Biomedical subjects

Roberto Crespi

Publications and source records attributed to Roberto Crespi.

14 recordsLinked to original sources

PubMed2006

Bacterial plaque colonization around dental implant surfaces.

PURPOSE: To examine the distribution of bacteria into the internal and external surfaces of failed implants using histologic analysis. MATERIALS AND METHODS: There were 10 failed pure titanium and 5 failed hydroxyapatite-coated titanium implants consecutively removed various years after their placement. Criteria for fixture removal were peri-implant radiolucency and clinical mobility. The mobile fixtures were retrieved with the patients under local anesthesia. Fixtures were removed maintaining the abutments with the aim to observe the bacterial infiltration at the level of abutment/implant interface and on the implant surface. RESULTS: A thin radiolucent space was always present around all the failed implants. The abutments screws were tightly secured in all clinical cases. The bacterial cells were composed of cocci and filaments, which were adherent to the implant surface with an orientation perpendicular to the long axis of the implant. All the specimens included in this study showed bacteria at the level of implant/abutment interface. CONCLUSIONS: Histologic analysis at the level of abutment/implant interface in 2-stage implants identified heavy bacterial colonization. These findings appear to support those studies showing bacteria penetration at the level of the micro-gap, which can legitimate the hypothesis that the micro-gap at the bone level could present a risk for bone loss caused by bacterial colonization.

Dental Abutments↗

PubMed2006

Clinical outcome of implants placed immediately after implant removal.

BACKGROUND: The purpose of this study was to evaluate the clinical success of implants placed immediately after the explantation of failed implants due to fracture at 12 months. METHODS: Nine immediate implants were placed in nine patients following explantation of nine fractured implants. Five experimental implants did not require any regenerative procedures; the remaining four immediate implants were grafted with deproteinized porcine bone particles and covered with bioabsorbable membranes. All implants were restored with fixed prostheses. The follow-up period was 12 months. RESULTS: No residual bone defects were observed or probed around any implant at the second-stage surgery, and all implants were asymptomatic and stable. All the implants were successful after prosthetic rehabilitation showing no mobility, pain, suppuration, or absence of peri-implant radiolucency. The radiographic measurements showed no significant bone loss pattern at the 12-month follow-up visit. CONCLUSION: The findings of this study suggested that implants placed immediately after implant explantation due to biomechanical fracture could be performed with results that are similar to results obtained with implants placed immediately after tooth extraction.

Adult↗

PubMed2006

Er:YAG laser scaling of diseased root surfaces: a histologic study.

BACKGROUND: The aim of the present study was to observe the effects of an erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser when used to treat periodontally involved root surfaces. METHODS: Forty teeth affected by severe periodontal disease and scheduled for extraction were divided into two groups: in group A (control), 20 teeth were treated by hand instrumentation, and in group B (test), 20 teeth were treated by Er:YAG laser. RESULTS: In group A (teeth treated by curets), the root cementum layer was completely removed, but many deep scratches on the dentin layer were also observed. In group B, the laser-treated root surfaces, there was no cracking or carbonization, and the bacterial flora was completely eliminated, leaving a rough and uniform surface. CONCLUSION: Results of the present study showed that clinical use of an Er:YAG laser in vivo achieves plaque and calculus removal, providing a rough surface morphology.

Adult↗

PubMed2006

Effects of Er:YAG laser and ultrasonic treatment on fibroblast attachment to root surfaces: an in vitro study.

BACKGROUND: The aim of this study was to analyze the effects of erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser and ultrasonic treatment on fibroblast attachment to periodontally diseased root surfaces. METHODS: Thirty single-rooted human periodontally involved teeth were included in this study. A total of 60 specimens were obtained from all selected teeth and were randomly assigned to the following three groups: group A, untreated control group; group B, ultrasonic group; and group C, Er:YAG laser at 160 mJ/pulse at 10 Hz group. All of the specimens were incubated in petri dishes with fibroblast suspension and observed by scanning electron microscopy. RESULTS: Laser-treated specimens showed a significantly higher cell density number, with a mean+/-SD of 3,720+/-316 cells/mm2. The ultrasonically treated group showed a lower cell density number, with a mean+/-SD of 658+/-140 cells/mm2. The untreated control group showed the lowest cell density number, with a mean+/-SD of 130+/-80 cells/mm2. Differences between all groups were significant (P<0.0001). CONCLUSION: The results of the study indicate that untreated control surfaces and ultrasonically treated surfaces exhibited a significantly lower number of attached cells compared to laser-treated specimens, which showed a significantly higher cell density number.

