The positive effect of tenting screws for primary horizontal guided bone regeneration: A retrospective study based on cone-beam computed tomography data.

OBJECTIVES: To radiographically evaluate the effect of the adjunctive use of tenting screws (TS) for primary horizontal guided bone regeneration (GBR). MATERIALS & METHODS: Twenty-eight patients in need of staged bone augmentation were consecutively treated in a private practice. A xenogenic particulate bone substitute material (DBBM) and a resorbable collagen membrane were used in all patients. Subjects were divided into two groups: control (conventional GBR; n = 22) and test (tenting screws in conjunction with GBR - TS; n = 22). CBCT images were obtained before augmentation and after 6-8 months. CBCTs were superimposed, and linear horizontal measurements were performed. Alveolar ridge width (RW) and ridge width change (RWchange) were assessed at 1, 3, 5, and 7 mm below the bone crest. RESULTS: Forty-four sites in 28 patients were evaluated. No differences between the groups were detected for RW at baseline (TS: 5.87 ± 2.41; control: 5.36 ± 1.65). Regarding RWchange, TS promoted an additional effect at 1 and 3 mm below the crest compared to control (p < .05; RWchange-1 TS: 3.72 ± 2.46; control: 1.25 ± 3.05; RWchange-3 TS: 3.98 ± 2.53; control: 2.50 ± 2.02). The final RW was greater in group TS compared to the control group at the 1, 3, and 5 mm level (p < .05). CONCLUSIONS: The use of tenting screws exerted a positive effect on staged GBR with a greater final RW at the 3 mm level. In addition, GBR in conjunction with TS was able to provide consistent bone augmentation at lingual/palatal sites.

Deproteinized bovine bone mineral is non-inferior to deproteinized bovine bone mineral with 10% collagen in maintaining the soft tissue contour post-extraction: A randomized trial.

OBJECTIVES: To test the non-inferiority of demineralized bovine bone mineral (DBBM) compared to demineralized bovine bone mineral with 10% collagen (DBBM-C) for the maintenance of the soft tissue contour after tooth extraction in the esthetic zone. MATERIAL AND METHODS: Sixty-five patients randomly received ridge preservation at a single site in the anterior maxilla with DBBM or DBBM-C. Both, DBBM and DBBM-C, were covered with a collagen matrix. Profilometric analyses were performed at baseline (BL), immediately after treatment (PO), and at 4 months (FU; day of implant placement). The main outcome was the horizontal mean change (HC) at the buccal aspect. The measurements also included changes of the estimated soft tissue thickness (eTT) at 1, 3, and 5 mm below the buccal gingival margin. Descriptive analysis was performed, and differences between groups were analyzed using independent samples t test. The non-inferiority test was performed for HC. RESULTS: At 4 months, the horizontal mean change (HC) was -1.43 mm (±0.53 mm) (DBBM-C) and -1.32 mm (±0.53 mm) (DBBM). Change of the estimated soft tissue thickness (eTT) between baseline (BL) and four months of follow-up (FU) at 1, 3, and 5 mm amounted to -4.58 mm (±2.02 mm), -2.40 mm (±0.97 mm), and -1.37 mm (±0.78 mm) for DBBM-C and to -4.12 mm (±1.80 mm), -2.09 mm (±0.91 mm), and -1.23 mm (±0.72 mm) for DBBM. The differences between the groups were not statistically significantly for any of the outcome measures (p > .05). CONCLUSIONS: DBBM is non-inferior to DBBM-C for the maintenance of the soft tissue contour 4 months after tooth extraction.

Root Coverage for Single Deep Gingival Recessions: Outcomes Based on a Decision-Making Algorithm.

