks after surgery, resonance frequency analysis (RFA) measurements were taken by the OsstellTM mentor (Integration Diagnostics AB, Goteborg, Sweden). For each individual implant, a standardized abutment (SmartpegTM; Integration Diagnostics AB, Gamlestadvagen 3B, Goteborg, Sweden) was inserted and a transducer probe (OsstellTM mentor Probe II) was held to display the ISQ value. Three different directions (buccal, lingual, and occlusal) were detected at each observation time point, and a mean value of the three directions was applied for statistical analysis. Clinical assessment
The following clinical variables were recorded: modified plaque index (mPI), pocket probing depth (PPD), and modified bleeding index (mBI). All the measurements were taken by the same dentist using a periodontal probe (15 UNC/CP-11.5B Screening Color-Coded Probe, Hu-Friedy, Chicago, IL, USA). Radiographic assessment
Periapical radiographs were taken immediately after implant surgery, at 1-year, 3-year, and 5-year examination. For standardization, a paralleling technique with a Rinn film holder (XCP Instruments; Rinn Corporation Elgin, Elgin, IL, USA) was conducted. Radiographic analysis was conducted by a software program (SIDEXIS 1.12; Sirona Dental System GmbH, Bensheim, Germany). The following parameters were measured and averaged at the mesial and distal implants side: residual bone height (RBH), marginal bone level (MBL), and crestal bone loss (CBL) (Fig. 1). Radiographic assessments were conducted by two assistants who were not involved in this study. Follow-up assessment
The baseline assessment of radiographic parameters was performed immediately after implants placement. Patients were recalled at 12, 36, and 60 months after implant surgery. Implant complications, mPI, PPD, mBI, and radiographic analysis were performed during each visit (Mombelli et al. 1987; Muller et al. 2000). Radiographic analysis was conducted by two examiners (X.X.Z and X.Z) not involved in this study.
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Gu et al Transalveolar sinus floor elevation
measurements of two examiners showed high agreement. Implant survival
Twenty eight patients (13 women and 15 men) were enrolled in the study. Two patients were excluded because of membrane perforation according to the Valsalva maneuver test. Another patient was excluded because of refusal to attend the follow-up examination. Finally, 25 patients with 37 implants were included in the study. One implant lost 4 months after implant surgery and another lost 1 month after loading. 23 patients and 35 implants fulfilled the survival criteria, representing a 5-year cumulative survival rate of 94.6% at implant level and 92% at subject level. RFA measurements Fig. 1. Radiographic assessment. Reference lines were drawn as follows: (a) a line at most apical implant–bone contact at the mesial site or at the distal site; (b) a line at most coronal level of implant–bone contact at the mesial site or at the distal site; (c) a line at most coronal level of the implant shoulder. (a) Residual bone height (RBH): the distance between line (a) and line (b) at baseline; (b) marginal bone level (MBL): the distance between line (b) and line (c) at each visit; (c) crestal bone loss (CBL): an increase of MBL from each visit to baseline examination.
Statistical analysis
Data analysis was performed using a statistical software package STATA (version 11.0; StataCorp, College Station, TX, USA). The level of significance was set at a = 0.05. The interexaminer reliability was determined by intraclass correlation coefficient (ICC) for continuous variables (including RBH and CBL). The skewness and kurtosis test were used to test for normality of distribution of the data. Mean and standard deviation were calculated for quantitative variables to assess the clinical and radiographic parameters. The Friedman test was performed for the comparison of mBI, mPI, PPD, MBL, and CBL at different time point. Wilcoxon sign-rank test was performed for pairwise comparison of MBL and CBL at each time point. The Bonferroni correction was applied for correction of multiple testing, and the P-value was corrected by p/k (k, frequency of multiple testing).
