Surgical guides for flapless dental implant placement and immediate definitive prosthesis installation by using selective laser melting and sintering for 3D metal and polymer printing: A clinical report.

Integration between the phases of computer-based guided dental implant surgery can be used to optimize oral rehabilitation. Two new surgical guides prepared by using the 3D metal and polymer printing technology are presented for immediate implant loading and definitive fixed prosthesis construction in flapless dental implant surgery. Nine implants and 2 fixed prostheses were installed in 2 completely edentulous adult patients by using a metallopolymer surgical guide with a metal central bar attached to a polymer seal or a metal guide. Virtual planning was used to design the 3D-printed surgical guides, which were then constructed by using selective laser sintering (SLM) and selective laser melting (SLS). The 3D-printed surgical guides oriented the surgical placement of the implants and were welded to the abutments and attached to the denture framework. The technique allowed implants and prostheses to be installed on the same day.

A selective laser sintering prototype guide used to fabricate immediate interim fixed complete arch prostheses in flapless dental implant surgery: Technique description and clinical results.

STATEMENT OF PROBLEM: Extensive occlusal adjustments and misfit of the prosthesis to prosthetic components are frequent problems related to fixed interim prosthesis fabrication with immediate dental implant loading. PURPOSE: The purpose of this clinical trial was to evaluate a prosthetic guide made with a rapid prototype model based on virtual surgical planning. This prosthetic guide was used to fabricate fixed interim prostheses that would allow immediate implant loading after computer-guided implant installation. MATERIAL AND METHODS: Nine interim prostheses were made for 9 participants with complete maxillary or mandibular edentulism. The virtual prosthetic guide was planned using computer-assisted design (CAD) software and was fabricated with rapid prototyping equipment (selective laser sintering). The prosthetic guide had 3 portions: the occlusal portion, which had occlusal registration; the connection portion, which had the information of the position and angulation of the abutment/implant projection; and the mucosa portion, which had the registration of the alveolar mucosa architecture. The prosthetic guide was used by a dental technician to fabricate prostheses. A single trained examiner evaluated the passive fit of the interim prostheses, the average time required for installing the interim prosthesis and for occlusal adjustments, the satisfaction of the patient with the prosthesis; and the screws, torque, occlusion, and prosthesis status. RESULTS: Passive fit was achieved between the prosthetic components and prostheses in 7 participants. The average time required for installing the fixed interim prostheses was 64.44 minutes. All participants reported being more pleased with the fixed interim prosthesis than with the prosthesis worn before implant placement. Prosthesis fractures were observed in 3 participants (2 in the maxilla and 1 in the mandible); all fractures occurred 3 months or more after delivery. No further complication was observed during 6 months of follow-up. CONCLUSIONS: The prosthetic guide enabled fabrication of interim immediate prostheses that were easily seated and adjusted to accommodate any shifts in implant position occurring during computer-guided surgery. Immediate implant loading could be achieved in a reasonable operative time.

Mast Cells and Proteins Related to Myofibroblast Differentiation (PAR-2, IL-6, and TGFß1) in Salivary Cancers: A Preliminary Study.

Salivary gland neoplasms represent an important group of cancers in the head and neck and myoepithelial cells play a key role on the development these tumors. This study evaluated the distribution of mast cells and related proteins (PAR-2, TGFß1, IL-6) to the myofibroblastic differentiation in malignant tumors of salivary glands with and without myoepithelial differentiation. Immunohistochemical assessement for tryptase mast cells, SMA, PAR-2, TGFß1, IL-6 was performed in 10 cases of polymorphous low-grade adenocarcinoma, 14 cases of mucoepidermoid carcinoma (MEC) and 10 cases of adenoid cystic carcinoma. When the density of mast cells were compared between tumors, their density was significantly higher in MEC (P=0.08). Tumors with high expression of PAR-2 (79.4%) exhibited a high density of mast cells. Myofibroblasts were more frequent in malignant tumors with low expression (<50%) of cell masts. Individual analysis of the tumors showed no significant difference between the expression of PAR-2, IL-6, TGFß1, and myofibroblasts. When the density of mast cells, myofibroblasts and the expression of PAR-2 protein, IL-6, and TGFß1 were compared, it was no statistically significant difference between tumors with and without myoepithelial differentiation. The results of present study suggest a possible participation of mast cells and especially of PAR-2 in the development and progression of malignant salivary cancers, regardless of myoepithelial content.