AIM: The aim of this study is to report root coverage outcomes in single deep gingival recessions (GR) following a proposed decision-making algorithm. MATERIALS AND METHODS: A retrospective, practice-based study included single deep (≥5 mm) Miller Class II and III defects. The step-by-step decision-making algorithm led to a choice among three different flap designs (coronally advanced flap (CAF), double papilla envelope flap (DPE) or modified lateral sliding flap (LSF)) used with a connective tissue graft. Recession depth (RD) at 6 months follow-up and the corresponding root coverage (RC) were the primary outcomes assessed. RESULTS: Sixteen GR defects were included, with baseline RD of 6.7 ± 1.8 mm. Six months postoperatively, RD was significantly reduced to 1.2 ± 0.8 mm (p < 0.05). Mean RC was 81.7 ± 13.0%, without significant differences between Miller Class II (87.1 ± 9.2%; n=9) and Class III (74.6 ± 14.5%; n=7) GRs (p=0.07). Postoperatively, keratinized tissue width increase was greater for LSF (3.5 ± 1.1) and DPE (4.2 ± 1.4 mm) than for CAF (1.9 ± 0.9 mm). CONCLUSIONS: Following the proposed decision-making algorithm, root coverage outcomes for GR defects ≥5 mm were comparable to outcomes reported for shallow defects. Prospective clinical trials are needed to validate the proposed approach and techniques. PRACTICAL IMPLICATIONS: The proposed algorithm allows the clinician to select the appropriate surgical technique for treatment of single deep gingival recessions with good predictability.

Profilometric changes of peri-implant tissues over 5 years: A randomized controlled trial comparing a one- and two-piece implant system.

OBJECTIVES: To assess the profilometric changes of the buccal soft tissues between baseline and 5 years of loading using a one- and two-piece dental implant system. MATERIALS AND METHODS: Sixty patients randomly received dental implants of either a two-piece type (BRA) or a one-piece type (STM). Casts were obtained at baseline (after crown insertion), at the 1-year and at the 5-year follow-up. Stereolithography files were obtained from the casts for digital superimposition. One implant and the contralateral natural tooth were selected for the analysis. Thirty-three patients (BRA = 16; STM = 17) were included. Measurements included changes for crown height (CH) and estimated soft tissue thickness, as well as the profilometric change at the implant and the tooth site. Nonparametric methods were applied for the statistical analyses and medians and quartiles presented. RESULTS: The BRA group lost -0.39 mm and the STM group lost -0.40 mm of volume between baseline and the 5-year follow-up at the implant site (p > 0.05). The tooth site lost -0.18 mm (BRA) and -0.12 mm (STM) (p > 0.05). Volume differences between implants and teeth amounted to -0.05 mm (baseline to 1 year) and -0.25 mm (baseline to 5 years) for BRA, while for STM, the values were 0.03 mm (baseline to 1 year) and -0.16 mm (baseline to 5 years). The changes for implant CH at 1 and 5 years of follow-up amounted 0.10 and 0.09 mm (BRA) and to 0.03 and 0.22 mm (STM). The changes in tissue thickness at 1 and 5 years in the BRA group amounted to -0.28 and -0.66 mm at 1 mm, -0.21 and -0.46 mm at 3 mm, and -0.32 and -0.45 mm at 5 mm, respectively. The changes in the STM group amounted to -0.15 and -0.54 mm at 1 mm, -0.24 and -0.48 mm at 3 mm, and -0.32 and -0.57 mm at 5 mm, respectively. No significantly different medians were observed. CONCLUSIONS: Minimal profilometric and linear changes occurred at implant sites between baseline and 5 years, between implant and tooth sites and between the two implant systems.

Impact of cannabis sativa (marijuana) smoke on alveolar bone loss: a histometric study in rats.

BACKGROUND: Cannabis sativa (marijuana) can interfere with bone physiopathology because of its effect on osteoblast and osteoclast activity. However, its impact on periodontal tissues is still controversial. The present study evaluates whether marijuana smoke affects bone loss (BL) on ligature-induced periodontitis in rats. METHODS: Thirty male Wistar rats were used in the study. A ligature was placed around one of the mandible first molars (ligated teeth) of each animal, and they were then randomly assigned to one of two groups: control (n = 15) or marijuana smoke inhalation ([MSI] for 8 minutes per day; n = 15). Urine samples were obtained to detect the presence of tetrahydrocannabinol. After 30 days, the animals were sacrificed and decalcified sections of the furcation area were obtained and evaluated according to the following histometric parameters: bone area (BA), bone density (BD), and BL. RESULTS: Tetrahydrocannabinol was positive in urine samples only for the rats of the MSI group. Non-significant differences were observed for unligated teeth from both groups regarding BL, BA, and BD (P >0.05). However, intragroup analysis showed that all ligated teeth presented BL and a lower BA and BD compared to unligated teeth (P <0.05). The intergroup evaluation of the ligated teeth showed that the MSI group presented higher BL and lower BD (P <0.05) compared to ligated teeth from the control group. CONCLUSION: Considering the limitations of this animal study, cannabis smoke may impact alveolar bone by increasing BL resulting from ligature-induced periodontitis.