Adult↗

PubMed2005

Central odontogenic fibroma: a case report.

OBJECTIVE: The aim of this case report was to analyze clinical and histological features of a central odontogenic fibroma followed up for 6 years after surgical excision. METHODS: A 26-year old Caucasian female was referred, reporting a painless gingival swelling in the buccal area of the maxillary right canine. There were no other symptoms and no recent history of pain. Her medical history was non-contributory. Radiographic evaluation showed the presence of a radiolucent area with well-defined margins. The lesion was surgically removed and histologically analysed. RESULTS: Histologic analysis showed a cellular fibroblastic tissue characterized by interwoven bundles of collagen densely packed and absence of odontogenic epithelium. The surgical site was monitored for 6 years after surgery with no signs of recurrence. CONCLUSION: The central odontogenic fibroma here reported displayed a prominent quantity of collagen and absence of odontogenic epithelium. The surgically removed lesion had a favourable prognosis and no recurrence for the 6 year follow-up period.

Adult↗

PubMed2005

Histologic evaluation of three methods of periodontal root surface treatment in humans.

BACKGROUND: Removing subgingival plaque and calculus is a major goal of periodontal treatment. Few attempts have been made to evaluate the use of lasers for root surface debridement in periodontal therapy. The aim of the present study was to compare, histologically, the effects of hand instrumentation, ultrasonic instrumentation, and CO2 lasers on the root surfaces of teeth treated in situ. METHODS: A total of 33 teeth scheduled for extraction due to severe periodontal disease were divided into three groups. In the first group, teeth were treated by ultrasonic bactericidal curettage (UBC) with an ultrasonic scaler; in the second group, teeth were treated by hand instrumentation; and in the third group, after hand instrumentation, roots were lased by a CO2 laser. The samples were then processed for histological examination. RESULTS: In the first and second groups, plaque and calculus were present in interradicular septa, lacunae, and surface concavities. In the third group, surfaces of specimens treated by a low-power defocused CO2 laser showed areas devoid of cementum, with completely sealed dentinal tubules, and no bacterial cell remnants. CONCLUSIONS: The CO2 laser treatment, used at low power and in the defocused mode, combined with traditional mechanical instrumentation, could improve root surface debridement of periodontally involved teeth. More extensive, long-term studies are needed to confirm this hypothesis.

Carbon Dioxide↗

PubMed2005

Er:YAG laser in defocused mode for scaling of periodontally involved root surfaces: an in vitro pilot study.

BACKGROUND: The Er:YAG laser may be used on periodontally involved teeth in combination with conventional periodontal therapy in order to improve the efficacy of root instrumentation. The aim of this study was to compare the effect of hand instrumentation on root surfaces of periodontally involved teeth with Er:YAG laser application. METHODS: Thirty freshly extracted, non-carious, single-rooted, periodontally diseased human teeth from adult humans with advanced periodontal disease were used in this study. The teeth were divided into three groups of 10 specimens each. Group A was treated with scaling and root planing (SRP) with curets only (control). In group B, the root surfaces were scaled with curets and then lased with an Er:YAG laser (wavelength 2.94 microm). A handpiece with a water spray was used in non-contact mode (defocused) at a distance of 1 cm from root surface. Laser parameters were set at energy of 100 to 200 mJ/pulse, with 10 Hz of frequency. In group C, the root surfaces were lased only with power settings 250 to 300 mJ/pulse and 10 Hz frequency. An epon-araldite plastic embedding technique was used for light microscopic investigation. RESULTS: Histologic findings showed significant differences between the test and control sites. In control sites, after hand instrumentation, the surface was smooth, without a cementum layer, and the dentin layer presented opened tubules. Defects on the dentin layer were also present along root surfaces. In the test sites (B, C) root surfaces revealed no thermal damage; no cracking or tissue carbonization were observed. The superficial layers of lased surfaces appeared smooth and melted without alterations. CONCLUSION: Based on these findings, it appears that it may be feasible to use the Er:YAG laser for root instrumentation without prior root planing if the proper parameters are followed.

Adult↗

PubMed2005

Effect of Er:YAG laser on diseased root surfaces: an in vivo study.

