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PubMed1998

Guided bone regeneration for immediate non-submerged implant placement using bioabsorbable materials in Beagle dogs.

The aim of the present study was to evaluate the combined application of different bioabsorbable materials for healing of residual peri-implant defects after placement of non-submerged implants into fresh extraction sockets. Second and third mandibular premolars were extracted from 10 Beagle dogs, the coronal part of the distal sockets were surgically enlarged and this was followed by immediate placement of specially designed hollow-screw non-submerged dental implants. For each animal, the coronal peri-implant defects were further treated with one of the 4 following procedures: 1) no treatment, control site; 2) grafting with porous hydroxyapatite (HA); 3) collagen membrane tightly secured around the implant and over the defect and 4) grafting with HA covered with a collagen membrane. After 16 weeks of healing, specimens were removed from the mandibule and prepared for a histomorphometric evaluation. The bone-to-implant contact length (BIC) was measured and compared amongst the different treatment modalities. In the defect area, the irregular bone regeneration was similar between all the treatment procedures (P > 0.10). In the sites covered with a collagen membrane alone, the total BIC (47%) was greater than in control sites (28.7%, P < 0.05) or sites grafted with HA (22.2%, P < 0.02). Total BIC in sites treated with the HA-membrane combination (43%) was only significantly different from sites treated with HA (P < 0.05). It is concluded that the use of bioabsorbable materials results in a limited increase of osseointegration when used in conjunction with immediate placement of non-submerged implants, although the principle of the one stage surgical approach can be maintained.

Absorbable Implants↗
PubMedDate not supplied

Histomorphometric evaluation of extraction sockets and deficient alveolar ridges treated with allograft and barrier membrane: a pilot study.

The aim of the study was to determine the fate of demineralized freeze-dried bone allograft (DFDBA) used in conjunction with a barrier membrane in the management of extraction sockets and deficient alveolar ridges, and to compare the amount of bone formed with that found in untreated sites. Ten biopsies were obtained from 8 grafted patients. Five biopsies were harvested from untreated sites during routine implant placement and analyzed for comparison. In the socket management procedure, DFDBA was packed tightly into the socket and covered with an expanded polytetrafluoroethylene (e-PTFE) membrane. Primary closure was achieved in all cases. In the ridge regeneration procedure, cortical columns were placed in the ridge projecting outward approximately 3 mm to create and maintain space for DFDBA particles packed between them; the columns were then covered by an e-PTFE membrane. Healing time ranged from 8 to 23 months. At the time of implant placement, bone cores (7 mm x 2 mm) were harvested, fixed in 10% formalin solution, and prepared for histologic examination. At the light microscopic level, no inflammation or fibrous encapsulation was observed. New bone formation on and around DFDBA particles was widespread. Histomorphometric analysis of the grafted specimens and untreated sites was carried out using the trabecular bone volume (TBV) index. The TBV in the maxillary test specimens was 55.03%, as compared to 57.33% of control cores. Unaltered DFDBA made up 8.7% of the test specimens. In the mandibular biopsies, the TBV was 56.6%, while for the controls it was 40.9%. The volume of DFDBA still present was 2.45%. The results tended to indicate that treatment with DFDBA in conjunction with cell occlusive membranes will result in new bone formation, predominantly by the process of conduction, which appears to be similar in amount and nature to that found in cores harvested from healed nonfunctional edentulous areas.

Adult↗
PubMed1992

Histomorphometric and removal torque analysis for TiO2-blasted titanium implants. An experimental study on dogs.

The aim of the present study was to compare the anchorage of TiO2-blasted screw and cylindrical implants with conventionally used machine-produced screw and cylindrical implants inserted immediately in extraction sockets on dogs. 6 adult mongrel dogs had 3rd and 4th mandibular premolars extracted bilaterally and 24 commercial pure titanium implants were placed immediately in extraction sockets and covered with mucoperiosteum. Each dog had inserted 4 implants: 1 screw implant and 1 cylindrical implant blasted with titanium-dioxide-particles; 1 screw implant and 1 cylindrical implant with machine-produced (m.p.) surface (controls). After a healing period of 12 weeks, 16 implants from 4 animals were used for removal torque test, which demonstrated that significantly higher removal torque force was needed to unscrew the implants blasted with titanium-dioxide-particles, than the normal m.p. implants. The medians for the TiO2-blasted screw and cylindrical implants were > 150 Ncm and 105 Ncm, respectively, while the values for the m.p. implants were 60 Ncm and 35 Ncm, respectively. The SEM investigation demonstrated a high irregularity of the TiO2-blasted surface compared to the machined surface. The Ra and Rz values for surface roughness were higher for the TiO2-blasted implants than for the normal m.p. implants. Histomorphometrically, the arithmetic mean of the direct bone-implant contact fraction was 69%. There was no significant difference in direct bone-implant contact length fraction between TiO2-blasted implants and the control implants. The implants blasted with titanium-dioxide-particles in this study showed a better anchorage than implants with a machine-produced surface. The screw implants showed a better anchorage than the cylindrical implants.

