RESUMEN
OBJECTIVES: To identify risk factors for early failure of immediately placed implants in molar regions associated with three bone regenerative techniques. METHODS: Ninety-two patients (44 women and 48 men; mean age 50 years, 35 smokers and 57 non-smokers) in need of a single implant crown to replace a molar were included. After placing the implant, patients were randomized to one of three treatment groups for bone reconstruction of remaining periimplant defects: Autologous bone (AB) chips, Ossix membrane (OM) or a combination of AB chips and OM. The implant was submerged, and after 4 months of healing a re-entry surgery was made to connect a healing abutment. Implants with a dehiscence on ≥2 sites (mesial/distal/oral/buccal) together with ≥50% visible threads, were judged as failures. A series of simple logistic regression analyses were performed to identify risk factors for failure among the following independent variables: sex, jaw, smoking status, plaque, bleeding on probing, fistula, extraction reason, mean initial periimplant defect size, treatment group, implant length, buccal bone dehiscence (BBD), soft-tissue dehiscence and infection. The identified risk factors entered a multiple logistic regression analysis. RESULTS: Fifteen implants failed before abutment operation (13 explantations/two non-osseointegrated). Treatment group had no impact on failure. Risk factors for failure were: Smoking >10 cigarettes/day (odds ratio [OR]=9.29, confidence interval [CI]=1.21-71.16), BBD (OR=11.43, CI=1.34-97.74) and infection (OR=36.7, CI=2.75-489.31). CONCLUSIONS: Implants placed immediately after extraction of a molar were associated with a high risk for failure at abutment operation. There was no difference in failure rate between three bone reconstructive techniques.
Asunto(s)
Coronas , Implantación Dental Endoósea/métodos , Implantes Dentales de Diente Único , Fracaso de la Restauración Dental , Adulto , Anciano , Análisis de Varianza , Trasplante Óseo/métodos , Colágeno , Pilares Dentales , Femenino , Humanos , Carga Inmediata del Implante Dental , Modelos Logísticos , Masculino , Persona de Mediana Edad , Diente Molar/cirugía , Periimplantitis/complicaciones , Factores de Riesgo , Fumar/efectos adversos , Dehiscencia de la Herida Operatoria/complicaciones , Trasplante AutólogoRESUMEN
OBJECTIVES: To evaluate marginal bone changes radiographically and clinically around immediately placed implants in molar regions associated with three bone regenerative techniques 12 months after loading. METHODS: Ninety-two patients received an implant after random allocation to a bone reconstruction method of remaining peri-implant bone defects using either Autologous bone (AB) chips, Ossix membrane (OM) or a combinations of AB chips and OM. After 4 months of healing, a re-entry surgery was performed to connect a healing abutment. A screw-retained crown was mounted 4-6 weeks afterwards. Seventy-six patients attended a follow-up visit 12 months after loading. Marginal bone level was assessed radiographically before re-entry surgery and at the 12-month follow-up; probing pocket depth (PPD) and probing defect depth (PDD) at the implant platform level without the mounted crown were assessed after and just before crown delivery respectively and at the 12-month follow-up. RESULTS: Fifteen implants were judged as failures at re-entry surgery, and one patient died before follow-up. A statistically significant bone loss was seen in the three groups after 12 months (average 0.48 mm), but no significant differences were found among the groups. Likewise, no differences in PPD or PDD could be found between the groups. An average bone loss of 0.48 mm was recorded at the 12-month follow-up examination resulting in an average peri-implant bone level of approximately 1.1 mm related to an average PPD of 3.1 mm and an average PDD of 1.3 mm. CONCLUSIONS: After 12 months of loading, no significant differences in peri-implant bone level were observed after the use of three bone regenerative techniques in connection with immediately placed implants in molar regions.
