Faculty Bibliography

BACKGROUND: The aim of the present clinical study was to determine the local bone density in dental implant recipient sites using computerized tomography (CT) and to investigate the influence of local bone density on implant stability parameters and implant success. METHODS: A total of 300 implants were placed in 111 patients between 2003 and 2005. The bone density in each implant recipient site was determined using CT. Insertion torque and resonance frequency analysis were used as implant stability parameters. The peak insertion torque values were recorded with OsseoCare machine. The resonance frequency analysis measurements were performed with Osstell instrument immediately after implant placement, 6, and 12 months later. RESULTS: Of 300 implants placed, 20 were lost, meaning a survival rate of %. 93.3 after three years (average 3.7 +/- 0.7 years). The mean bone density, insertion torque and RFA recordings of all 300 implants were 620 +/- 251 HU, 36.1 +/- 8 Ncm, and 65.7 +/- 9 ISQ at implant placement respectively; which indicated statistically significant correlations between bone density and insertion torque values (p < 0.001), bone density and ISQ values (p < 0.001), and insertion torque and ISQ values (p < 0.001). The mean bone density, insertion torque and RFA values were 645 +/- 240 HU, 37.2 +/- 7 Ncm, and 67.1 +/- 7 ISQ for 280 successful implants at implant placement, while corresponding values were 267 +/- 47 HU, 21.8 +/- 4 Ncm, and 46.5 +/- 4 ISQ for 20 failed implants; which indicated statistically significant differences for each parameter (p < 0.001). CONCLUSION: CT is a useful tool to determine the bone density in the implant recipient sites, and the local bone density has a prevailing influence on primary implant stability, which is an important determinant for implant success.

BACKGROUND: Dental implant placement requires precise planning with regard to anatomic limitations and restorative goals. The aim of this study was to evaluate the match between the positions and axes of the planned and placed implants using stereolithographic (SLA) surgical guides. METHODS: Ninety-four implants were placed using SLA surgical guides generated from computed tomography (CT) between 2005 and 2006. Radiographic templates were used for all subjects during CT imaging. After obtaining three-dimensional CT images, each implant was virtually placed on the CT images. SLA surgical guides, fabricated using an SLA machine with a laser beam to polymerize the liquid photo-polymerized resin, were used during implant placement. A new CT scan was taken for each subject following implant placement. Special software was used to fuse the images of the planned and placed implants, and the locations and axes were compared. RESULTS: Compared to the planned implants, the placed implants showed angular deviation of 4.9 degrees+/-2.36 degrees, whereas the mean linear deviation was 1.22+/-0.85 mm at the implant neck and 1.51+/-1 mm at the implant apex. Compared to the implant planning, the angular deviation and linear deviation at the neck and apex of the placed maxillary implants were 5.31 degrees+/-0.36 degrees, 1.04+/-0.56 mm, and 1.57+/-0.97 mm, respectively, whereas corresponding figures for placed mandibular implants were 4.44 degrees+/-0.31 degrees, 1.42+/-1.05 mm, and 1.44+/-1.03 mm, respectively. CONCLUSION: SLA surgical guides using CT data may be reliable in implant placement and make flapless implant placement possible.

Due to the angulation of maxillary bone as the maxillary bone resorption occurs from a buccal to palatal direction, bucco-lingually tilted implant placement is more likely especially in the posterior maxilla. The aim of this paper was to present a case restored by using a maxillary hybrid denture using Cresco method. A 59-year-old woman with an edentulous maxilla and five missing mandibular teeth was referred for implant treatment. Six months after sinus lift operation, four mandibular implants and six maxillary implants were placed. Due to the bucco-lingual tilt of two implants, the Cresco method was chosen to fabricate the metal framework for the maxillary hybrid denture that was delivered four months after implant placement. The main advantages of the Cresco method are a perfectly passive framework fit and corrected screw access holes. All ten implants placed were considered successful at 1-year recall, and no screw access holes were seen in the buccal part of the maxillary acrylic teeth. It was concluded that such screw-retained maxillary hybrid denture using the Cresco method met the esthetic expectations of a highly demanding patient.

The oral rehabilitation of cleft lip and palate (CLP) patients is challenging; and many of these patients are suffering because they received insufficient dental treatment. Several techniques, including surgeries, alveolar bone grafts, orthodontic appliances and advanced prosthodontic rehabilitation, have been proposed for the oral rehabilitation of CLP patients. This case report describes a maxillary overdenture that is supported by both teeth and soft tissue. Additional retention and stability have been obtained by a swing-lock attachment mechanism.