Animals↗
PubMed2004

Influence of implant microstructure on the dynamics of bone healing around immediate implants placed into periodontally infected sites. A confocal laser scanning microscopic study.

This study evaluated by fluorescence analysis the influence of implant microstructure on the placement of immediate implants in periodontally infected sockets. Periodontal disease was induced during 12 weeks bilaterally from P1 to P4 in six dogs. The teeth were extracted and immediate implants were placed. Each dog received six implants: three with Friadent experimental surface (grit blasted/acid etched - FES group) and three covered with titanium plasma spray (TPS group), for a total of 36 Frialit-2 stepped cylinder implants. During the healing period, fluorescent bone markers were injected to study the bone remodeling around the implants. The dyes were injected in the following sequence: oxytetracyclin hydrochloride 3 days and 8 weeks, calcein green 4 weeks after the implantation and alizarin red S 3 days before killing. The animals were anesthetized and killed 12 weeks after implant placement. The mandibles were removed, dissected and processed for analyses of the percentage of newly formed bone surrounding the implant using a confocal laser scanning microscope. There were no significant statistical differences in bone formation (Mann-Whitney) between groups (FES group: 5.28% formation at 3 days, 10.3% at 4 weeks, 21.14% at 8 weeks and 6.98% at 12 weeks; TPS group: 3.36% at 3 days, 9.58% at 4 weeks, 14.57% at 8 weeks and 7.08% at 12 weeks). However, covariance analysis showed that the percent of marked bone was statistically greater for the FES group when compared to the TPS group, between the 3-day and 8-week periods of evaluation.

Acid Etching, Dental↗
PubMed2000

Platelet-derived growth factor/insulin-like growth factor-1 combination and bone regeneration around implants placed into extraction sockets: a histometric study in dogs.

This study evaluated, by histometric analysis, the wound healing process of bone around implants placed into extraction sockets with or without the concurrent application of a combination of platelet-derived growth factor (PDGF) and insulin-like growth factor (IGF-1). Mandibular premolars were removed, and 32 implants were inserted in eight dogs. Before insertion, two implants received a single application of 5 micrograms/mL of PDGF and IGF-1 delivered in 0.10 mL of 4% methylcellulose gel or 0.10 mL of 4% methylcellulose gel only as a control. To label regenerated bone, a 2% calcein green solution was administered by intramuscular injection at 0, 7, 15, 30, 45, 60, and 75 days after implant insertion. Three, 8, and 12 weeks after implant insertion, undecalcified sections were obtained, and the degree of bone contact with the implant surface, the bone area, and the intensity of bone labeling were measured into the limits of the threads of the implant. Greater extension of bone/implant contact (paired t test, P < .05) was observed in test (22.4% +/- 13.7%) than in control (17.2% +/- 13.6%) implants at 3 weeks. One-way ANOVA revealed a higher intensity of bone labeling (P < .05) at 3 weeks than at 12 weeks (127.8 +/- 42.59 and 56.7 +/- 26.34, gray scale values) for test implants. Within the limits of the present study, it was concluded that the combination of PDGF/IGF-I actively took part in the initial phase of bone repair.

Analysis of Variance↗
PubMedDate not supplied

Four-year follow-up of larger-diameter implants placed in fresh extraction sockets using a resorbable membrane or a resorbable alloplastic material.