Asunto(s)
Implantación Dental Endoósea/métodos , Implantes Dentales de Diente Único , Mandíbula/cirugía , Diente Molar , Adulto , Anciano , Pérdida de Hueso Alveolar/diagnóstico por imagen , Colágeno , Coronas , Pilares Dentales , Diseño de Prótesis Dental , Fracaso de la Restauración Dental , Femenino , Estudios de Seguimiento , Humanos , Carga Inmediata del Implante Dental , Masculino , Mandíbula/diagnóstico por imagen , Persona de Mediana Edad , Bolsa Periodontal/clasificación , Estudios Prospectivos , Radiografía , Resultado del TratamientoRESUMEN
OBJECTIVES: To evaluate the effect of immortalized hypertrophic chondrocytes extracellular matrix (HCM) with or without the use of guided bone regeneration (GBR) on the healing of critical-size calvarial defects. MATERIAL AND METHODS: In 42 rats, 5 mm critical-size calvarial defects were surgically created. The animals were randomly allocated to six groups of seven rats each: Group A1: one defect was left untreated (control), while the contralateral defect was covered by a double non-resorbable membrane (GBR). Group B1: one defect was filled with calcium phosphate cement (CP), while the contralateral defect was treated with GBR and CP. Group C1: one defect was filled with a mixture of CP and HCM, while the contralateral defect was treated with GBR and CP+HCM. The healing period for all three groups was 30 days. The remaining three groups were treated in a similar manner but the healing period was 60 days. Five animals from each group were evaluated by maceration and two animals were analysed histologically. RESULTS: At 30 days, all the control-treated defects did not present complete closure. When GBR was applied alone or combined with CP, 3/5 and 5/5 defects, respectively, presented complete closure. At 60 days, one defect from the control group presented complete closure. All the defects treated with GBR alone presented complete closure, whereas the combined use of GBR with CP or CP+HCM resulted in 4/5 and 3/5 defects with complete closure, respectively. The only treatment modality that did not present any specimen with defect closure at both 30 and 60 days was the combination of CP+HCM. The histological analysis indicated that when GBR was not used alone, the healing consisted of an amorphous acellular structure and loose granulation tissue, which, even though clinically resembled hard tissue, did not demonstrate the histological characteristics of bone. CONCLUSION: The predictability of bone formation in critical-size defects depends mainly on the presence or absence of barrier membranes. The combined use of GBR with calcium phosphate alone or in combination with immortalized human HCM did not enhance the potential for osseous healing provided by the GBR procedure.
Asunto(s)
Trasplante Óseo/métodos , Condrocitos/trasplante , Matriz Extracelular/trasplante , Regeneración Tisular Dirigida/métodos , Cráneo/cirugía , Animales , Materiales Biocompatibles , Sustitutos de Huesos/farmacología , Fosfatos de Calcio/farmacología , Cefalometría , Humanos , Masculino , Membranas Artificiales , Politetrafluoroetileno/farmacología , Ratas , Ratas Wistar , Reproducibilidad de los Resultados , Estadísticas no ParamétricasRESUMEN
OBJECTIVES: To compare implants with a rough surface in their whole length (FR) with implants having a 2 mm coronal machined portion (PR) when used in association with a sinus-lift procedure. MATERIAL AND METHODS: Twenty-six patients with 2 mm< or =x< or =9 mm residual alveolar crest were prosthetically restored with implants after a staged sinus-lift procedure using osteotomes. In 13 randomly chosen patients, no more than one FR implant was placed (test group), while the rest were PR implants. The other 13 patients received only PR implants (control group). For comparisons, only one implant from each patient was used, i.e., from the test group only the 13 FR implants were used, while from the control group, one PR implant was randomly chosen. The presence/absence of plaque, BOP, PPD and REC were registered at the day of delivery of the restorations and after 1 year. Residual alveolar crest height and marginal bone levels around the implants were evaluated on standardized periapical radiographs taken at various stages. RESULTS: Four FR and two PR implants were lost, and the cumulative survival rate was 82.9% (six lost out of 35). There were no significant differences between the two groups. Implant type, residual alveolar crest height, time of osseointegration, time of implant loading and smoking did not seem to influence implant survival. CONCLUSIONS: FR and PR implants placed in augmented sinuses did not differ in their clinical performance.
