Biomedical subjects

Jaime L Lozada

Publications and source records attributed to Jaime L Lozada.

7 recordsLinked to original sources

PubMed2005

Bone formation in the maxillary sinus by using platelet-rich plasma: an experimental study in sheep.

Recently, platelet-rich plasma (PRP) has been proven to be an effective regeneration adjunct when combined with autogenous bone in the reconstruction of mandibular defects. However, little is known about the effect of PRP when combined with a bone allograft in the maxillary sinus. The purpose of this study was to quantitatively evaluate the ability of PRP to enhance bone regeneration in the maxillary sinus of sheep when combined with demineralized freeze-dried bone allograft (DFDBA) and cortical cancellous freeze-dried bone allograft (CCFDBA). Ten sheep were selected for bilateral sinus augmentation DFDBA + CCFDBA + PRP (test) and DFDBA + CCFDBA (control). Five were sacrificed at 3 months and the other 5 at 6 months. Hematology tests were performed for platelet count, and histology slides were obtained for histomorphometric analysis taking 2 measures of interest: total area (square millimeters) and percentage of bone fill. Student t tests showed no significant difference between test and control groups for total area (P > .25) and percentage of bone fill (P > .80) at either 3 or 6 months. The control group showed no statistical difference for total area (P < .095) and percentage of bone fill (P <.60) between 3- and 6-month healing times. The test group, however, showed a significant increase in total area (P <.025) but not in percentage of bone fill (P <.40) for the 2 healing periods. When the treatments were compared for interactions within the animal model, no clear tendency was evident for the test group to perform in relation to the control group regarding total area (r = .766, P < .01). A moderate tendency existed between the percentages of bone filled (r = .824, P < .005). Platelet-rich plasma showed higher platelet count than did the whole blood (2 to 5 times). However, no correlation was found between the log ratio and the bone measures. Within the limitations of this study, PRP failed to enhance or accelerate bone regeneration in the maxillary sinus of sheep when combined with bone allograft.

Animals↗

PubMed2005

Clinical, histologic, and histomorphometric evaluation of mineralized solvent-dehydrated bone allograf (Puros) in human maxillary sinus grafts.

Demineralized freeze-dried bone allografts (DFDBA) have been successfully used alone or in composite grafts for many decades. Little research has been done on the effect of retaining the mineral content of bone allografts. This study histologically and histomorphometrically evaluated a new mineralized bone allograft material placed in human atrophic maxillary sinuses. Seven partially edentulous patients requiring sinus grafts before implant placement were selected for this study Their age range was 56 to 81 years (mean 67.7 years). Test grafts consisted of a mineralized solvent-dehydrated cancellous bone allograft, and control grafts were a composite of DFDBA and deproteinized bovine bone xenograft (1:1). Bilateral cases (n = 3) received both test and control grafts on opposite sides, and unilateral cases received either a test (n = 3) or control (n = 1) graft only. At 10 months, core biopsies were taken from each graft site, and dental implants were placed into the augmented bone. All bone grafts resulted in new bone formation and all implants osseointegrated. Test grafts resorbed and were replaced by newly formed bone significantly faster and in greater quantities than were control grafts. No complications with grafts or implants were noted. Both test and control grafts achieved excellent results. The faster bone formation observed with the test graft may be due, in part, to its smaller particle size compared with the bovine portion of the control graft. Test grafts were either replaced by new bone or displayed new bone-to-particle surface contact in higher percentages than did control grafts. No differences in osseointegration or graft stability were noted 2 years after the study.

Aged↗

PubMed2005

Extraction defect assessment, classification, and management.

Tooth extraction is a traumatic procedure initiating a complex cascade of biochemical and histologic events that inevitably lead to a reduction of alveolar bone and soft tissue. These tissue alterations often lead to an esthetic compromise of the future implant restoration. The hard- and soft-tissue architecture surrounding the extraction defect largely dictates the course of dental implant treatment. The EDS or extraction-defect sounding classification is a novel system introduced to simplify the decision-making process when planning for dental implant therapy following tooth extraction. Dental implant treatment guidelines based on the EDS classification are discussed. A review of pretreatment evaluations necessary to prepare for esthetic implant procedures is also presented.

Alveolar Bone Loss↗

PubMed2005

Bilaminar subepithelial connective tissue grafts for immediate implant placement and provisionalization in the esthetic zone.