Evaluation of the effect of tumor necrosis factor-alpha gene polymorphism on the risk of peri-implantitis: a case-control study.

PURPOSE: Tumor necrosis factor-alpha (TNFalpha) is a proinflammatory cytokine, which promotes bone resorption and mediates the inflammatory response to infection. Because implant failures appear to cluster in subsets of individuals, this phenomenon may be related to gene polymorphisms. Therefore, the aim of this study was to investigate the relationship between a specific polymorphism in the TNFalpha gene (allele 2 of TNFalpha(-308)) and peri-implantitis. MATERIALS AND METHODS: This case-control study included Caucasian nonsmoking Brazilian patients with implant-supported restorations. Oral epithelial cells were taken from patients with and without peri-implantitis to evaluate the frequencies of different alleles of the TNFalpha(-308) gene by polymerase chain reaction. RESULTS: Ninety patients (49 with peri-implantitis and 41 with healthy implants) were enrolled in this study. Polymorphism in allele 2 of TNFalpha(-308) was not associated with an increased risk for peri-implantitis (P = .8171), although 14.63% of the subjects in the control group carried allele 2 and 19.39% in the peri-implantitis group carried allele 2 (chi-squared = 0.708; P = .5202). CONCLUSION: Polymorphism of the TNFalpha(-308) gene was not associated with an increased risk of peri-implantitis in the population evaluated in this study.

Antigen-presenting cells in human immunosuppressive drug-induced gingival enlargement.

An immunoperoxidase technique was used to compare the number of CD1a+ and factor XIIIa+ dendritic cells (DCs), and CD68+ Macrophages (M) in 30 gingival samples from subjects with clinically healthy periodontitium (HP) and 10 samples from subjects with drug-induced gingival enlargement (DIGE). Fewer CD1a+ and factor XIIIa+ DCs were found in areas with inflammatory infiltration (II) of the lamina propria (LP) in the group with immunosuppressed DIGE (IDIGE) compared to the group with HP. In the sulcular and junctional/pocket epithelia, the number of CD1a+ DCs was decreased in the group with IDIGE (p<0.05). There was a tendency toward a reduced number of CD1a+ DCs and CD68+ M in areas without inflammatory infiltrate of the LP in the group with IDIGE. The alterations in the number of antigen-presenting cells (APCs) may be the reason for the decreased periodontal inflammation and breakdown clinically observed in subjects who are immunosuppressed.

Effect of meloxicam and diclofenac sodium on peri-implant bone healing in rats.

BACKGROUND: This study evaluated the effects of diclofenac sodium and meloxicam on peri-implant bone healing. METHODS: Thirty male rats were divided into three groups: the control group (CG) received no drug; the diclofenac sodium group (DSG) received 1.07 mg/kg twice a day for 5 days; and the meloxicam group (MG) received 0.2 mg/kg daily for 5 days. A screw-shaped titanium implant was placed in the tibia. Fluorochromes, oxytetracycline (OxT), calcein (CA), and alizarin (AL), were injected at 7, 14, and 21 days, respectively, after implantation, and the animals were sacrificed 28 days after implant placement. The percentages of OxT-, CA-, and AL-labeled bone as well as the percentages of bone-to-implant contact (BIC), cortical bone area (CBA), and trabecular bone area (TBA) within the implant threads were evaluated. RESULTS: Bone healing was delayed in the DSG during the first 14 days after implant placement (OxT-labeled bone: DSG: 5.3% +/- 7.3% versus CG: 13.2% +/- 9.8%, P = 0.002, and versus MG:14.4% +/- 13.1%, P = 0.05). The percentages of BIC (DSG: 49.6% +/- 21.9%; MG: 67.1% +/- 22.8%; and CG: 68.1% +/- 22.8%) and CBA (DSG: 63.7% +/- 21.2%; MG: 82.7% +/- 12.4%; CG: 84.9% +/- 10.6%) were lower in the DSG compared to the MG and CG (P <0.001). The percentage of TBA was significantly greater in the DSG compared to the MG and CG (DSG: 36.3% +/- 21.2% versus MG: 17.3% +/- 12.7% and versus CG: 15.1% +/- 10.6%; P <0.001). CONCLUSION: Diclofenac sodium seemed to delay peri-implant bone healing and to decrease BIC, whereas meloxicam had no negative effect on peri-implant bone healing.