Histometric evaluation of bone around titanium implants with different surface treatments in rats exposed to cigarette smoke inhalation.

OBJECTIVES: There is a lack of histological information about the influence of cigarette smoke on bone around surface-treated implants. The aim of the present study was to test the influence of titanium surface treatment on osseointegration in animals that were exposed to intermittent cigarette smoke inhalation. MATERIAL AND METHODS: Twenty-two male Wistar rats were used. One tibia, chosen at random, received a machined titanium implant (MI) while the other received an aluminum oxide-blasted surface implant (ABI). The animals were randomly assigned to one of the following groups: Group 1 - control (n=11) and Group 2 - intermittent cigarette smoke inhalation (n=11). Sixty days after surgery, the animals were sacrificed. The degree of bone-to-implant contact (BIC), bone filling (BF) within the limits of the threads of the implants and bone density (proportion of mineralized bone in a 500-mum-wide zone lateral to the implant - BD) were measured in the cortical (zone A) and cancellous bone (zone B) areas. RESULTS: Data analysis showed significant differences when comparing the groups and implant surfaces in both zones for BIC (two-way ANOVA -P<0.05). The two groups presented higher BIC mean values for ABI, when compared with MI (P<0.05). In group 2, cigarette smoke inhalation negatively affected BF in both zones (P<0.05). Group 2 presented a significantly decreased BD in both zones (P<0.05). No statistically significant differences were observed between surfaces in any of the groups for BD. CONCLUSION: Within the limits of the present study, it can be concluded that the aluminum oxide blast surface treatment may increase the degree of BIC but cannot overcome the detrimental effect of tobacco smoke on bone around titanium implants.

Cannabis sativa smoke inhalation decreases bone filling around titanium implants: a histomorphometric study in rats.

PURPOSE: Although the harmful effect of tobacco smoking on titanium implants has been documented, no studies have investigated the effects of cannabis sativa (marijuana) smoking. Thus, this study investigated whether marijuana smoke influences bone healing around titanium implants. MATERIALS: Thirty Wistar rats were used. After anesthesia, the tibiae surface was exposed and 1 screw-shaped titanium implant was placed bilaterally. The animals were randomly assigned to one of the following groups: control (n = 15) and marijuana smoke inhalation (MSI) 8 min/d (n = 15). Urine samples were obtained to detect the presence of tetra-hidro-cannabinoid. After 60 days, the animals were killed. The degree of bone-to-implant contact and the bone area within the limits of the threads of the implant were measured in the cortical (zone A) and cancellous bone (zone B). RESULTS: Tetra-hidro-cannabinoid in urine was positive only for the rats of MSI group. Intergroup analysis did not indicate differences in zone A-cortical bone (P > 0.01), however, a negative effect of marijuana smoke (MSI group) was observed in zone B-cancellous bone for bone-to-implant contact and bone area (Student's t test, P < 0.01) values. CONCLUSIONS: Considering the limitations of the present study, the deleterious impact of cannabis sativa smoke on bone healing may represent a new concern for implant success/failure.

Low- and high-yield cigarette smoke inhalation potentiates bone loss during ligature-induced periodontitis.