PURPOSE: The aim of this randomized study was to evaluate and compare the long-term success rates of cylindric, screw-type titanium implants with a larger diameter (5.9 mm) that were placed in fresh extraction sockets in association with resorbable bone substitutes or a resorbable membrane. MATERIALS AND METHODS: Eighty-three partially edentulous adult patients, selected from among those treated in 1997 and 1998 at the San Raffaele Institute in whom 1 or more implants had been placed into fresh posterior mandibular or maxillary sockets, were included in the study. A total of 111 implants were placed, 36 in mandibles and 75 in maxillae. Fifty-six implants were placed in combination with resorbable hydroxyapatite (HA group) and 55 with a resorbable membrane (MR group). Intraoral radiographs and follow-up examinations, including verification of implant stability via the Periotest, were carried out at second-stage surgery 3, 6, 9, and 12 months later; and then annually up to 4 years after placement of the definitive restoration. The radiographic examination was conducted by means of a standardized procedure to verify osseointegration. RESULTS: There was 100% attendance at the follow-up examination after 4 years. At second-stage surgery, which was performed after 4 to 6 months' healing time, none of the implants showed any signs of mobility, peri-implantitis, or bone loss. Two implants failed in the MR group, one at 3 months and one at 9 months after placement; 1 implant failed in the HA group at 4 months after placement. After 4 years, the implant success rate was 97.3% (108 of 111 implants were considered successful). The success rate did not differ significantly between the HA group (98.2%) and the MR group (96.4%). DISCUSSION: The use of larger-diameter implants served to minimize the anatomic discrepancies that would have evolved when substituting a molar with a standard-diameter implant. According to the accepted criteria for success, the 5-year success rate should be at least 85%; therefore both methods may be considered satisfactory. CONCLUSION: Implants placed in combination with a resorbable allogeneic material or with a resorbable membrane provided predictable long-term results when restored with a fixed partial denture.

Absorbable Implants↗
PubMed2001

Phenotypic comparison of periodontal ligament cells in vivo and in vitro.

The mammalian periodontal ligament contains heterogeneous populations of connective tissue cells, the precise function of which is poorly understood. Despite close proximity to bone and the application of high amplitude physical forces, cells in the periodontal ligament (PL) are capable of expressing regulatory factors that maintain PL width during adult life. The study of PL homeostasis and PL cell differentiation requires culture and phenotypic methods for precise characterization of PL cell populations, in particular those cells with an inherently osteogenic program. Currently it is unknown if cells cultured from the PL are phenotypically similar to the parental cells that are present in the tissues. We have compared the phenotype of cells in vivo with cells derived from the PL and expanded in vitro to assess the general validity of in vitro models for the study of phenotypic regulation in vivo. Rat PL cells were isolated by either scraping the root of the extracted first mandibular molars (Group A), or by scraping the alveolar socket following extraction of first mandibular molars (Group B), or by obtaining a mixture of cells after disaggregating a block of tissue consisting of first mandibular molar, PL and the surrounding alveolar bone (Group C). Cultured cells at confluence were fixed and immunostained for alpha-smooth muscle actin (alpha-SMA), osteopontin (OPN), alkaline phosphatase (AP), or bone sialoprotein (BSP). For in vivo assessments, frontal sections of rat first mandibular molar were immunostained for alpha-SMA, OPN, AP and BSP. We examined osteogenic differentiation of cultured PL cell cultures by bone nodule-forming assays. In vivo and at all examined sites, > 68% of PL cells were immunostained for AP; approximately 50% and approximately 51% for OPN and alpha-SMA (p = 0.3), respectively, while only approximately 8% were positively stained for BSP (p < 0.01). Analysis of cultured PL cells in Groups A, B and C showed 54%, 53%, and 56% positive staining for alpha-SMA respectively; 51%, 56%, 54% for OPN; 66%, 70%, 69% for AP and 2.2%, 1.4% and 2.8% for BSP. The mean percentage of PL cells in situ stained for the different markers was similar to that of cultured PL cells (Group A approximately Group B approximately Group C in situ for p > 0.2) except for BSP which was 3 to 4 fold higher in vitro (p < 0.01). PL cell cultures treated with dexamethasone showed mineralized tissue formation for all groups (A, B, C), but no mineralized tissue formation was detected in the absence of dexamethasone. As PL cells express quantitatively similar phenotypes in vitro and in vivo, we conclude that the in vitro models used here for assessment of PL cell differentiation appear to be appropriate and are independent of the cell sampling method. Further, dexamethasone-dependent progenitors are present both on the root and bone-related sides of the PL.

Actins↗
PubMed2003

Effect of recombinant human bone morphogenetic protein-2 in dehiscence defects with non-submerged immediate implants: an experimental study in Cynomolgus monkeys.