Asunto(s)
Aumento de la Cresta Alveolar/métodos , Implantes Dentales , Diseño de Prótesis Dental , Maxilar/cirugía , Seno Maxilar/cirugía , Proceso Alveolar/patología , Trasplante Óseo/métodos , Pilares Dentales , Placa Dental/clasificación , Fracaso de la Restauración Dental , Femenino , Estudios de Seguimiento , Hemorragia Gingival/clasificación , Recesión Gingival/clasificación , Humanos , Masculino , Maxilar/patología , Persona de Mediana Edad , Oseointegración/fisiología , Osteotomía/métodos , Bolsa Periodontal/clasificación , Propiedades de Superficie , Análisis de SupervivenciaRESUMEN
To evaluate the osteoinductive potential of deproteinized bovine bone mineral (DBBM) and an enamel matrix derivative (EMD) in the muscle of rats. Sixteen rats were used in this study. The animals were divided in three groups. Group A: a pouch was created in one of the pectoralis profundis muscles of the thorax of the rats and DBBM particles (Bio-Oss) were placed into the pouch. Healing: 60 days. Group B: a small pouch was created on both pectoralis profundis muscles at each side of the thorax midline. In one side, a mixture of EMD (Emdogain) mixed with DBBM was placed into one of the pouches, whereas in the contralateral side of the thorax the pouch was implanted with DBBM mixed with the propylene glycol alginate (PGA--carrier for enamel matrix proteins of EMD). Healing: 60 days. Group C: the same procedure as group B, but with a healing period of 120 days. Qualitative histological analysis of the results was performed. At 60 days, the histological appearance of the DBBM particles implanted alone was similar to that of the particles implanted together with EMD or PGA at both 60 and 120 days. The DBBM particles were encapsulated into a connective tissue stroma and an inflammatory infiltrate. At 120 days, the DBBM particles implanted together with EMD or PGA exhibited the presence of resorption lacunae in some cases. Intramuscular bone formation was not encountered in any group. The implantation of DBBM particles alone, combined with EMD or its carrier (PGA) failed to exhibit extraskeletal, bone-inductive properties.
Asunto(s)
Sustitutos de Huesos/farmacología , Proteínas del Esmalte Dental/farmacología , Minerales/farmacología , Osteogénesis/fisiología , Animales , Bovinos , Músculos/efectos de los fármacos , Enfermedades Musculares/etiología , Osificación Heterotópica/etiología , Ratas , Ratas WistarRESUMEN
PURPOSE: The aim of this study was to evaluate interproximal papillae and clinical crown height following the placement of single-tooth implants according to early and delayed protocols. MATERIALS AND METHODS: Forty-five patients were randomly allocated to either the "early" group or the "delayed" group. They were treated with a single-tooth acid-etched Osseotite implant in the maxillary or mandibular anterior or premolar region an average of 10 days (in the case of early placement) or 3 months (in the case of delayed placement) following tooth extraction. Interproximal papilla dimensions and clinical crown height were evaluated using a score index in 39 patients who attended a follow-up visit 16 to 18 months after prosthesis delivery. The patients were evaluated in photographs taken 1 week after crown placement (baseline) and approximately 1.5 years after crown placement (follow-up). RESULTS: It was demonstrated by logistic regression the risk of presenting no papilla or a negative papilla was 7 times greater at baseline for delayed cases than for early cases (33% versus 8%). However, the soft tissue fill in the proximal spaces improved significantly from baseline to the 1.5-year follow-up in both groups, with no significant difference between the groups found at follow-up. The papilla height almost 2 years after implant placement was inversely correlated with patient age. The clinical crown height was acceptable in significantly more cases in the early group than in the delayed group at follow-up. Half of the crowns in the delayed group exhibited an inappropriate height; of these, almost two thirds were assessed to be too short. DISCUSSION AND CONCLUSION: Early placement of single-tooth implants may be preferable to delayed implant placement technique in terms of early generation of interproximal papillae and the achievement of an appropriate clinical crown height, but no difference in papilla dimensions was seen at 1.5 years after seating of the implant crown.
Asunto(s)
Implantación Dental Endoósea/métodos , Implantes Dentales de Diente Único , Prótesis Dental de Soporte Implantado , Encía/anatomía & histología , Adulto , Factores de Edad , Anciano , Distribución de Chi-Cuadrado , Coronas , Femenino , Estudios de Seguimiento , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Método Simple Ciego , Factores de Tiempo , Cicatrización de HeridasRESUMEN
OBJECTIVES: The aim of the present study was to evaluate whether the placement of implants in bone formed by means of guided tissue regeneration (GTR) beyond the skeletal envelope may influence bone volume and/or structure. MATERIAL AND METHODS: Rigid, hemispherical, Teflon capsules were placed with their open part facing the lateral surface of the ramus in both sides of the mandible in 18 rats. After 1 year, the capsules were removed by a re-entry operation, and a custom-made titanium implant was placed in the augmented ramus in only one side of the jaw. Six animals were sacrificed shortly after implant surgery, another six after 3 months, and the last six after 6 months. Histological specimens of the augmented sites including the implants were prepared, and the volumes of (1) the newly formed bone (mineralized bone and marrow) (2) the soft connective tissue, and (3) the implant, in the space originally created by the capsule were estimated by a point-counting technique. Additionally the height of the augmented bone was measured. RESULTS: One year after capsule placement, the major portion of the space originally created by the capsules was filled with newly formed bone. In the test specimens, implant placement seemed to result in a denser arrangement of the augmented bone, but this event did not influence its long-term stability. Although some resorption occurred after 3 and 6 months, the vast portion of the generated bone remained stable over time in both tests and controls, and there were no differences between tests and controls at any observation periods. CONCLUSION: It is concluded that large amounts of bone can be formed beyond the skeletal envelope by means of GTR, and that this bone remains stable on a long-term basis both with and without the placement of titanium implants.