A finite element analysis of two different dental implants: stress distribution in the prosthesis, abutment, implant, and supporting bone.

This study evaluates the influence of 2 commercially available dental implant systems on stress distribution in the prosthesis, abutment, implant, and supporting alveolar bone under simulated occlusal forces, employing a finite element analysis. The implants and abutments evaluated consisted of a stepped cylinder implant connected to a screw-retained, internal, hexagonal abutment (system 1) and a conical implant connected to a solid, internal, conical abutment (system 2). A porcelain-covered, silver-palladium alloy was used as a crown. In each case, a simulated, 100-N vertical load was applied to the buccal cusp. A finite element model was created based on the physical properties of each component, and the values of the von Mises stresses generated in the prosthesis, abutment, implant, and supporting alveolar bone were calculated. In the prostheses, the maximum von Mises stresses were concentrated at the points of load application in both systems, and they were greater in system 1 (148 N/mm2) than in system 2 (55 N/mm2). Stress was greater on the abutment of system 2 than of system 1 on both the buccal (342 N/mm2 x 294 N/mm2) and lingual (294 N/mm2 x 148 N/ mm2) faces. Stress in the cortical, alveolar bone crest was greater in system 1 than in system 2 (buccal: 99.5 N/mm2 x 55 N/mm2, lingual: 55 N/mm2 x 24.5 N/mm2, respectively). Within the limits of this investigation, the stepped cylinder implant connected to a screw-retained, internal hexagonal abutment produces greater stresses on the alveolar bone and prosthesis and lower stresses on the abutment complex. In contrast, the conical implant connected to a solid, internal, conical abutment furnishes lower stresses on the alveolar bone and prosthesis and greater stresses on the abutment.

Association Between Mast Cells and Collagen Maturation in Chronic Periodontitis in Humans.

Mast cells (MCs) can influence the maturation of collagen fibers. This study evaluated the relationship between the distribution and degranulation of MCs and collagen maturation in human gingival tissue in chronic periodontitis. A total of 16 specimens of patients clinically diagnosed as periodontitis and 18 controls clinically diagnosed as healthy or gingivitis were included. Immunohistochemistry and Picrosirius staining were performed to identify MCs and assess collagen fibers, respectively. Chi-square, t test, and Pearson's correlation test ( p<0.05) were used. In control specimens, there was a positive association between MCs in the connective tissue and the presence of immature collagen ( p=0.001); in periodontitis samples, this association was not confirmed ( p≥0.12). There was no significant relationship between periodontal diagnosis and collagen maturation or MC degranulation ( p≥0.35). MC density was significantly higher ( p=0.04) in periodontitis tissue (339.01 ± 188.94 MCs/mm2) than in control tissue (211.14 ± 131.13 MCs/mm2) in the area of connective tissue containing inflammatory infiltrate. There was a correlation between the number of MCs and probing depth ( r = 0.34, p=0.04). MCs are involved in the pathogenesis of periodontal diseases and might be associated with collagen maturation in periodontal tissue during the early stages of periodontal disease pathogenesis.

Association between alcohol dependence and both periodontal disease and tooth loss: a cross-sectional study.

The impact of alcohol consumption on periodontal disease and tooth loss is still under debate. The aim of this cross-sectional study was to evaluate the association between alcohol dependence and both periodontal diseases and tooth loss in Brazilian native Indians. Full mouth periodontal examination was performed and tooth loss was clinically evaluated in a representative sample of 225 Indians (≥ 19 years). Sociodemographic, oral health-related data, and alcohol dependence were evaluated using structured questionnaires. The subjects were categorized as either alcohol-dependent or non-dependent according to the Alcohol Use Disorders Identification Test results. Severe periodontal disease was defined in individuals with ≥ 2 proximal sites with a clinical attachment level ≥ 6 mm, not on the same tooth, and ≥ 1 proximal site with a probing depth ≥ 5 mm. Tooth loss was categorized as one or more missing teeth, or no missing teeth. Bivariate models followed by logistic regression were used to assess the association between alcohol dependence and both periodontal disease and tooth loss. Prevalence ratio (PR) was calculated using Mantel-Haenszel analysis. Alcohol dependence increased 2.5 times the risk for tooth loss (prevalence ratio [PR] =2.49, 95% confidence interval [CI] = 1.01-9.04, p = 0.05). Severe periodontal disease was not associated with alcohol dependence (OR = 0.54, 95% CI = 0.22-1.31, p = 0.23). In conclusion, alcohol dependence was associated with tooth loss in the present population, but severe periodontal disease was not. Questions on alcohol dependence should be included in dental anamnesis questionnaires, and patients diagnosed with alcohol dependence should be referred for dental evaluation.