BACKGROUND: Alveolar ridge aberrations commonly compromise optimal dental implant installation. To offset any variance between an aberrant alveolar ridge and prosthetic designs, bone augmentation procedures become necessary. The objective of this study was to evaluate bone formation and osseointegration at alveolar dehiscence defects following augmentation of the defect site with recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge carrier (ACS) at dental implant installation including transmucosal positioning of the dental implant. METHODS: Four adult male Cynomolgus monkeys received dental implants in contralateral extraction socket sites with surgically created 6 x 4 mm buccal dehiscence defects following elevation of mucoperiosteal flaps. Contralateral sites received rhBMP-2/ACS (rhBMP-2 at 1.5 mg/ml; 0.1 mg/defect) or served as sham-surgery controls. The flaps were adapted and sutured around the healing abutments leaving the implants in a transmucosal position. The animals were sacrificed at 16 weeks postsurgery and block sections of the implant sites were harvested and prepared for histometric analysis. RESULTS: One dental implant from each treatment group failed to osseointegrate. Another 3 dental implants (sham-surgery controls) failed to osseointegrate with newly-formed bone in the defect area. Thus, 7 of 8 defect sites (4/4 animals) receiving rhBMP-2/ACS compared to 4 of 8 sites (2/4 animals) receiving sham-surgery exhibited evidence of osseointegration with newly formed bone in the defect area. Mean +/- SD defect height amounted to 5.3 +/- 0.2 and 5.4 +/- 0.1 mm for the rhBMP-2/ACS and sham-surgery sites, respectively. Vertical bone gain in rhBMP-2/ACS treated defects (3.9 +/- 0.3 mm) did not differ significantly from that in the sham-surgery control (3.7 +/- 0.4 mm; P > 0.05; paired t-test, N = 4). There were also no significant differences noted for coronal bone-implant contact (3.0 +/- 0.6 versus 3.6 +/- 0.5 mm), and bone-implant contact within the defect site (28.5% +/- 15.1% versus 27.4% +/- 31.7%) and within resident bone (46.9% +/- 26.8% versus 47.8% +/- 39.4%) for the rhBMP-2/ACS and control sites, respectively. CONCLUSIONS: The observations in this study point to a substantial native osteogenic potential of the alveolar process that has previously not been explored and show that surgical reentry observations of new bone formation may not necessarily indicate that osseointegration has occurred. Bone formation in control defects was substantially greater than predicted, limiting the value of adding an osteoinductive biologic construct.

Absorbable Implants↗
PubMedDate not supplied

Dental implants placed in extraction sites implanted with bioactive glass: human histology and clinical outcome.

PURPOSE: To evaluate the clinical outcome of implants placed into sites grafted with bioactive glass. MATERIALS AND METHODS: Seventeen consecutively treated patients were referred to a private specialist surgical practice for the repair of dentoalveolar defects, and/or ridge maintenance at the site of extraction sockets, prior to implantation. Bioactive glass available in 1 of 2 forms was utilized as an alloplastic grafting material. Bone cores were trephined out at the time of implantation and processed and examined to evaluate the tissue response under the light microscope. Implant mobility, marginal bone levels, and soft tissue health were all evaluated over a 2- to 3-year follow-up period to determine treatment success. RESULTS: A total of 40 Astra Tech dental implants were placed. The overall success rate at the end of the study was 88.6% for implants that were in function for a mean period of 29.2 months (22 to 24 months). One patient with 5 successful implants died at 18 months after functional loading. At that time the cumulative success rate was 90%. Another patient who was diagnosed with cancer of the large bowel lost 3 implants. If this patient were excluded from the data, the cumulative success rate increases to 96.8%. Mean marginal bone loss measured 0.5 mm mesially and 0.4 mm distally over a maximum follow-up of 36 months. Human histology demonstrated that connective tissue was seen to exist without any inflammatory response, for up to 6 months. Increasing evidence of bone formation was seen in direct relation to the bioactive glass material beyond this time frame. DISCUSSION: The need to repair and augment dentoalveolar defects necessitates the use of autogenous bone or a substitute that may be seen to avoid the additional morbidity of a donor site procedure and without risk of cross infection. The use of bioactive glass has been proposed as a viable bone substitute. The current study draws attention to the long healing time required to achieve even a small amount of new bone incorporation into the graft, as seen histologically. However, the high rate of osseointegration and continued medium-term function of implants placed into these grafted sites would indicate that the use of bioactive glass does not prohibit osseointegration. However, it is likely that the initial integration will have derived from those areas in contact with native bone. CONCLUSION: Implants will survive for up to 3 years in sites grafted with bioactive glass, even when such grafts appear to only slowly conduct new bone growth.

