This study evaluated the efficacy of implant supported dental restorations in patients with chronic periodontal diseases at various stages within 2 years of completing treatment. 30 patients with periodontal diseases and 30 patients without periodontal diseases were studied. Total counts of 276 implant bodies were divided into group A (patients with periodontal diseases; a total of 149 implants) and group B (patients with healthy periodontium; a total of 127 implants). In group A subjects, periodontitis was treated prior to implant placement. The study focused on patients’ modified sulcus bleeding index, modified plaque index, implant mobility index, periodontal probing depth and implant success rate 12 and 24 months after the completion of the treatment. The result show: there were no significant differences in implant success rate between groups A and B; modified sulcus bleeding index scores showed differences between the groups 24 months after treatment; there were no significant differences in other clinical indexes during the study between the groups; there were no significant differences in periodontal probing depth between the groups; modified plaque index and modified sulcus bleeding index were positively correlated in implant supported dental restoration patients with chronic periodontal diseases.
There have been controversies over whether dental implant therapy can achieve reliable clinical outcomes in patients with periodontal disease. Some argue that implant restoration might have a high failure rate in patients with periodontal disease; while Schou et al. demonstrated that the survival rates of suprastructures and implants were high in periodontitis-susceptible patients with sufficient infection control and maintenance. With the development of implant therapy technology, the related materials and procedures, implant therapy was frequently practiced in patients susceptible to periodontitis, but limited clinical outcome information was reported. In this study, the authors investigated the clinical outcomes of implant therapy in patients with chronic periodontitis compared to that in healthy subjects in order to explore the correlation between implant therapy success rate and periodontitis.
30 patients with chronic periodontitis and 30 healthy subjects who received dental implants were selected according to the inclusion criteria, accounting for 276 implants. The subjects were divided into two groups. Group A consisted of patients with chronic periodontitis (22 males and 18 females), with a total of 149 implants and average age of 37 years; Group B included healthy subjects without periodontitis (19 males and 21 females), with a total of 127 implants and average age of 42 years.
Inclusion criteria for the study included patients aged 18–50 years who met the general implantation conditions, with the application of delayed implantation and delayed restoration approach. Their bone structure had to be adequate for implantation. They had an applied fixed partial denture. Patients with chronic periodontitis underwent systematic diagnosis and treatment for periodontal disease before the implantation to ensure it was controlled for over 3 months without gum swelling and bleeding on probing during clinical examination. The subjects had to be healthy with good oral hygiene before the implantation, with no gum swelling, and bleeding on probing during clinical examination.
Exclusion criteria for the study included: patients with teeth adjacent to the implantation which were unhealthy; active aggressive periodontitis, periodontitis reflecting systemic diseases, periodontitis without improvement after treatment; bruxism; alcoholism, heavy smoking (more than 10 cigarettes a day); and patients with diabetes, severe osteoporosis or mental disorders.
At 6, 12, and 24 months post implantation, the subjects from both groups were examined using the modified sulcus bleeding index (mSBI), the modified plaque index (mPLI), the mobility index (MI), and their periodontal probing depth and general oral condition were assessed. Statistical analysis of the restoration success rate was conducted in these two groups. All of the above tests were done by the same operator.
A periodontal probe was used for determining the mSBI by gently probing at the gingival margin at a depth of about 1 mm. Bleeding and the extent of bleeding were observed: 0, no bleeding on probing; 1, spotted bleeding; 2, linear bleeding in the gingival sulcus; 3, severe bleeding. The values used for mPLI were: 0, no plaque; 1, plaque could be found when scratching the surface of implants with the probe; 2, visible plaque; 3, massive plague. Those for MI were: 0, no loosening; 1, mild buccolingual loosening <0.5 mm; 2, slight buccolingual loosening <1 mm but >0.5 mm; 3, buccolingual loosening >1 mm.
Probing depth was measured using a plastic probe with pressure control to the strength of 0.2 N to measure the distance between the gingival margin to the bottom of the periodontal pocket along the long axis of the tooth. Six measurements were taken at different spots, and the mean values were calculated.
Statistical analysis was performed using SPSS16.0. The two-sample Kolmogorov–Smirnov test (KS test) was used to compare the mSBI and mPLI indexes of the two groups; Student’s t test was used to compare the probing depth; χ 2 test was used to compare the implant success rate of the two groups; Kendall tau rank correlation was used to analyse the correlation with the clinical parameters.
After dental implant restoration, 6 implants came loose and eventually dropped off in group A, 1 occurred 2 months after the implant, 2 occurred 3 months after the implant, and 3 occurred 6 months after the implant. 3 implants came loose and dropped off in group B, 1 occurred 2 months after the implant, and 2 occurred 6 and a half months after the implant. 4 subjects in group A had mild swollen gums and bleeding on probing 24 months after implant; 2 subjects in group B had mild swollen gums and bleeding on probing. The remaining subjects had good oral health status. MI was 0 at all stages, and subjects were satisfied with the occlusal function after implant restoration.
Statistics showed that the success rate between the two groups had no significant difference ( P > 0.05) ( Table 1 ). mSBI showed no significant difference between the two groups at 6 and 12 months after the implant ( P > 0.05), but it was significantly different at 24 months ( P < 0.05) ( Table 2 ). mPLI showed no significant difference between the two groups at all stages ( P > 0.05) ( Table 3 ). Probing depth showed no significant difference between the two groups at all stages ( P > 0.05) ( Table 4 ). Kendall tau rank correlation analysis showed mPLI and mSBIs rank correlation coefficient r = 0.529 ( P < 0.01), indicating positive correlation between mPLI and mSBI.
|Groups||Survival||Failed||Survival rate||χ 2||P value|
|Stages||Z value||Associated probability|
|6 months||1.210||0.117 > 0.05|
|12 months||1.081||0.193 > 0.05|
|24 months||2.315||0.047 < 0.05|