Root coverage in isolated gingival recessions using autograft versus allograft: a pilot study.

BACKGROUND: Different surgical techniques have been used to treat gingival recessions. This preliminary study compared clinical findings for the treatment of isolated gingival defects using a coronally positioned flap associated with a subepithelial connective tissue graft or an acellular dermal matrix graft. METHODS: Ten subjects with bilateral and comparable Miller Class I or II defects were selected. The defects were > or =3.0 mm deep and were assigned randomly to the test group, which was treated with a coronally positioned flap associated with an acellular dermal matrix, or to the control group, which was treated with a coronally positioned flap associated with a subepithelial connective tissue graft. Probing depth (PD), clinical attachment level (CAL), gingival recession depth (GRD), and width (KT) and thickness (GT) of the keratinized tissue were assessed at baseline and 6 months after the surgery. RESULTS: Mean root coverage was 50% in the test group (representing a gingival margin shift of 2.1 +/- 0.99 mm) and 79.5% in the control group (representing a gingival margin shift of 3.5 +/- 1.20 mm). These results were statistically different on intra- and intergroup comparisons (P <0.05). Between-group comparisons revealed statistically significantly greater gains in CAL, GRD, and GT in the control group (P < or =0.05); no differences were found for PD or KT (P > or =0.05). CONCLUSIONS: The coronally positioned flap associated with a subepithelial connective tissue graft or an acellular dermal matrix graft was effective in root coverage. However, the coronally positioned flap associated with a connective tissue graft provided a more favorable clinical outcome. More expanded studies are needed to confirm the present findings.

Hydrocortisone affects the expression of matrix metalloproteinases (MMP-1, -2, -3, -7, and -11) and tissue inhibitor of matrix metalloproteinases (TIMP-1) in human gingival fibroblasts.

BACKGROUND: There is a positive correlation between the course of periodontal disease and psychosocial stress status. Stress leads to activation of the hypothalamic-pituitary-adrenal axis, resulting in increased cortisol release. The present study evaluates the effect of two different hydrocortisone concentrations on mRNA expression of matrix metalloproteinases (MMPs) and tissue inhibitor of matrix metalloproteinases (TIMPs) in cultured, human gingival fibroblasts. METHODS: Gingival fibroblasts were stimulated with 10(-7) or 10(-9) M hydrocortisone for 24 hours; untreated cells served as controls. Alterations in the expression of MMP-1, -2, -3, -7, -11 and TIMP-1 and -2 were evaluated using real-time polymerase chain reaction and Western blotting. beta-actin mRNA expression was used as a reference to normalize gene expression. RESULTS: Although the higher hydrocortisone concentration upregulated MMP-1, -2, -7, -11, and TIMP-1 (P <0.05) expression, the lower concentration induced downregulation or diminished upregulation. The lower hydrocortisone concentration induced a 23-fold increase in MMP-3 gene expression, whereas the higher concentration induced less upregulation; however, protein expression was regulated similarly by both hydrocortisone concentrations. The effect of hydrocortisone on TIMP-2 expression was not significant (P >0.05). CONCLUSIONS: Hydrocortisone produced a dose-dependent regulation of MMP and TIMP expression. The higher hydrocortisone concentration significantly upregulated expression of MMP-1, -2, -7, and -11 and TIMP-1 in human gingival fibroblasts, which may constitute a mechanism underlying the increased periodontal breakdown associated with psychosocial stress status.

Peri-implant bone loss around posterior mandible dental implants placed after distraction osteogenesis: preliminary findings.