Adult↗
PubMed1998

The effects of guided bone regeneration and grafting on implants placed into immediate extraction sockets. An experimental study in dogs.

Guided bone regeneration (gbr) for the treatment of insufficient bone volume around implants can be performed using membranes with or without grafting materials (i.e., autogenous, allogenous, xenogenous, or alloplastic grafts). A possible way to evaluate the quality of implant osseointegration is the torque necessary to remove implants from their bony housing. The aim of this study was to compare the torques necessary to remove dental implants from implant beds reconstructed with different bone substitutes and GBR or GBR alone in 6 adult mongrel dogs. All mandibular premolars were extracted and 3 extraction sockets on each side were enlarged using a trephine bur. A 13 mm titanium screw-type dental implant (3.75 mm diameter) was placed in each enlarged extraction socket so that only the apical 3 to 4 mm were engaged in bone. The 3 defects were then randomly treated with either 1) canine demineralized freeze-dried bone allograft (DFDBA) plus GBR using an expanded polytetrafluoroethylene membrane (DFDBA+GTAM); 2) bioabsorbable hydroxyapatite and GBR (HA+GTAM); or 3) GBR (GTAM alone). After 6 months, the torque to remove the implants was measured in 4 animals and analyzed using ANOVA. There were no statistically significant differences between the 3 groups (GTAM alone: 46.37+/-16.41 Ncm; HA+GTAM: 46.00+/-16.59 Ncm; DFDBA+ GTAM: 52.15+/-29.24 Ncm). In addition, the influence of early removal of barriers on the torque values was evaluated with the t-test. Comparing exposed versus retained membranes by treatment modality, the only statistically significant difference was found in the DFDBA+GTAM group. When the torque values of all implants with exposed and retrieved membranes were compared to all those with retained membranes a significant difference could be detected. Histologic sections were prepared from the 2 dogs not included in the removal torque testing. In the histometric analysis the GTAM alone group showed a mean mineralized bone-to-implant-contact of 27.1%, the DFDBA+GTAM group of 34.6%, and the HA+GTAM of 39.3%. The mineralized bone-to-implant-contact of the HA+GTAM group was significantly higher than that of the GTAM alone group. In addition, the mineralized bone-to-implant-contact was divided into an apical and coronal part using the apical seventh thread as the dividing landmark. In the apical region, there was no significant difference between the groups regarding mineralized bone-to-implant-contact. In the coronal part the mineralized bone-to-implant-contact of the GTAM alone group was significantly lower compared to the other 2 groups. Within the limits of this investigation, it can be concluded that the type of grafting material will not influence torque removal values, but that early membrane exposure and removal will negatively influence the torque measurements. The combination of GBR with a bone substitute increased the mineralized bone-to-implant contact.

Absorbable Implants↗
PubMed2001

Transplantation of labeled periodontal ligament cells promotes regeneration of alveolar bone.

Regeneration of damaged periodontal tissues is mediated by periodontal cells, but a major sub-population comprises highly differentiated cells that do not renew. To overcome the loss of specialized cell types caused by disease, various therapeutic approaches including cell transplants have been developed to promote cell re-population in periodontal tissues. As previous transplantation studies used unlabeled cells, that are indistinguishable from host cells, it has been difficult to assess the contributions of transplanted cells to the healing processes. To track the fate and differentiation of rat periodontal cells transplanted into periodontal wounds, we used collagen-coated fluorescent beads as a permanent endocytosed marker, or cells constitutively expressing beta-galactosidase. We assessed osteogenic cell differentiation with immunohistochemical staining for osteopontin and bone sialoprotein. Cells were transplanted into periodontal wounds created in Sprague--Dawley male rats that are null for beta-galactosidase. Defects were allowed to heal spontaneously (controls), or were closed with collagen implants mixed with beta-galactosidase-positive (Lac-Z) periodontal cells, or closed with collagen implants mixed with periodontal cells loaded with fluorescent beads. Animals were killed at 1 and 2 weeks after surgery and tissues were prepared for morphometric assessment and immunostaining for osteopontin (OPN) and bone sialoprotein (BSP). Transplanted cells were easily distinguished by fluorescent beads or by beta-galactosidase-positive expression and were distributed throughout the regenerating periodontal ligament (PL) and alveolar bone. At 1 week after wounding, animals treated with beta-galactosidase-positive cells exhibited a slightly higher percentage of labeled cells in the PL compared with the fluorescent bead-labeled cell implant group (2% vs. 1% respectively; P > 0.2). At Week 2 percentages of labeled cells were slightly increased in the regenerating PL (approximately 3% for both groups, P > 0.2). In regenerating alveolar bone at 1 week, animals that were treated with beta-galactosidase-positive cells and fluorescent bead-loaded cells exhibited approximately 30% and 25% of labeled cells respectively. At 2 weeks after wounding there was an increase in the percentage of transplanted beta-galactosidase-positive cells (approximately 39% at week 2; P < 0.05), but not of transplanted cells with fluorescent beads (approximately 25% at week 2). In sites with transplanted cells there were higher percentages of OPN positive and BSP positive cells in nascent bone and more newly formed bone than in controls (>40%; P < 0.05). Transplantation of beta-galactosidase-positive cells or cells loaded with fluorescent beads is a useful method for assessing the fate and differentiation of periodontal cells in vivo. Fluorescent beads, however, are diluted at mitosis and this method underestimates the percentage of transplanted cells. As transplanted periodontal cells in both groups promoted regeneration of alveolar bone, cell transplantation could improve the restoration of periodontium destroyed by periodontitis.