Asunto(s)
Implantación Dental Endoósea/métodos , Regeneración Tisular Guiada Periodontal/métodos , Mandíbula/cirugía , Animales , Implantes Dentales , Ratas , Ratas WistarRESUMEN
OBJECTIVES: The aim of the present study was to compare the delayed-immediate (Im) and the delayed (De) protocols for placement of single-tooth implants. MATERIAL AND METHODS: After allocation to the Im and De groups by random, 46 patients were treated with a single-tooth implant with acid etched surfaces (Osseotite) in the anterior or pre-molar region of the maxilla or the mandible on average 10 days (Im) or 3 months (De) following tooth extraction, respectively. Forty-one patients attended a follow-up visit 2 years after implant placement corresponding to 1(1/2) years of loading of the implant restorations. Peri-implant and prosthetic parameters were evaluated clinically and marginal bone levels measured on radiographs. RESULTS: Three implants were lost, all before mounting of the crown. None of the implant restorations had failed after 1(1/2) years of function. Probing pocket depths were reduced by up to 1.4 mm on average from the time of loading to the 2-year follow-up and at that time, no significant difference between the Im and De groups was found (4.2 versus 4.1 mm). A statistically significant radiographic marginal bone loss had occurred in the Im group (mean=0.8 mm) as well as in the De group (mean=0.7 mm) in the follow-up period. However, a mean marginal bone level of approx. 1.5 mm in both groups measured from the implant-abutment junction was found to be acceptable. It was demonstrated that probing pocket depths and marginal bone levels after 1(1/2) years of loading of the implant-retained crowns were not influenced by the presence of peri-implant bone defects immediately after implant placement. Furthermore, no severe prosthodontic complications, such as screw loosening or porcelain fractures, arose in this study material. CONCLUSION: High success rates of single-tooth implants after 1(1/2) years of function were achieved using the delayed-immediate and delayed implant placement techniques.
Asunto(s)
Pérdida de Hueso Alveolar/etiología , Implantación Dental Endoósea/efectos adversos , Implantación Dental Endoósea/métodos , Implantes Dentales de Diente Único , Prótesis Dental de Soporte Implantado , Pérdida de Hueso Alveolar/diagnóstico por imagen , Coronas , Implantes Dentales de Diente Único/efectos adversos , Fracaso de la Restauración Dental , Dentadura Parcial Inmediata , Femenino , Estudios de Seguimiento , Humanos , Masculino , Pronóstico , Estudios Prospectivos , Radiografía , Estadísticas no Paramétricas , Extracción Dental/efectos adversos , Alveolo DentalRESUMEN
The aim of the study was to compare the long-term stability of membranous and endochondral autogenous bone grafts with or without combined application of guided bone regeneration (GBR). Twenty-five, male, 6-month old, albino rats were used in the study. The animals were divided into four groups (A5, A11, B5 and B11). Group A5 (control): The inferior border of the mandible was exposed in both sides. At one side of the jaw, a calvarial bone graft (baseline -3 x 4 x 0.64 mm) was placed at the inferior border of the mandible and was fixed with a standardized screw-type titanium microimplant. At the contralateral side, an ischiac bone graft (baseline -3 x 4 x 0.87) was transplanted. The healing period was 5 months. Group A11 (control): The animals were treated in the same manner as in Group A5 with the difference that the healing period was 11 months. Group B5 (test): The animals were treated in the same manner as in Group A5 with the difference that an e-PTFE membrane was adapted over the bone graft on each side of the jaw. Group B11 (test): The animals were treated in the same manner as in Group B5 with the difference that 5 months following transplantation the animals were subjected to a second operation and the membranes were removed. The healing period was 11 months. The animals were killed at 5 (Groups A5 and B5) or at 11 months (Groups A11 and B11) following mandibular augmentation and the jaws were defleshed. The width, the length and the thickness/height of the bone graft were evaluated by means of a stereomicroscope. At 5 months, both types of the membrane-treated bone grafts presented increase in all dimensions compared with baseline. However at 11 months, both types of the membrane-treated bone grafts exhibited a decrease in their dimensions which were similar to the baseline measurements. In the control groups, both types of bone graft presented significant resorption both at 5 and at 11 months with the ischiac bone grafts presenting more resorption in width and length than the calvarial bone grafts. It can be concluded that the long-term volume stability of autogenous endochondral and membranous onlay bone grafts combined with GBR is superior to that of autogenous endochondral and membranous onlay bone grafts alone.