BACKGROUND: It is well recognized that cigarette consumption is a strong risk factor for periodontitis. Tobacco companies have developed a cigarette with low levels of toxic compounds; however, its effect on periodontium has not been investigated. The aim of this study was to verify the impact of smoke produced by low- and high-yield cigarettes on bone loss resulting from ligature-induced periodontitis. METHODS: A total of 36 male Wistar rats were used in the study. A ligature was placed around one of the mandibular first molars (ligated teeth) of each animal, and they were assigned randomly to one of three groups: group 1: control (N = 10), group 2: 30 days' inhalation of smoke produced by high-yield cigarettes (N = 13), and group 3: 30 days' inhalation of smoke produced by low-yield cigarettes (N = 13). The animals were sacrificed 30 days after ligature placement, and the specimens were processed for decalcified sections. RESULTS: Intergroup analysis of unligated teeth (without periodontal disease) did not show a significant difference regarding periodontal ligament area (2.40 +/- 0.5 mm(2), 2.72 +/- 0.7 mm(2), and 2.61 +/- 0.4 mm(2) for groups 1, 2, and 3, respectively; P >0.05). Conversely, significant differences were noted in ligated teeth (with periodontitis); bone loss was directly proportional to the level of toxic compounds in the cigarettes (5.74 +/- 0.5 mm(2), 7.40 +/- 0.50 mm(2), and 6.51 +/- 0.50 mm(2) for groups 1, 2, and 3, respectively; P <0.05). CONCLUSION: Low- and high-yield cigarettes potentiated bone loss during experimental periodontitis in a directly proportional fashion.

Smoking modulates interferon-gamma expression in the gingival tissue of patients with chronic periodontitis.

Although interferon-gamma (IFN-gamma) plays a critical role in periodontitis, no information is available regarding the effect of smoking on this cytokine in the periodontium. Therefore, this study aimed to evaluate the effect of smoking on the IFN-gamma levels in gingival tissue from patients with chronic periodontitis. Sixty-two patients were assigned to three groups: healthy [non-smoking and periodontally healthy individuals (probing depth or= 5 mm and bleeding on probing; n = 25)]; and smoking [smokers (>or= 1 pack/day for at least 10 yr) diagnosed with chronic periodontitis (n = 25)]. Gingival biopsies were analyzed by quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. Regardless of smoking status, diseased patients presented higher levels of IFN-gamma than peridontally healthy patients. In sites with comparable types of periodontitis, smoking increased both protein and mRNA levels of IFN-gamma in gingival tissue. Within the limits of this study, it can be concluded that modulation of periodontal tissue destruction by smoking may involve its effect on IFN-gamma production.

Selective cyclooxygenase-2 inhibitor may impair bone healing around titanium implants in rats.

BACKGROUND: The aim of this study was to investigate the effect of a selective cyclooxygenase-2 inhibitor, meloxicam, on bone healing around titanium implants in rats. METHODS: Thirty-one adult male Wistar rats were included in this study, and one screw-shaped titanium implant was inserted in the tibiae of each rat. The animals were randomly assigned to one of the following groups for daily subcutaneous injections: control (N = 14): saline solution; and test (N = 17): 3 mg/kg of meloxicam, each administered daily for 60 days. After the treatment, animals were sacrificed, and undecalcified sections were obtained. Bone-to-implant contact (BIC) and bone area (BA) within the limits of implant threads and bone density (BD) in a 500 mum-wide zone lateral to the implants were obtained and arranged for cortical (zone A) and cancellous (zone B) bone regions. RESULTS: Intergroup comparisons demonstrated that meloxicam significantly reduced bone healing around implants. For zone A, significant differences were observed regarding BIC (47.01 +/- 10.48 A; 35.93 +/- 12.25 B), BA (86.42 +/- 3.66 A; 61.58 +/- 12.09 B), and BD (96.86 +/- 0.96 A; 91.06 +/- 3.05 B) for control and test groups, respectively (P <0.05). For zone B, data analysis also showed significant differences among groups for BIC (30.76 +/- 13.80 A; 16.86 +/- 11.48 B), BA (34.83 +/- 8.18 A; 25.66 +/- 9.16 B), and BD (15.76 +/- 7.05 A; 7.73 +/- 4.61 B) for control and test groups, respectively (P <0.05). CONCLUSION: Meloxicam may negatively influence bone healing in the cortical and cancellous bone around titanium implants inserted in rats after continuous administration.

Bone density around titanium implants may benefit from smoking cessation: a histologic study in rats.