Alveolar Bone Loss↗
PubMed2002

Cytotoxicity of ingredients of various dental materials and related compounds in L2- and A549 cells.

Various ingredients of dental materials and related compounds were tested for cytotoxicity in two alveolar epithelial cell lines (L2 and A549 cells). Release of lactate dehydrogenase (LDH) from cells was measured after incubation with the test substances for time intervals up to 48 h and expressed as percentage of total LDH content of lysed cells. Furthermore, the glutathione content of cells was determined in the nonmalignant L2 cells. Additionally, cell viability was assessed by microscopic examination. The highest cytotoxicity was observed with mercury compounds (methylmercuric chloride and mercury dichloride) in the range of 5-20 micromol/l. The composite components 2-hydroxyethylmethacrylate (HEMA) and triethleneglycoldimethacrylate (TEGDMA) showed time- and concentration-dependent effects of cytotoxicity at high concentrations (about 1-5 mmol/l). A time dependence for GSH decrease was mainly found for the composite components up to 12 h of cellular exposure. L2 cells were more sensitive to both mercury and composite compounds than A549 cells. Gold compounds (sodiumaurothiomalate and gold particles < 1.5 microm) did not produce any sign of toxic reactions. A time-dependent increased toxicity in pulmonary cell lines was found for the composite components HEMA and TEGDMA, but not for mercury and gold compounds.

Animals↗
PubMed2004

Two- and three-dimensional sonographic assessment of the fetal face. 2. Analysis of cleft lip, alveolus and palate.

OBJECTIVES: To describe the sonographic appearance of cleft lip with or without cleft palate (CL +/- P) using two-dimensional and three-dimensional (3D) ultrasound imaging. Also, to evaluate the accuracy of ultrasound to delineate with precision the bony extent of facial clefts, i.e. to differentiate clefts limited to the lips, or extending to the alveolus/premaxilla or the secondary palate. METHODS: This was a retrospective study based on the examination of fetuses diagnosed with an isolated CL +/- P. Cases included were either discovered at systematic screening or referred for further investigation. Clefts were characterized by their precise anatomical location and extent. The defect could include a cleft lip (CL), a cleft alveolus (CA), or a cleft of the secondary palate (CSP). RESULTS: We analyzed 96 cases of CL +/- P. The mean gestational age at examination was 28.2 +/- 4.1 weeks. The sonographic appearance of CL, CA, and CSP was depicted. Strict concordance of the sonographic report with the anatomical defect was present in 84 cases (87.5%). In eight cases, the severity of the cleft was underestimated: three cases of CA, four of CA + CSP and one of CSP were missed. In four cases, the cleft was overestimated as CA was incorrectly suspected. CONCLUSIONS: Systematic screening with sonography to detect prenatally CL +/- P requires the imaging of at least the mid-sagittal and the anterior coronal 'nose-mouth' views. Once the presence of a facial cleft is suspected, the three reference orthogonal planes are imaged in order to characterize the anatomical defect, and for each plane, the serial scans are thoroughly examined. This protocol allows precise delineation of the defect. Inclusion of 3D and 4D ultrasound imaging in the examination protocol allows easier and more rapid screening and more precise evaluation of the different cleft constituents.