AIM: The aim of this study was to investigate the influence of three different thicknesses of In-Ceram core on the load at fracture of all-ceramic crowns. METHODS AND MATERIALS: Thirty standardized crown-shaped nickel-chromium alloy dies were fabricated using a milling machine. Twenty dies were prepared with a 1 mm shoulder for Groups A and B. The only difference in the ten dies used for Group C was a smaller 0.5 mm lingual shoulder. The thicknesses of In-Ceram were 0.5 mm, 1.5 mm, and 0.75 mm for Groups A, B, and C. All all-ceramic crowns were fabricated in accordance with the manufacturer's instructions. After cementation of the crowns, their fracture resistance was tested with a universal testing machine. The load was directed to a point located 3 mm from the lingual aspect of the incisal edge at 30 degrees to the long axis of each specimen until catastrophic failure occurred. RESULTS: The mean loads at fracture for Groups A, B, and C were 1117+/-388 N, 2083+/-385 N, and 1439+/-368 N, respectively. No statistically significant difference in load at fracture between Groups A and C was found (p>0.05). However, the differences were statistically significant between Groups A and B (p<0.001) and Groups B and C (p<0.001). CONCLUSION: Under the guidelines of this study, increasing the thickness of the In-Ceram core increased the fracture resistance of the all-ceramic crowns. CLINICAL SIGNIFICANCE: The sufficient thickness of the In-Ceram core of all-ceramic crowns is an important factor in fracture resistance. Therefore, dental practitioners should be careful in patient selection; if the horizontal overlap of a tooth to be restored is too limited, then all-ceramic crowns may not be a feasible option.

BACKGROUND: Further clarification of the early and late response of peri-implant tissues to surgical insertion and loading of dental implants and the potential associations among the various implant-related measures are likely to improve the evaluation/monitoring of implant sites. Thus, analyses were made of the volume and nitric oxide (NO) profile of peri-implant sulcus fluid (PISF), implant stability, and marginal bone level in relation to different prosthetic designs. METHODS: Seven totally edentulous subjects and 11 partially edentulous subjects were included. Resonance frequency analysis (RFA), marginal bone level measurements, PISF volume, and spectrophotometrically determined nitrite levels were analyzed comparatively at conventionally loaded (CL) implant sites and at implants with removable prostheses (RP; N = 14) and fixed prostheses (FP; N = 11) for a period of 12 months. RESULTS: At implant sites with RP, PISF volume decreased gradually and its lowest level occurred at the end of the experimental period. The PISF nitrite content increased until 6 months and was followed by a significant decrease at 12 months. Compared to baseline, RFA values exhibited a significant decrease at 1 and 3 months. Marginal bone level was significantly lower at all follow-up visits compared to baseline. More volumetric fluctuations of PISF was noted at implant sites with FP. The PISF nitrite content had decreased, compared to baseline, at 6, 9, and 12 months. A general stability was observed for RFA. The marginal bone loss observed at 6 months was followed by a gain at 12 months. An inverse relationship was noted between RFA values and marginal bone levels. CONCLUSION: The prosthetic design particularly seems to affect the NO metabolism around CL implants, whereas it does not seem to have any impact on the stability of dental implants.

BACKGROUND: Recent studies have showed that immediate/early loading of dental implants is a clinically feasible concept with results similar to those for standard two-stage procedures, especially in the mandible. However, there are only a few studies regarding the immediate/early loading of maxillary implants supporting single-tooth crowns. PURPOSE: The aim of this study was to compare the clinical and radiological outcomes of early- and delayed-loaded dental implants supporting single-tooth crowns in the maxilla. MATERIALS AND METHODS: Twenty-nine patients were consecutively treated between 2000 and 2002 with 59 Branemark System MK III TiUnite implants (Nobel Biocare AB, Goteborg, Sweden) in the maxilla. Two groups were formed according to the loading protocols. In the test group, definitive implant-supported single crowns were delivered to 19 patients 6 weeks after the implant placement. In the control group, definitive implant-supported single crowns were delivered to 10 patients 6 months after the implant placement. Clinical and radiographic parameters were recorded at baseline, 1 to 4 years. Implant stability measurements have only been performed at 4-year follow-up recall. RESULTS: Overall, three implants were lost during the study period. Two implants were lost in the test group including 36 implants, which indicated a survival rate of 94.4%. One of the lost implants was replaced and then osseointegrated successfully. One implant was lost in the control group during the healing period, which indicated a survival rate of 95.7%. The average marginal bone loss was 1.11 mm for 56 implants after 4 years. There were no significant differences in marginal bone levels, insertion torque, and resonance frequency values between the two groups. CONCLUSION: The results of this study indicate that 6 weeks of early loading period for TiUnite-surface titanium implants in the maxilla is reliable and predictable for this patient population and may offer an alternative to the standard loading protocol.