Immediate implant placement and provisionalization has been considered as a preservative procedure when replacing failing teeth, especially in the esthetic zone. Nevertheless, an average facial gingival tissue recession of 1 mm is still common after one year of function. Furthermore, facial gingival recession of thin periodontal biotype seems to be more pronounced than that of thick biotype. Biotype conversion around both natural teeth and implants with subepithelial connective tissue graft has been advocated, and the resulting tissues appear to be more resistant to recession. A technique combining subepithelial connective tissue graft and immediate implant placement and provisionalization is devised to achieve a more stable peri-implant tissue in thin biotype situations. This article describes the surgical and prosthodontic approach of this procedure as well as its clinical rationale.

Adult↗

PubMed2004

Immediate functional load of mandibular implant overdentures: a surgical and prosthodontic rationale of 2 implant modalities.

Classic guidelines in osseointegration for root-form dental implants include a long healing period, during which functional load should be avoided. However, the long healing period might impose an intolerable situation on some patients, especially in the completely edentulous situation. Subperiosteal dental implant guidelines demonstrate that the implant upon insertion can be put into immediate function and be restored with the final prosthesis soon after surgery. Studies on immediately functional loaded implant-supported prostheses in patients who are completely edentulous have been reported, exhibiting high success rates comparable with conventionally loaded implants. This article describes the surgical and prosthodontic procedure for the immediately functional loaded mandibular implant overdentures in 2 different dentalimplant modalities, as well as its clinical rationale.

Dental Implantation, Endosseous↗

PubMed2002

Peri-implant tissue response of immediately loaded, threaded, HA-coated implants: 1-year results.

STATEMENT OF PROBLEM: Although high success rates have been reported with immediately loaded implants, the peri-implant tissue response has not been well documented. PURPOSE: This study evaluated implant success and peri-implant tissue response of immediately loaded, threaded, hydroxyapatite (HA)-coated root-form implants supporting mandibular bar overdentures with opposing conventional maxillary complete dentures in humans. MATERIAL AND METHODS: Five patients (3 men, 2 women; mean age 61 years) each received 4 HA-coated endosseous root-form implants in the interforaminal region in the mandible. The implants were rigidly splinted with a metal framework within 24 hours. The final EDS clip prosthesis was placed 1 to 2 weeks thereafter. The implants and peri-implant tissues were evaluated clinically and radiographically 0, 1, 3, 6, and 12 months after prosthesis placement. Data were analyzed with a repeated measures 1-way analysis of variance (P<.05). RESULTS: All implants were stable at the end of the observation period (mean Periotest value = -5.9 +/- 1.4). No peri-implant radiolucencies were noted, and no implants were lost. The mean marginal bone changes were -0.42 plus minus 0.34, -0.84 +/- 0.55, -1.14 +/- 0.80, and -1.16 +/- 0.89 mm at the 1-, 3-, 6-, and 12-month follow-ups, respectively (P<.001). Significant declines in the rates of marginal bone changes at each time interval were noted (P<.001). In addition, there were significant decreases in probing depth (P<.001) and plaque index (P<.001) but no significant difference in the frequency of bleeding upon probing (P=.64). CONCLUSION: Within the limitations of this study, the peri-implant tissue response of immediately loaded, HA-coated implants was favorable and comparable to that of conventional, delayed-loaded implants after 1 year.

Aged↗

PubMed2002

Factors affecting the survival of implants placed in grafted maxillary sinuses: a clinical report.

Many factors affect the survival rate of osseointegrated implants placed in grafted maxillary sinuses. This clinical report describes the retrospective evaluation of 60 patients with 228 implants placed in 84 grafted maxillary sinuses at the Loma Linda University School of Dentistry. The factors used to determine the survival rates of these implants were implant type, simultaneous/delayed implant placement, pretreatment bone height, oral hygiene, and cigarette smoking habits. Out of the total 228 implants, 205 (89.9%) remained in function after a mean follow-up period of 41.6 months (range 0 to 60 months). A higher failure rate was associated with the use of non-threaded implants, poor oral hygiene, and smoking. This information may facilitate treatment planning and enhance communication between the dentist and patient regarding the risk/benefit ratio and outcomes of implants placed in grafted maxillary sinuses.

Adult↗