BACKGROUND: The present study evaluates implant survival and peri-implant bone loss around posterior mandible dental implants placed at sites of distraction osteogenesis. METHODS: On removal of the distraction devices, 34 dental implants were inserted into 14 posterior mandible sites in 10 healthy, non-smoking female patients. Prosthetic treatment was performed 4 months after implant placement using fixed implant prostheses. After 6 to 16.5 months, periapical radiographs were taken and evaluated for peri-implant bone loss and radiolucency. The distance between the implant margin and the first visible bone-implant contact was measured on the mesial and distal aspects of the implants using imaging software. Radiographic dimensional distortion was corrected as a function of the known true dimension of the implant. RESULTS: Of the 34 implants placed, two (5.9%) failed to integrate at reentry surgery. Both were replaced and restored during the course of the study so that a total of 34 implants was followed for 12.1 +/- 3.8 months post-restoration and 16.1 +/- 3.8 months post-insertion. Mean loss of marginal bone height was 2.6 +/- 1.0 mm. During the follow-up period, radiolucent lines along the implant surface were absent. CONCLUSIONS: The mean peri-implant bone loss in areas of alveolar bone distraction was 1.9 mm/year. A high implant survival rate was observed.

Use of anorganic bovine-derived hydroxyapatite matrix/cell-binding peptide (P-15) in the treatment of class II furcation defects: a clinical and radiographic study in humans.

BACKGROUND: This study compared clinical and radiographic findings for the treatment of Class II furcation defects in human mandibular molars using anorganic bovine-derived hydroxyapatite matrix (ABM)/cell-binding peptide (P-15) or open flap debridement (OFD). METHODS: Twelve subjects showing two comparable Class II furcation defects in their mandibular molars were enrolled. The defects in each subject were assigned randomly to the test (ABM/P-15) or the control (OFD) group. Clinical measurements and standardized radiographs were taken at baseline and 6 to 7 months after surgery. RESULTS: There were no statistically significant differences between the test and control groups for any clinical or radiographic parameter (P >0.05). On comparing the baseline and final measurements, the gain in horizontal clinical attachment level and reduction in gingival recession were significant only in the test group (P < or =0.02), whereas the gain in the vertical clinical attachment level was significant in both groups (P < or =0.04). In the test group, four of 12 sites showed complete closure, and five showed partial closure; in the control group, three defects showed complete closure, and four showed partial closure (P = 0.42). Subtraction radiography revealed similar gains in bone height and increases in mean bone density with both treatments (P >0.05). CONCLUSIONS: ABM/P-15 yielded favorable results in the treatment of Class II furcation defects over a 6-month evaluation period; however, there was no difference compared to OFD. Further studies using a larger sample size are needed to confirm the present findings.

The effect of epidermal growth factor on matrix metalloproteinases and tissue inhibitors of metalloproteinase gene expression in cultured human gingival fibroblasts.

OBJECTIVE: Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) play a role in the breakdown of the extracellular matrix during normal physiological processes, and in pathological processes, including periodontitis. The aim of this study was to evaluate the effect of epidermal growth factor (EGF) on the expression of MMPs and TIMPs in cultured human gingival fibroblasts. METHODS: Fibroblasts were stimulated with 10(-3), 10(-6) or 10(-12)M EGF for 24h; untreated fibroblasts served as controls. Alterations in the expression of MMP-1, 2, 3, 7, 11, TIMP-1 and 2 were evaluated using real-time PCR and Western blotting. beta-Actin expression was used as a reference to normalize gene expression. RESULTS: Increased MMP-1, 3, 7 and 11 expressions were observed at all EGF concentrations (p<0.05). At the lowest EGF concentration, MMP-1, 3 and 7 presented the lowest expression and MMP-11 presented the greatest expression; at higher EGF concentrations, MMP-1, 3 and 7 presented greater up-regulation, and MMP-11 lower up-regulation (p<0.05). Protein expression was similarly regulated by EGF: increased up-regulation of MMP-1, 3 and 7 was observed with increasing EGF concentrations, except for MMP-11 that exhibited greater up-regulation at the lower EGF concentration. The gene expression of MMP-2, TIMP-1 and 2 was not affected by EGF (p<0.05). CONCLUSIONS: We conclude that EGF regulates expression for MMP-1, 3, 7 and 11 in a dose-dependent manner, suggesting that EGF may play a role in periodontal destruction and wound repair.

Dental health status in crack/cocaine-addicted men: a cross-sectional study.