BACKGROUND: The aim of the present study was to observe in vivo the effects of two different power settings of an Er:YAG laser on pockets of periodontally involved root surfaces using a scanning electron microscope (SEM). METHODS: Thirty-two teeth with severe periodontal disease scheduled for extraction were divided into three groups: group A was irradiated with an energy of 140 mJ, 10 Hz; group B with 160 mJ 10 Hz; group C was used as controls. Morphological changes on the treated root surfaces were evaluated using SEM observations to assess laser-induced ultrastructural changes. RESULTS: All surfaces treated in both groups showed a homogeneous and smooth root surface morphology. The surface alterations were very similar with both energy values used. CONCLUSION: Er:YAG laser irradiation performed with two different power settings of root surfaces in vivo showed at the SEM observation a complete absence of debris and smooth root surfaces.

Dental Calculus↗

PubMed2004

Immediate implants supporting single crown restoration: a 4-year prospective study.

BACKGROUND: The placement of implants at the time of tooth extraction has several clinical advantages, such as preservation of the alveolar ridge width and height and reduction of the restorative treatment time. The aim of this study was to evaluate the cumulative success rate of dental implants placed in fresh extraction sockets with and without guided bone regeneration (GBR) used to support a single crown restoration. All of the patients were preselected as candidates for implants. METHODS: Ninety-five patients aged 20 to 68 years with 163 implants were included. All patients were partially edentulous and participated in a personally tailored recall schedule. The follow-up period was 48 months. Patients underwent a clinical and radiographic evaluation annually. RESULTS: The 4-year cumulative success rate was 97%. Five of the 163 implants failed, two during the initial healing time, which were considered early failures and three a year after prosthetic rehabilitation, which were considered late failures. No failure of prosthetic rehabilitation was observed. CONCLUSIONS: Implants placed into fresh extraction sockets with or without regenerative procedures and used to support single crown prosthesis showed a very high cumulative success rate (97%) in a 4-year prospective study. Several observations should be made: 1) all the patients were preselected as candidates for implants and were following a strict oral hygiene regimen; 2) all efforts were made to reduce the number of cases requiring GBR procedures; 3) all the implants had an acid etched/sandblasted implant surface; and 4) all the prosthetic restorations were single crowns.

Adult↗

PubMedDate not supplied

Cementum formation around a titanium implant: a case report.

Animal studies have shown that a periodontal ligament may be produced around a titanium implant when it is in contact with fractured and retained roots. Formation of cementum and attachment connective tissue around titanium implants confirms that cementum progenitor cells are located in the periodontal ligament, since cementum and periodontal ligament are present at the implant-root interface, whereas the remainder of the implant, which is not in contact with the root, shows osseointegration. The aim was to evaluate histologically the characteristics of the tissue present between a titanium implant and a retained root, which were subsequently extracted as a result of peri-implantitis. The histologic examination revealed a continuous layer of cementum and numerous cementocytes on the implant surface. No blood vessel or collagen fibers were detected in the periodontal space. In contrast to experimental studies carried out on animals, the lack of connective tissue fibers and the presence of hypercementosis in this specimen could have been caused by the inflammatory process. Furthermore, the extrusive movement of the root might explain the presence of cementum hypertrophy. Further studies are required to establish whether the neoformation of cementum and collagen fibers on an implant in the presence of root residues occurs only in animal models or whether it may also occur in humans.

Adult↗

PubMedDate not supplied

Soft tissue healing around implants placed immediately after tooth extraction without incision: a clinical report.

PURPOSE: The purposes of the present study were to evaluate implants placed immediately after tooth extraction without incision or primary flap closure and to observe the peri-implant soft tissue healing. MATERIALS AND METHODS: Fifteen patients (9 men and 6 women) aged 31 to 54 years were included in this study. Each patient had a tooth that required extraction, and each had at least 4 mm of bone beyond the root apex. Teeth with multiple roots were excluded from this study. After tooth extraction, the implants were immediately placed without incision or flap elevation. Implant sites showing bone fenestrations, bone dehiscences, or peri-implant bone defects exceeding 2 mm were excluded from this study. In these cases, a standard guided bone regeneration procedure with a surgical flap elevation was used. The second-stage surgical procedure was performed 6 months after the first procedure. The following clinical parameters were evaluated at the time of implant placement and at second-stage surgery: levels of mesial and distal papillae, width of keratinized mucosa, position of mucogingival junction relating to the surrounding tissues, and peri-implant radiolucency and marginal bone loss, which were evaluated radiographically. RESULTS: The postsurgical healing period was uneventful for all patients. Soft tissue closure over the implant sites was achieved in 1 to 3 weeks after surgery at all sites. At second-stage surgery, no peri-implant bone defects were observed or detected by probing around all the experimental implants. The soft tissue anatomy was considered clinically acceptable in all patients. DISCUSSION AND CONCLUSION: Successful osseointegration and complete bone healing were observed for all patients. The soft tissue healing and morphology were satisfactory; additional mucogingival surgery was not required before definitive prosthetic rehabilitation.