PURPOSE: This study tested the hypothesis that interruption of cigarette smoke inhalation (CSI) would reverse its impact on bone quality around implants. MATERIALS AND METHODS: Sixty-nine rats were assigned to 1 of 4 groups. Group 1 (n = 16) was the control group; group 2 experienced CSI for the duration of the study (150 days); group 3 experienced CSI for 83 days prior to implant placement, until 7 days prior to implant placement, when CSI ceased; and for group 4, CSI exposure was temporarily halted from 7 days before implantation to 21 days afterward. Bone density (the proportion of mineralized bone in a 500-microm-wide zone lateral to the implant) was calculated for each specimen (mean +/- SD). RESULTS: In the cortical bone, a slight difference in bone density was noted between the groups (97.66% +/- 3.69% for group 1, 98.30% +/- 0.95% for group 2, 98.83% +/- 0.73% for group 3, and 98.11% +/- 1.14 for group 4; P > .05). In contrast, continuous exposure to cigarette smoke (group 2) significantly decreased density in the cancellous bone in comparison to the other groups (25.69% +/- 9.41% for group 1, 18.08% +/- 6.0% for group 2, 25.46% +/- 5.42 for group 3, and 26.20% +/- 6.77% for group 4; P < .05), with no significant differences between groups 1, 3, and 4 (P > .05). DISCUSSION: The results support the concept that the effects of cigarette consumption on dental implants may be reversible, and therefore suggest that smokers may realize satisfactory outcomes if they cease smoking, even temporarily. CONCLUSION: In conclusion, smoking may affect bone quality around titanium implants in cancellous bone, and cessation could result in a return toward to the levels of the control group.

Bone filling around titanium implants may benefit from smoking cessation: a histologic study in rats.

BACKGROUND: Although a harmful effect of smoking on titanium implants has been documented, only a few studies have investigated the benefits of smoking cessation. Thus, this study histologically investigated whether smoking cessation influences bone healing around titanium implants and comparatively evaluated temporary versus complete cessation protocols. METHODS: Sixty-six male Wistar rats were randomly assigned to one of four groups: control (N = 16); CSI, intermittent cigarette smoke inhalation (CSI) throughout the entire 150-day experiment (N = 17); P-CSI, CSI 83 days prior to implant placement (N = 17); or R-CSI, CSI for 83 days, cessation 7 days before and 21 weeks after implant placement, and return to CSI for 39 days (N = 16). The animals were sacrificed and the degree of bone-to-implant contact (BIC) and the bone area (BA) within the limits of the implant threads obtained for cortical (zone A) and cancellous bone (zone B). RESULTS: Intergroup analysis (Kruskal-Wallis test, alpha = 0.05) demonstrated a significant effect of CSI on BA (P <0.05) and that temporary or complete CSI cessation protocols resulted in values similar to those of the control group (P >0.05) 88.91% +/- 4.29%; 80.66% +/- 6.55%; 84.27% +/- 6.96%; 85.71% +/- 4.7% in zone A, and 51.28% +/- 6.49%; 38.69% +/- 10.78%; 48.87% +/- 8.47%; 49.47% +/- 8.04%; in zone B for groups CTRL, CSI, P-CSI, and R-CSI, respectively. CONCLUSION: Within the limits of the present investigation, temporary and complete CSI cessation reversed the effect of smoke exposure on bone healing around titanium implants in both cortical and cancellous bone.

Smoking cessation may present a positive impact on mandibular bone quality and periodontitis-related bone loss: a study in rats.