The aim of this study was to evaluate the association between crack/cocaine addiction and dental health in men. Forty crack/cocaine-addicted patients and 120 nonaddicted patients (≥18 years) underwent full-mouth dental examinations. Decayed, missing, and filled teeth (DMFT) were identified using the criteria recommended by the World Health Organization. Crack/cocaine addiction was determined, based on the medical records and interviews of each patient. All drug-addicted patients used both crack and cocaine. The chi-square test and logistic regression analysis were used to assess the association between DMFT and crack/cocaine addiction (p ≤ 0.05). Decayed teeth showed a positive association with crack/cocaine addiction (odds ratio (OR) = 3.65; 95% confidence interval (CI), 1.68-7.92; p = 0.001), whereas filled and missing teeth showed a negative association (filled teeth: OR = 0.37; 95% CI, 0.18-0.76; p = 0.008; missing teeth: OR = 0.33; 95% CI, 0.13-0.81; p = 0.02). The DMFT was only associated with age (OR = 2.12; 95% CI, 1.11-4.08, p = 0.023). In the present population, crack/cocaine addiction was associated with a greater decayed teeth index and a lower filled and missing teeth index. Programs aimed to encourage self-esteem and encourage individuals to seek dental care are required for this population. Further studies using a larger sample size and studies with women are required to confirm the results.

Modified coronally advanced flap associated with a subepithelial connective tissue graft for the treatment of adjacent multiple gingival recessions.

BACKGROUND: The clinical choice of the appropriate surgical technique aiming at root coverage relies, among other factors, on the number of adjacent gingival recessions. This study aimed to clinically evaluate the effectiveness and the predictability of root coverage at adjacent multiple gingival recessions using a modified coronally positioned flap associated with the subepithelial connective tissue graft. METHODS: Ten non-smoking, healthy subjects (five men and five women; mean age, 28.7 years) presenting 29 Class I or II adjacent multiple gingival recessions were enrolled. Each patient was treated using a modified coronally advanced flap associated with the subepithelial connective tissue graft. Probing depth (PD), clinical attachment level (CAL), recession depth (RD), and width of keratinized tissue (KT) were measured at baseline and 6 months later. The Student t test was used to compare treatment outcomes through time. RESULTS: The results revealed significant CAL gain (mean gain +/- SD, 1.97 +/- 0.94 mm; P <0.0001), RD decrease (2.03 +/- 0.78 mm; P <0.0001), and KT increase (1.31 +/- 1.23 mm, P <0.0001). The average root coverage was 96.7%, and complete root coverage was found at 93.1% of the defects. Nine of the 10 patients (90% of the patients) experienced complete root coverage. CONCLUSIONS: The modified coronally advanced flap associated with the subepithelial connective tissue graft was effective and predictable to produce root coverage at multiple adjacent gingival recessions associated with gain in the CAL and in the width of KT.

Association of dental infections with systemic diseases in Brazilian Native Indigenous: a cross-sectional study.

The aim of this cross-sectional study was to evaluate the association between dental infections and systemic diseases in the Indigenous population of Brazil. A representative sample of 225 Indigenous (≥19 years) was assessed. The T-test and bivariate and logistic models were used to assess the associations of diabetes, hypertension, and obesity with dental caries and destructive periodontal disease. After adjustments for covariates, dental caries were associated with hypertension (odds ratio = 1.95; 95% confidence interval: 1.03-3.66; P = .04). Individuals with destructive periodontal disease had a higher systolic blood pressure (124 ± 20.34 mm Hg) than those without destructive periodontal disease (117.52 ± 16.54 mm Hg; P = .01). In conclusion, dental infections were found to be associated with hypertension in the present population. Thus, patients diagnosed with hypertension should be referred for dental evaluation and vice versa.

Posterior mandibular alveolar distraction osteogenesis utilizing an extraosseous distractor: a prospective study.

