Effect of implant design on survival and success rates of titanium oral implants: a 10-year prospective cohort study of the ITI Dental Implant System

AIM: The aim of this 10-year study (observation time 8-12 years, mean: 10 years) was to compare the survival rates, success rates and incidences of biological complications using three different implant designs of the ITI Dental Implant System. MATERIAL AND METHODS: In 89 dental patients treated comprehensively, a total of 112 hollow screw (HS), 49 hollow cylinder (HC) and 18 angulated hollow cylinder (AHC) implants were installed depending on the available bone volume and according to prosthetic needs. One and 10 years after surgical placement, clinical and radiographic parameters were assessed. The incidences of peri-implantitis according to various thresholds were registered over 10 years of maintenance. RESULTS: Success criteria at 10 years were set at: pocket probing depth (PPD)< or =5 mm, bleeding on probing (BoP)-, bone loss < 0.2 mm annually. The survival rate for HS was 95.4%, for HC 85.7% and for AHC 91.7%. Ninety percent of all the HS, 71% of the HC and 88% of the AHC did not present with an incidence of peri-implantitis over the 10 years, HC having significantly higher incidence of peri-implantitis than HS (P< 0.004). With the success criteria set above, a success rate for HS of 74%, for HC of 63% and for AHC of 61% was identified at 10 years. However, including a definition of PPD< or =6 mm, BoP - and bone loss < 0.2 mm annually for success, the rates for HS were 78%, for HC 65% and for AHC 67%, respectively. Basing success criteria purely on clinical parameters (without radiographic analysis), such as: PPD< or =5 mm and BoP-, the success rates increased to 90%, 76% and 89%, respectively. With PPD< or =6 mm and BoP - as success criteria chosen, the respective rates were 94%, 82% and 94% for HS, HC and AHC implants, respectively. CONCLUSIONS: A significantly higher survival rate as well as a significantly lower incidence of peri-implantitis was identified for hollow screw design ITI Dental Implants after 10 years of service when compared to hollow cylinder design ITI Dental Implants (95.4% vs. 85.7%; 10% vs. 29%). Depending on the setting of the threshold criteria for success, success rates are highly variable and hence, reporting of success rates with elaboration on the criteria set appears crucial for comparison of different studies.     

Clinical and microbiological effects of different restorative materials on the periodontal tissues adjacent to subgingival class V restorations

OBJECTIVES: The relationship between subgingival dental restorations and periodontal health has been thoroughly investigated for many years. However, longitudinal data on the subgingival microflora features after the placement of well-finished subgingival restorations are still lacking. Therefore, this study compares the short-term clinical and microbiological features occurring in the gingiva after the completion of different subgingival restorations. MATERIAL AND METHODS: Sixteen systemically healthy subjects, 10 males and six females (ages: 31.7-45.8 years; mean age 39.3+/-5.1 years), who were non-smokers and were positive for the presence of three cervical abrasion/erosion defects to be restored in three different adjacent teeth were enrolled in this study. The cervical abrasion/erosion defects were each restored by using one of three different materials: amalgam, glass ionomer cement, or composite resin. Immediately before class V cavity preparations and restorations (baseline), clinical monitoring and subgingival plaque sampling were performed in the mid-buccal aspect of each experimental restored tooth and in one adjacent sound, non-treated, control tooth. These procedures were repeated every 4 months over the following 1 year. RESULTS: Throughout the study, the clinical parameters recorded did not change significantly in any of the experimental groups, and no differences were detected among them at each clinical session. Over this time, no significant changes in the composition of the subgingival microflora were observed in amalgam, glass ionomer cement, and control groups. Conversely, in the composite resin group, there was a significant increase in the total bacterial counts, and a significant (p<0.05) decrease in Gram-positive, aerobic bacteria, which was associated with a significant (p<0.05) increase in the Gram-negative, anaerobic microbiota. CONCLUSIONS: Over a 1-year observation period, amalgam, glass ionomer cement, and composite resin subgingival restorations do not significantly affect the clinical parameters recorded. However, composite resin restorations may have some negative effects on the quantity and quality of subgingival plaque.     

GTR treatment of intrabony defects in patients with early-onset and chronic adult periodontitis

Young, systemically healthy subjects may suffer from early-onset forms of periodontitis characterized by the presence of localized deep vertical bony defects. The aim of this study was to compare the healing response after guided tissue regeneration (GTR) treatment of similar intrabony defects in patients affected by early-onset and chronic adult periodontitis. Twenty systemically healthy, nonsmoking subjects were enrolled in the study; 10 were affected by early-onset periodontitis (EOP) and 10 by chronic adult periodontitis (CAP). In each subject, only one deep vertical bony defect (intrabony component > 4 mm, probing attachment level > or = 8 mm) was treated according to the principles of GTR therapy with titanium-reinforced e-PTFE membranes. At the time of the surgery and at the 1-year follow-up, a microbiologic test for the identification of the main periodontopathogens was performed in each of the treated sites. There was no statistically significant difference at 1 year in the amount of clinical attachment gain (P = .4), reduction of probing pocket depth (P = .3), or increase in gingival recession (P = 1.0) between EOP and CAP patients. The 1-year microbiologic results demonstrated the complete disappearance of the putative periodontopathogens from all surgically treated sites in both patient groups. The results of the study demonstrated that deep intrabony defects in patients with EOP can be successfully treated by means of GTR procedures and that the suppression of periodontopathogens under threshold values can be maintained for at least 1 year, provided that the patient is enrolled in a maintenance program consisting of recalls for professional tooth cleaning and reinforcement of self-performed oral hygiene measures at 1-month intervals.     