Results Interexaminer agreement
Intraclass correlation coefficient (ICC) was 0.982 for RBH and 0.979 for MBL. The
One implant was lost 4 months after surgery. Thus, sequential RFA measurements were taken on 25 patients. The mean implant stability quotient (ISQ) values obtained at each time point are present in Table 1 and Fig. 2. At implant installation, the ISQ values ranged from 58.7 to 74, with a mean value of 70.1 (SD 5.15). The mean ISQ values decreased to 69.2 at 1 week and 68.3 at 2 weeks. The lowest mean ISQ value of 67.8 was reached at 4 weeks. Following this, the mean ISQ values increased to 70.1 at 6 weeks and 71.8 at 8 weeks. Between 8 and 12 weeks, the mean ISQ values increased to 72.8 finally. Clinical assessment
Table 2 shows the clinical parameters at each visit. All patients showed acceptable oral hygiene. The mBI was 0.63, 0.71, and 0.66 at 1-year, 3-year, and 5-year examination, respectively. The mPI was 0.34, 0.51, and 0.46 at 1-year, 3-year, and 5-year examination, respectively. The PPD was 3.03, 3.17, and 3.11 at 1-year, 3-year, and 5-year examination, respectively. No significant difference was found with the passage of time in all three parameters.
Table 1. Mean ISQ values at each time point N = 25
Mean
Median
SD
Baseline 1-week 2-week 4-week 6-week 8-week 12-week
70.1 69.2 68.3 67.8 70.1 71.8 72.8
71 70 69 69 71 72 73
5.15 4.01 4.84 4.42 2.93 2.59 2.54
ISQ, implant stability quotient.
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Fig. 2. Diagram visualizing the mean ISQ values at all observation periods.
Radiographic assessment
Table 3 shows the radiographic parameters at each visit. The RBH ranged from 1.7 to 3.8 mm, with a mean value of 2.81 mm (SD: 0.74 mm) in this study. The average MBL significantly increased from 1.56 mm at baseline to 2.39 mm (P < 0.001) at 1-year examination and 3.03 mm (P < 0.001) at 3year examination. The average MBL remained stable at years 3 and 5 (3.10 vs. 3.03 mm, P = 0.083). Thus, the average CBL significantly increased from 0.83 mm at 1year examination to 1.47 mm at 3-year examination (P < 0.001). The average CBL remained stable at years 3 and 5 (1.47 vs. 1.54 mm, P = 0.083). A visible radio-opaque structure could be detected in 47.2%, 42.9%, 37.1%, and 40% of the implants at baseline, 1-year, 3-year, and 5-year examination. At final examination, about 60% patients showed nearly 2-mm-high cloudy new bone formation. Slightly decreased bone height above the apex of the implants was found in about 15% patients. About 25% patients did not show obvious difference in endo-sinus bone height. Fig. 3 shows one typical example of all the subjects included in the study.
Discussion The aim of present study was to assess the clinical success of dental implants placed in severely atrophic maxilla (RBH ≤ 4 mm) using TSFE without grafting and evaluate the stability of cylindrical implants during the healing period. In this study, 25 patients with 37 implants were included. The average residual bone height was 2.81 mm. At 5-year follow-up, 23 patients and 35 implants fulfilled the survival criteria, representing a 5-year cumulative survival rate of 94.6% at implant level and 92% at subject level. This was in line with those reported by other studies (Winter et al. 2002; Nedir et al. 2009b, 2013). This indicated that
3 |
Clin. Oral Impl. Res. 0, 2014 / 1–6
Gu et al Transalveolar sinus floor elevation
Table 2. Summary of clinical parameters mean(median) ± SD 1-year (n = 23) 3-year (n = 23) 5-year (n = 23) Friedman test
mBI
mPI
PPD (mm)
0.63(1) 0.60 0.71(1) 0.71 0.66(1) 0.58 P = 0.40
0.34(0) 0.48 0.51(1) 0.51 0.46(0) 0.61 P = 0.25
3.03(3) 0.57 3.17(3) 0.75 3.11(3) 0.83 P = 0.40
mPI, modified plaque index; PPD, pocket probing depth; mBI, modified bleeding index.
Table 3. Summary of radiographic parameters mean(median) ± SD Baseline (n 1-year (n = 3-year (n = 5-year (n =
= 25) 23) 23) 23)
RBH (mm)
MBL (mm)
2.81(2.80) 0.74 – – –
1.56(1.49) 2.39(2.35) 3.03(2.52) 3.10(2.67)
CBL(mm)
0.27① 0.36② 0.96③ 0.94*④
– 0.83(0.82) 0.50⑴ 1.47(1.18) 1.02⑵ 1.54(1.26) 1.00*⑶
Friedman test: *significance P < 0.001. Wilcoxon sign-rank test: Significance (P < 0.008), ①