Asunto(s)
Regeneración Ósea , Trasplante Óseo/métodos , Regeneración Tisular Guiada Periodontal/métodos , Animales , Materiales Biocompatibles/uso terapéutico , Isquion/trasplante , Masculino , Mandíbula/cirugía , Ratas , Cráneo/trasplante , Factores de Tiempo , Trasplante AutólogoRESUMEN
The aim of this study was to evaluate whether the use of enamel matrix proteins with or without the use of deproteinized bovine bone influences bone formation when used as an adjunct to guided bone regeneration (GBR). Twenty rats, divided into four groups of five animals each, were used in this study. Group A1: A hemispherical PTFE capsule was placed empty on the lateral aspect of the mandibular ramus (GBR). At the contralateral side of the jaw, the capsule was filled with an enamel matrix derivative (EMD) before its placement. The healing period was 60 days. Group A2: The animals were treated in the same manner as in Group A1 but with a healing period of 120 days. Group B1: The animals were treated in the same manner as in Group A1 with the difference that deproteinized bovine bone mineral (DBBM) particles were packed in the capsule. At the contralateral side of the jaw, the capsule was filled with a mixture of EMD and DBBM. The healing period was 60 days. Group B2: The same treatment as in B1 but with a healing period of 120 days. The histological analysis revealed that in Groups A1 and A2 newly formed bone was covering a significant part of the empty capsules (GBR). The use of EMD in the capsule did not offer any added benefit to the use of the capsule alone in terms of new bone formation. At Groups B1 and B2, the presence of DBBM and/or EMD did not positively affect the amount of new bone formation. It can be suggested that neither the application of EMD nor the use of DBBM or the combination of EMD and DBBM results in enhanced amounts of bone formation in comparison with the GBR procedure alone.
Asunto(s)
Regeneración Ósea , Sustitutos de Huesos/uso terapéutico , Trasplante Óseo/métodos , Proteínas del Esmalte Dental/uso terapéutico , Regeneración Tisular Guiada Periodontal/métodos , Animales , Matriz Ósea/trasplante , Bovinos , Masculino , Mandíbula/cirugía , Ratas , Trasplante Heterólogo/métodosRESUMEN
OBJECTIVES: Recent investigations have focused on patients' subjective assessment of implant treatment. The aim of this study was to compare the patients' experience of surgical and prosthetic procedures, as well as satisfaction with function and aesthetics following single-tooth replacements mounted to early vs. delayed placed dental implants. MATERIAL AND METHODS: Forty-six patients were treated with a single-tooth implant in the anterior or premolar region. Twenty-three implants were placed on average 10 days after tooth extraction (Im), while 23 implants were placed approximately 3 months after tooth extraction (De). Forty-one patients completed a questionnaire regarding the treatment using visual analog scales (VAS) and check boxes 16-18 months after delivery of the restoration. RESULTS: In all, 90% of the respondents rated 88 or higher on the VAS regarding satisfaction with the crown. Satisfaction with the restoration in general and the appearance was significantly greater in the Im group than in the De group (96 vs. 93; P<0.02). Assessment of the implant surgery was not significantly different between the delayed-immediate and the delayed group. Approximately 25% of the patients experienced unpleasantness in relation to the prosthetic procedures, and in 8 of 11 cases, impression taking was the cause. When evaluating satisfaction with the overall implant treatment, the VAS scores for the delayed-immediate group were significantly higher than for the delayed group (96 vs. 90; P<0.02). CONCLUSION: The patients in the present study were highly satisfied with the outcome of the treatment and experienced it to be without significant unpleasantness irrespective of the treatment concept.