Nine-year results following treatment of intrabony periodontal defects with an enamel matrix derivative: report of 26 cases

Treatment of intrabony periodontal defects with an enamel matrix derivative (EMD) has been demonstrated, in the short term, to result in periodontal regeneration and to significantly improve clinical parameters such as probing depth (PD) and clinical attachment level (CAL). The present study evaluated deep intrabony defect sites at 9 years after treatment with EMD. Twenty-one patients with a total of 26 deep intrabony defects with PD > or = 6 mm and intrabony depth > or = 3 mm, as identified by probing and radiographs, were consecutively treated with EMD. PD, recession of the gingival margin (GR), and CAL were evaluated prior to treatment and at 1 and 9 years after treatment. At 1 year, mean PD was significantly reduced. At 9 years, mean PD was statistically significantly increased versus the 1-year results but still significantly improved versus baseline. After I year, mean GR had increased significantly; at 9 years, measurements showed statistically significant improvements compared to the 1-year results and baseline. The mean CAL changed from 10.0 +/- 2.3 mm at baseline to 6.8 +/- 2.3 mm at 1 year and to 7.0 +/- 1.9 mm at 9 years. No treated teeth were lost during the observation period. The clinical improvements obtained following treatment with EMD can be maintained over a period of 9 years.     

Immunohistochemical analysis of collagen fibrils within the hybrid layer: a FEISEM study

This study evaluated the immunohistochemical labeling pattern of dentin collagen fibrils within hybrid layers created by different bonding systems using high resolution SEM. Four different adhesive materials, including self-etching and total-etching systems, were examined: Prime & Bond NT, OptiBond SOLO Plus, Single Bond and Clearfil Protect Bond. All materials were applied to the dentin of extracted human third molars. After cutting the bonded specimens transversely, an anti-collagen type I antibody was incubated on the surface of the dentin-adhesive interface and gold-conjugated secondary antibody was applied to reveal collagen labeling under high resolution SEM. The hybrid layers showed a significant number of collagen fibrils embedded in the resin matrix. The presence of exposed dentin collagen fibrils, as determined by positive labeling with an anti-type I collagen monoclonal antibody, is considered an indication of the presence of incompletely embedded fibrils and, thus, the quality of dentin matrix hybridization. The hybrid layers produced by total-etching systems showed higher labeling compared to those produced by the self-etching system. Positive collagen labeling was also found along the resin tags produced by total-etching adhesive systems.     

The papilla amplification flap for the treatment of a localized periodontal defect associated with a palatal groove

BACKGROUND: Teeth with a palatal groove often present with severe localized periodontal attachment loss including pocket formation and alveolar bone loss. The aim of the present case report was to describe the regenerative surgical treatment of periodontal and bone lesions associated with the subgingival extension of a palatal groove affecting a maxillary lateral incisor. METHODS: The left maxillary lateral incisor of a systemically healthy young subject presented with a palatal probing depth of 10 mm with no gingival recession at the buccal and palatal surfaces; the neighboring interdental papillae were intact. The radiograph showed a radiolucency area distal to the affected tooth. Treatment procedures consisted of: 1) the papilla amplification flap with the use of enamel matrix proteins as the regenerative periodontal material; 2) the elimination/flattening of the radicular portion of the palatal groove; and 3) the sealing of the coronal portion of the groove with composite flow. RESULTS: The clinical examination at 1 year revealed a clinical attachment gain (8 mm) with a shallow residual probing depth (2 mm) and no increase in gingival recession. The radiographic examination showed the complete disappearance of the radiolucency area suggesting bone fill. CONCLUSIONS: The present study indicated that localized periodontal defects associated with a palatal groove can be successfully treated by means of the papilla amplification flap with the use of enamel matrix protein as the regenerative material. The long-term stability of such successful results needs to be determined.     