BACKGROUND: The aim of this clinical study was to evaluate bone elongation and the effectiveness of distraction osteogenesis when utilizing an extraosseous distractor to treat cases of atrophic posterior mandible. METHODS: Fourteen surgical sites were evaluated in 10 healthy, non-smoking, female patients, with varying degrees of atrophic posterior mandible, who underwent surgery by alveolar bone distraction. The patients presented between 6 and 10 mm above the mandibular, inferior alveolar nerve. Panoramic radiographs were taken before surgery and at the beginning and end of the consolidation period. The extraosseous distractor was fixed to both the basal and the osteotomized bone. After a 7-day latency period, the patients rotated the distractor rod three times a day for 3 to 10 days (1 mm per day). The mobile segment was held in place for 8 to 12 weeks for bone consolidation. RESULTS: The results revealed a distraction range of 2.32 to 8.11 mm (mean distraction +/- standard deviation, 5.12 +/- 1.67 mm), which was less than the real, measured distance between the upper and lower miniplates of the distractor (5.58 +/- 1.62 mm). The bone segments showed between 0.03 and 2.53 mm (mean, 0.88 +/- 0.59 mm) resorption above the upper miniplate. The efficacy of the extraosseous distractor was calculated as between 30.41% and 94.58% (73.45% +/- 20.32%). CONCLUSIONS: Bone regeneration was obtained in all cases; however, when planning alveolar bone distraction using the extraosseous distractor, greater distraction should be performed to compensate for the inclination of the distractor rod and possible bone loss. This adjustment should increase the efficacy of distraction osteogenesis.

Clinical application of stereolithographic surgical guides for implant placement: preliminary results.

BACKGROUND: The success of implant-supported restorations requires detailed treatment planning, which includes the construction of a surgical guide. Recently, computer-aided rapid prototyping has been developed to construct surgical guides in an attempt to improve the precision of implant placement. The aim of the present study was to evaluate the match between the positions and axes of the planned and placed implants when a stereolithographic surgical guide is employed. METHODS: Six surgical guides used in four patients (three women, one man; age from 23 to 65 years old) were included in the study and 21 implants were placed. A radiographic template was fabricated and computer-assisted tomography (CT) was performed. The virtual implants were placed in the resulting 3-dimensional image. Using a stereolithographic machine, liquid polymer was injected and laser-cured according to the CT image data with the planned implants, generating three surgical guides, with increasing tube diameters corresponding to each twist drill diameter (2.2, 3.2, and 4.0 mm), for each surgical area. During the implant operation, the surgical guide was placed on the jawbone and/or the teeth. After surgery, a new CT scan was taken. Software was used to fuse the images of planned and placed implants, and the locations and axes were compared. RESULTS: On average, the match between the planned and the placed implant axes was within 7.25 degrees +/- 2.67 degrees ; the differences in distance between the planned and placed positions at the implant shoulder were 1.45 +/- 1.42 mm, and 2.99 +/- 1.77 mm at the implant apex. In all patients, a greater distance was found between the planned and placed positions at the implant apex than at the implant head. CONCLUSIONS: Clinical data suggest that computer-aided rapid prototyping of surgical guides may be useful in implant placement. However, the technique requires improvement to provide better stability of the guide during the surgery, in cases of unilateral bone-supported and non-tooth-supported guides. Further clinical studies, using greater number of patients, are necessary to evaluate the real impact of the stereolithographic surgical guide on implant therapy.

Comparison between subtraction radiography and conventional radiographic interpretation during long-term evaluation of periodontal therapy in Class II furcation defects.

BACKGROUND: Limited information comparing digital subtraction radiographic assessment with conventional radiographic interpretation is available from longitudinal clinical trials. The aim of this study was to evaluate the ability to detect periodontal bone changes during the long-term maintenance of Class II furcation defects by conventional radiographic interpretation compared to interpretation of digital subtraction images. METHODS: Standardized radiographs of 18 Class II furcation defects in mandibular molars were taken at baseline and at 6, 12, 18, and 24 months after non-resective periodontal surgery. Conventional radiographic and digital subtraction interpretations were performed masked, respectively, by two and three experienced examiners, according to the following categories: bone gain; bone loss; unchanged appearance; and impossible to visualize. Percent concordance and the kappa statistic value (kappa) were computed. RESULTS: Conventional radiographic and digital subtraction interpretation images resulted in 72 decisions for each examiner. The visual interpretation of digital subtraction images by two examiners revealed the same results. The interpretation of conventional radiographic images showed a low concordance between examiners (kappa < 0.40) at all examinations. The concordance between subtraction radiography and conventional radiographic interpretation was also low for all examiners (kappa < 0.36) at all examinations. Using subtraction radiography as a reference, bone changed and bone unchanged were diagnosed correctly in 47.2% of cases by examiner A, in 43.1% by examiner B, and in 38.9% by examiner C. CONCLUSION: It can be concluded that conventional radiographic interpretation is a more subjective and inaccurate method of detecting periodontal bone changes in Class II furcation defects in mandibular molars when compared with subtraction radiography.