BACKGROUND: It has been previously shown that cigarette smoke inhalation (CSI) enhances bone loss in ligature-induced periodontitis. In this study, the hypothesis that the interruption of smoke exposure would reverse the impact of CSI on mandibular bone quality and periodontitis-related bone loss was tested. METHODS: Fifty-three Wistar rats were randomly assigned to one of the following groups: group 1: control, N = 16; group 2: 83 days of CSI prior to ligature placement, N = 17; or group 3: 90 days of CSI before and 60 days after ligature placement, N = 20. Animals were sacrificed 60 days after ligature placement, the jaws removed and immediately radiographed for photodensitometry analysis. Bone loss was histometrically evaluated. RESULTS: CSI did not affect unligated sites in either condition (P >0.05); however, smoke inhalation during the whole experimental period significantly enhanced bone loss in ligated teeth (P < 0.05). Moreover, similar levels of bone loss were observed for ligated teeth between the control and cessation groups (0.90 +/- 0.33 mm(2); 0.96 +/- 0.32 mm(2); 1.64 +/- 0.65 mm(2); groups 1, 2 and 3, respectively). Radiographically, continuous exposure to cigarette smoke promoted a significantly reduced bone density (1.74 +/- 0.38 aluminum equivalence [Al eq]; 1.74 +/- 0.14 Al eq; and 0.68 +/- 0.10 Al eq for groups 1, 2, and 3, respectively). CONCLUSIONS: Within the limits of the present investigation, it can be assumed that CSI may enhance bone loss in ligature-induced periodontitis, and negatively impact mandibular bone quality. Additionally, smoke exposure cessation seems to reverse its impact on mandibular bone, and, therefore, may be of clinical relevance.

Effect of estrogen and calcitonin therapies on bone density in a lateral area adjacent to implants placed in the tibiae of ovariectomized rats.

BACKGROUND: This study evaluated the influence of estrogen and calcitonin administration on tibial bone density in a lateral area adjacent to implants placed in ovariectomized rats (OVX). METHODS: One screw-type titanium implant was placed bilaterally in the ovariectomized rats, and the animals assigned to one of the following groups: group 1 (n = 15): sham surgeries; group 2 (n = 15): OVX; group 3 (n = 14): OVX subcutaneously administered with calcitonin (CT) 4 days/week (16 IU/kg); group 4 (n = 14): OVX administered daily with 17beta estradiol (20 microg/kg). After 60 days, the animals were sacrificed and undecalcified sections obtained. Blood samples were collected to measure serum levels of alkaline phosphatase and calcium at the time of sacrifice. Bone density was measured in a 500 microm wide mineralized zone lateral to the implant. RESULTS: Alkaline phosphatase levels in groups 2 and 3 (P > 0.05) were statistically higher than groups 1 and 4 (P < 0.05), and calcium serum levels were higher in group 2 than the other groups (P < 0.05). Regarding bone density, the data were grouped separately for cortical (zone A) and cancellous (zone B) bone. In zone A, intergroup analysis revealed no significant difference among groups (P > 0.05). However, in zone B, the animals that received estrogen administration (group 4) presented a higher bone density than groups 2 and 3 (P < 0.05). CONCLUSION: It appears that estrogen therapy may prevent the negative influence of endogenous estrogen deficiency on bone density around titanium implants placed in ovariectomized rats.

A comparative study on the effect of nicotine administration and cigarette smoke inhalation on bone healing around titanium implants.

BACKGROUND: A series of isolated studies has focused on the influence of smoking on bone around titanium implants. This study proposes to investigate the impact of two conditions, i.e., nicotine administration and cigarette smoke inhalation, on the healing around implants. METHODS: Forty-five Wistar rats were used. After anesthesia, the tibiae surface was exposed and a screw-shaped titanium implant was placed bilaterally. The animals were randomly assigned to one of the following groups: Group 1: control, n = 19; Group 2: intermittent cigarette smoke inhalation, n = 15; and Group 3: subcutaneous administration of nicotine (3 mg/kg) twice daily, n = 11. After 60 days, the animals were sacrificed. The degree of bone-to-implant contact (BIC) and the bone area (BA) within the limits of the threads of the implant were measured in the cortical (zone A) and cancellous bone (zone B) areas. RESULTS: In zone A, cigarette smoke presented a significant negative influence on BIC and BA (Kruskal-Wallis test, P < 0.05). In contrast, the administration of nicotine did not influence either parameter (P > 0.05). In zone B, cigarette smoke inhalation also resulted in a decreased percentage of BIC compared to the control group (P < 0.05). In addition, the BA was significantly decreased in groups 2 and 3 when compared to controls (P > 0.05). CONCLUSION: The negative impact of smoking on implant outcomes may be related to more than one molecule present in the cigarette smoke and nicotine seems to partially contribute, especially in the cancellous bone.