Adult↗

PubMedDate not supplied

Maxillary sinus augmentation: histologic and histomorphometric analysis.

PURPOSE: Implant placement in the posterior maxilla may often be contraindicated because of insufficient bone volume and the presence of the maxillary sinus. In these situations, sinus floor lifting and grafting frequently have been proposed as the best treatment. The aim of this study was to compare histologically the use of 100% autogenous bone versus a combination of autogenous bone and corticocancellous pig bone for maxillary sinus augmentation. MATERIALS AND METHODS: Eighteen patients requiring bilateral maxillary sinus augmentation were selected for this study. Bone for grafting was harvested from the iliac crest. Each patient received 100% autogenous bone in 1 randomly selected sinus (control side) and a 1:1 mixture of autogenous bone and corticocancellous pig bone particles in the contralateral sinus (test side). Five months after the augmentation procedure, bone biopsy specimens were taken at the time of implant placement. RESULTS: No complications were observed during the surgical procedures; all patients healed uneventfully. No signs or symptoms of maxillary sinus disease were observed during the 5 months after surgery. No significant differences in bone percentages were observed in the bone biopsies from test and control sides. DISCUSSION AND CONCLUSION: It could be concluded from this study that corticocancellous pig bone particles can be successfully used in a 1:1 mixture with autogenous bone from the iliac crest for maxillary sinus augmentation in cases of severely atrophic maxilla.

Adult↗

PubMedDate not supplied

A clinical study of the outcomes and complications associated with maxillary sinus augmentation.

PURPOSE: The aim of this study was to evaluate the rate of complications in maxillary sinus augmentation surgery and the impact of complications on subsequent implant treatment in a patient population with severe maxillary atrophy scheduled for treatment under general anesthesia. MATERIALS AND METHODS: The study population consisted of 70 patients (124 sinuses) with severe maxillary atrophy who underwent maxillary sinus augmentation. Sixteen patients were scheduled to have a unilateral procedure and 54 patients a bilateral procedure. Sinus augmentation was performed with autogenous bone alone in 93 sinuses; in 31 sinuses, a 1:1 mixture of autogenous bone and corticocancellous pig bone particles was used. Twenty-six of 124 procedures involved both sinus augmentation and autogenous block grafting for the treatment of severely atrophic maxillae. RESULTS: The most common intraoperative complication was the perforation of the sinus membrane, which was observed in 31 sinuses (25%). Seven (5.6%) sinuses in 7 patients exhibited suppuration of the maxillary sinus. Five of the 7 patients with sinus infection were smokers, showing a prevalence of complications significantly greater in smokers compared to nonsmokers. Moreover, the use of an onlay bone graft in conjunction with sinus augmentation appeared to significantly increase the rate of infective complications. Infections were treated by drainage and the administration of systemic antibiotics. Two clinical cases showing persistent signs of infection required an endoscopic inspection of the maxillary sinus. DISCUSSION AND CONCLUSION: In the present study sinus membrane perforation was not shown to be a significant factor in the rate of implant complications. However, the combination of smoking and onlay bone grafting could significantly increase the rate of postoperative infection following sinus grafting.

Adult↗

PubMedDate not supplied

Osteoblast attachment on titanium disks after laser irradiation.

PURPOSE: Osteoblast attachment on titanium surfaces is necessary to achieve new bone formation and osseointegration. The purpose of this study was to examine osteoblast attachment on irradiated titanium disks. MATERIALS AND METHODS: Machined, hydroxyapatite (HA)-coated, sandblasted, and titanium plasma-sprayed (TPS) surfaces were irradiated with either a carbon dioxide (CO2) or an Er,Cr:YSGG laser. A control group of nonirradiated disks was also examined. Osteoblast cultures were cultivated on the titanium disks and examined with scanning electron microscopy. RESULTS: The findings demonstrated that osteoblasts could be grown on all of the surfaces. Pseudopodia and a spread of cells that demonstrated maturation were observed on the lased irradiated titanium disks. CONCLUSIONS: The data show that laser irradiation of titanium surfaces may promote osteoblast attachment and further bone formation.

Cell Adhesion↗