Efficacy of bisphosphonates for the control of alveolar bone loss in periodontitis

Periodontal disease is characterized by periodontal bone loss. For this reason, we conducted a study to test the effect of alendronate (ALN), an inhibitor of bone resorption, on alveolar bone mass. A total of 335 patients with periodontal disease (men = 162, women = 173), aged 30 to 79, were randomized to either placebo or ALN 70 mg once weekly. All patients received prophylaxis at baseline, and at 6, 12, and 18 months. Smokers accounted for 62% of patients, and 71% of the patients had severe periodontal disease. The primary efficacy endpoint was the change in alveolar bone loss (ABL). When all subjects were analyzed, 2 years of treatment with alendronate 70 mg once weekly did not significantly change either ABL or alveolar bone density (ABD) relative to placebo. However, in the subgroup of patients with low mandibular bone mineral density (BMD) at baseline, alendronate significantly reduced bone loss relative to placebo (p < 0.01). No such effect was seen in patients with normal baseline mandibular BMD. The overall and upper gastrointestinal safety and tolerability profile of alendronate after 2 years of treatment was very favorable compared to placebo. No cases of osteonecrosis of the jaw were observed. In summary, in patients with periodontal disease receiving prophylaxis, alendronate 70 mg once weekly was well tolerated, but did not have a detectable effect on alveolar bone loss, except in those patients with low mandibular BMD at baseline.     

Effect of pre-cure temperature on the bonding potential of self-etch and self-adhesive resin cements.

OBJECTIVES: To assess whether the pre-cure temperature of resin cements significantly influenced the bonding potential to dentin. METHODS: Forty extracted molars were randomly divided into 8 groups (n=5): Groups (1-4) RelyX Unicem (RU, 3 M ESPE) and Groups (5-8) Panavia F 2.0 (PF, Kuraray Co.), at pre-cure temperatures of 4, 24, 37, and 60 degrees C, respectively. Cements were used in dual-cure mode for luting composite overlays (Paradigm MZ100, 3 M ESPE) to dentin. Microtensile bond strength testing and scanning electron microscope (SEM) observations of cement-dentin interfaces were performed. RESULTS: Group 4 had to be eliminated as RU at 60 degrees C underwent such an accelerated curing that was already set at the time of dispensing. The bond strengths (MPa) measured at refrigerator, room, and intraoral temperature were, respectively: RU 5.4+/-1.7, 11.4+/-6.1, 10.6+/-4.2; PF 7.4+/-3.7, 13.9+/-6.2, 12+/-5.2. The statistical analysis revealed that both luting agents developed a significantly weaker adhesion when used at refrigerator temperature (p<0.05). No statistically significant differences in bond strength were recorded when either cement was used at 24 or 37 degrees C (p>0.05). Pre-heating of PF to 60 degrees C resulted in a significant increase in bond strength (20.7+/-9.4 MPa; p<0.05). SEM observations disclosed an enhanced potential of PF to form a hybrid layer as the temperature increased over 4 degrees C. RU exhibited a less porous and more homogeneous layer at intraoral than at refrigerated temperature. SIGNIFICANCE: It is advisable to let refrigerator-stored resin cements warm up to at least room temperature prior to clinical use. Pre-heating to 60 degrees C enhances the bonding potential of PF.     

Osseous resective surgery: long-term case report

This case report evaluated the long-term effects of osseous resective therapy in the treatment of a patient with moderately advanced periodontal disease. In 1984, the patient underwent initial therapy followed by a periodontal surgical phase consisting of osseous recontouring with an apically positioned flap. After 20 years, in 2003, the patient presented with a traumatic complication. An exploratory surgery revealed a fracture on the roof of the pulp chamber on the maxillary left first molar. The buccal roots were resected, preserving the palatal root, and a reevaluation of the long-term outcome of osseous resective surgery was performed. It is suggested that the positive treatment result is the consequence of the reestablishment of tissue morphology favorable for oral hygiene and plaque control by the patient.     

Five-year changes in periodontal parameters after apical surgery

Introduction

Most clinical studies on the outcome of apical surgery concentrate on periapical healing based on radiographic and clinical characteristics (signs and symptoms). This study focuses on long-term changes in periodontal parameters after apical surgery.

Methods

Periodontal parameters (ie, probing depth [PD], level of gingival margin [GM], and calculated clinical attachment level [CAL]) were collected at baseline and at 1 and 5 years after apical surgery. Changes in PD, GM, and CAL were calculated over time and were also evaluated in relation to patient-, tooth-, and treatment-related covariables.

Results

One hundred eighty-six of 242 initially identified teeth could be evaluated. Significant changes in GM and CAL were observed at facial sites during the first year after surgery (mean recession of GM was 0.29 mm, mean CAL loss was 0.20 mm), but none of the periodontal parameters significantly changed between 1 and 5 years after apical surgery. With regard to covariables, the type of incision technique was found to be the major factor affecting changes in GM and CAL between baseline and 1 year after surgery. Age, smoking, and type of periapical healing were the variables influencing the periodontal parameters over the longer observation period of up to 5 years.

Conclusions

Patients should be informed about possible changes in periodontal parameters (gingival recession and loss of attachment) after apical surgery. The surgery itself appears to account for changes observed during the first year, whereas patient- and healing-related factors seem to affect periodontal changes seen thereafter.