Cleft Lip↗
PubMed2004

Vertical changes in patients with complete unilateral and bilateral cleft lip, alveolus and palate.

AIMS AND METHODS: Twelve UCLP and eleven BCLP patients who had been treated according to the Hanover treatment protocol were evaluated by means of cephalometric analysis and cast measurements. The aim of this investigation was to demonstrate changes in the vertical plane and in incisor position in the course of craniofacial growth compared to age-matched non-cleft controls. Lateral cephalograms and casts were analyzed for each cleft patient at age 10 and 15 and compared with corresponding data of a non-cleft control group (n = 20). RESULTS: A vertical growth impairment of the maxilla was registered in patients with cleft lip, alveolus and palate. The maxilla of the cleft patients showed a significant clockwise rotation while the inclination of the mandible remained virtually unchanged. Both upper and lower incisors, which were significantly retruded at the beginning of the late mixed dentition, could be protruded in the course of craniofacial growth, development of the dentition and treatment, but remained retruded in comparison with the non-cleft controls. The posterior midfacial height was highly significantly shorter in both UCLP and BCLP patients at both evaluation timepoints, whereas the anterior lower jaw height was greater than in the control group

Adaptation, Physiological↗
PubMed2005

Expression of mRNAs encoding for growth factors, ECM molecules, and MMP13 in mono-cultures and co-cultures of human periodontal ligament fibroblasts and alveolar bone cells.

Although the function and effects of many growth factors and extracellular matrix (ECM) molecules have been described for several periodontal tissues in vivo and in vitro, the molecular interactions involved in the communication between cells of the periodontal ligament and the alveolar bone are poorly understood. To contribute to the identification of such interactions, we have generated co-cultures (CCs) of periodontal ligament fibroblasts (PDLs) and alveolar bone cells (ABCs) and compared mRNA expression for various growth factors, ECM molecules, and matrix metalloproteinase13 (MMP13) after 1 and 2 weeks with matched mono-cultures (MCs) by reverse transcription/polymerase chain reaction. Compared with CCs of 1 week, PDLs and ABCs after 2 weeks revealed relatively high levels of all analyzed mRNAs, viz., for EGF, HGF, VEGF, TGFbeta1, collagen-I (COL1), osteonectin (ON), fibronectin (FN1), and MMP13. At week 2, when compared with MCs, CCs showed an elevation of all tested mRNAs in PDLs and ABCs, except for TGFbeta1 and FN1, which only increased in PDLs. After 1 week, when CCs were compared with MCs, mRNAs for HGF and TGFbeta1 were less abundant in PDLs and ABCs, whereas the other genes exhibited lower expression levels in only one of the cell types. Analysis of our data indicated that the expression of mRNAs for growth factors and for COL1, ON, FN1, and MMP13 was modulated in the distinct cell types with respect to culture time and culture type. The differences in the mRNA expression patterns between CCs and MCs suggest that the respective genes are involved in the molecular interactions of PDLs and ABCs.

Adolescent↗
PubMed2001

Retroviral transduction of alveolar bone cells with a temperature-sensitive SV40 large T antigen.

We have transduced adult human alveolar bone (AB) cells with a gene construct encoding a temperature-sensitive mutation of the SV40 large T antigen (tsT). Such cells divided rapidly, for more than 50 passages thus far, at a permissive low temperature (34.5 degrees C), comparable to the non-transduced parental cells at 37 degrees C. However, the tsT-transduced AB cells failed to grow at a non-permissive high temperature (39 degrees C) at which the T antigen is inactivated. Nevertheless, the cells formed mineralised nodules in vitro at both the low and high temperatures. Flow cytometry analysis showed that the transduced cells cultured at 34.5 degrees C, like the parental cells at 37 degrees C, were smaller and less granular than the transduced cells incubated at 39 degrees C. Moreover, the transduced cells grown at 34.5 degrees C were also found to express bone sialoprotein, osteopontin and type I collagen at levels similar to those of the parental cells at 37 degrees C, although osteonectin and fibronectin were down-regulated. When the transduced cells were incubated at 39 degrees C, the expression of all antigens was up-regulated, particularly osteonectin. Thus, we have obtained long-term cultures of tsT-transduced AB cells whose growth is temperature-dependent and which express certain features characteristic of bone-derived cells.

Antigens, Polyomavirus Transforming↗