PURPOSE: The aim of the present study was to analyze the 2 molecular measures of inflammation: (1) the nitrite, an end metabolite of nitric oxide (NO) oxidation and (2) myeloperoxidase (MPO). Both are found in peri-implant sulcus fluid (PISF) of implants and gingival crevicular fluid (GCF) of natural teeth in healthy or diseased states. MATERIALS AND METHODS: A total of 109 tooth or dental implant sites, either healthy/noninflamed, inflamed (Gingival Index [GI] > 0), or affected by periodontitis, were classified, and GCF/PISF samples were obtained. GCF/PISF MPO and nitrite levels were spectrophotometrically determined. For comparison of clinical parameters and PISF/GCF nitrite and MPO levels, Kruskal-Wallis analysis followed by Mann-Whitney test with Bonferroni correction was performed. Healthy/noninflamed, slightly inflamed, moderate/severely inflamed sites were also analyzed using the Kruskal-Wallis test followed by the Mann-Whitney test with Bonferroni correction. The correlation between nitrite and MPO levels and clinical inflammatory status were analyzed with Spearman's correlation coefficient. RESULTS: Clinical parameters, including both the GCF and PISF volumes, demonstrated gradual increases with the presence of gingival/peri-implant inflammation (P < .05). Despite the higher PISF than GCF volume at healthy sites (P = .001), there were no volumetric differences at inflamed sites (P = .771). PISF from inflamed sites (P = .025) and GCF from gingivitis and periodontitis sites presented higher total MPO levels (P < .05) than samples from noninflamed sites. Despite the relatively stable GCF nitrite levels at healthy and diseased sites, PISF from inflamed sites had higher nitrite content than noninflamed sites (P < .05). CONCLUSIONS: The present study demonstrated the volumetric similarities of PISF and GCF in terms of response to inflammation. However, some differences between the 2 biochemical measures of inflammation and their presence in PISF and GCF were also observed. PISF is likely to have a considerable diagnostic potential for reflecting the biologic changes around load-bearing endosseous dental implants. (Cohort Study) (More than 50 references.)

BACKGROUND: During the assessments made at presurgical, surgical, and follow-up phases, the clinician may benefit from a wide array of clinical and/or image-based measures. Because analysis of the potential associations among the various measures could improve the evaluation process for dental implants, this study attempted to determine the potential correlations among peri-implant sulcus fluid (PISF) volume, implant stability, nitric oxide content of PISF, and marginal bone loss. METHODS: Seventeen completely edentulous patients seeking prosthetic rehabilitation were included. Two ball attachment mandibular overdentures were given to all patients, and early- (N = 18) and delayed-loaded (N = 16) dental implants were compared during 24-weeks of follow-up. Resonance frequency analysis (RFA), marginal bone level, and PISF samples were taken for all dental implants. RESULTS: A consistent and negative correlation was observed between RFA measurements and marginal bone level, whereas some correlations also existed between RFA and PISF volume. The pattern of loading seemed to affect the relationship between RFA measurements and marginal bone level and, to a limited extent, the association between PISF volume and nitrite levels. CONCLUSIONS: Where the potential associations among various implant-related measures are concerned, the factors that may affect such associations (e.g., healing and loading) need to be considered. Data arising from the analysis of the associations between the wide arrays of available implant-related measures may improve dental practitioners' assessment concerning endosseous dental implants.

AIMS: The objective of this study was to determine the relationship between bone density, insertion torque, and implant stability at implant placement. MATERIALS AND METHODS: One-hundred and eight patients were treated with 230 Branemark System implants. A computerized tomography (CT) machine was used for pre-operative evaluation of the jaw bone for each patient. The maximum insertion torque values were recorded with the OsseoCare equipment. Implant stability measurements were performed with the Osstell machine for only 142 implants. RESULTS: The mean bone density and insertion torque values were 721+/-254 Hounsfield unit (HU) and 39.1+/-7 N cm for 230 implants, and the correlation was significant (r=0.664, p<0.001). The mean bone density, insertion torque, and resonance frequency analysis values were 751+/-257 HU, 39.4+/-7 Nc m, and 70.5+/-7 implant stability quotient (ISQ), respectively, for 142 implants. Statistically significant correlations were found between bone density and insertion torque values (p<0.001); bone density and ISQ values (p<0.001); and insertion torque and ISQ values (p<0.001). CONCLUSION: The bone density values from pre-operative CT examination may provide an objective assessment of bone quality, and significant correlations between bone density and implant stability parameters may help clinicians to predict primary stability before implant insertion.