Asunto(s)
Implantación Dental Endoósea/métodos , Implantación Dental Endoósea/psicología , Implantes Dentales de Diente Único/psicología , Satisfacción del Paciente , Adulto , Factores de Edad , Anciano , Distribución de Chi-Cuadrado , Coronas , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores Sexuales , Estadísticas no Paramétricas , Encuestas y Cuestionarios , Factores de Tiempo , Extracción Dental , Alveolo DentalRESUMEN
AIM: This study aimed to compare the susceptibility of guided tissue regeneration (GTR)-regenerated periodontal attachment to ligature-induced periodontitis with that of the pristine periodontium. METHODS: Periodontal breakdown was produced in four monkeys by the placement of orthodontic elastics around experimental teeth (test teeth). During a flap operation, the root surfaces were scaled and planed, and a notch indicating the apical termination of scaling and root planing was made in the root surface. Following resection of the crowns and endodontic treatment, an e-PTFE membrane was adapted over the roots. Subsequently, the flaps were sutured to complete closure of the wound (submerged). At membrane removal after 5 weeks, the crowns of the contralateral teeth serving as controls were resected, and the roots treated endodontically during a flap operation. Artificial composite crowns were then placed on both test and control roots. After 3 months of tooth cleaning, cotton floss ligatures were placed passively around both test and control teeth for a period of 6 months. Two weeks later the animals were sacrificed. RESULTS: Histological analysis demonstrated that the instrumented root surfaces of the test teeth were covered by newly formed cementum of the reparative, cellular, extrinsic and intrinsic fiber type, while the cementum on the controls was mainly acellular extrinsic fiber cementum. Histometric assessments demonstrated that similar attachment loss had occurred on test (1.0+/-0.5 mm) and control roots (1.0+/-0.4 mm) during the 6 months of ligature-induced plaque accumulation. CONCLUSION: The results indicate that teeth with a periodontal attachment apparatus formed by GTR is not more susceptible to periodontitis than those with a pristine periodontium.
Asunto(s)
Regeneración Tisular Guiada Periodontal , Ligamento Periodontal/fisiopatología , Periodontitis/fisiopatología , Animales , Cemento Dental/patología , Cemento Dental/fisiopatología , Placa Dental/fisiopatología , Raspado Dental , Susceptibilidad a Enfermedades , Ligadura/instrumentación , Macaca fascicularis , Membranas Artificiales , Higiene Bucal , Pérdida de la Inserción Periodontal/patología , Pérdida de la Inserción Periodontal/fisiopatología , Ligamento Periodontal/cirugía , Bolsa Periodontal/patología , Bolsa Periodontal/fisiopatología , Periodontitis/cirugía , Politetrafluoroetileno , Aplanamiento de la Raíz , Estadísticas no Paramétricas , Colgajos QuirúrgicosRESUMEN
OBJECTIVES: The aim of the study was to examine whether bone produced by guided tissue regeneration (GTR) in combination with Bio-Oss or Biogran is stable on a long-term basis. MATERIAL AND METHODS: Fifty-four, 3-month-old Wistar rats were divided into three groups and rigid, hemispherical, teflon capsules were placed with their open part facing the lateral surface of the exposed mandibular ramus (one capsule per animal). In the first group, the capsules were loosely packed with a standardized quantity of Bio-Oss, in the second group with Biogran, and in the last group were left empty. After 1 year of healing, the capsules were removed. Six animals from each of the 3 experimental groups were killed immediately after capsule removal (baseline), or 3 or 6 months after re-entry. The volume of (1) newly formed bone, (2) remaining biomaterial particles, and (3) soft connective tissue in the space originally created by the capsule was estimated by a point-counting technique in three to four histological sections, taken by uniformly random sampling. RESULTS: While considerable bone formation had occurred in the empty control capsules, only limited bone formation was observed in the two test groups. The major portion of the space originally created by the capsules in the test groups was occupied by biomaterial particles embedded in connective tissue. At baseline, the mean volume of newly formed bone occupied 23% of the original capsule space in the animals grafted with Bio-Oss, 12.6% in those implanted with Biogran, and 94.1% in those that received empty control capsules. Six months after capsule removal, the corresponding values were 21.5%, 13.2%, and 91.7%, respectively. No statistically significant differences were observed between baseline, and the 3-, and 6-month observation times in terms of bone volume for any of the three treatment groups (p>0.05). CONCLUSION: Bone produced by GTR with and without implantation of Bio-Oss, or Biogran, is stable on a long-term basis, but bone formation is obstructed by implantation of these biomaterials.
Asunto(s)
Materiales Biocompatibles/uso terapéutico , Matriz Ósea/trasplante , Sustitutos de Huesos/uso terapéutico , Huesos/patología , Vidrio , Regeneración Tisular Dirigida , Minerales/uso terapéutico , Animales , Médula Ósea/patología , Remodelación Ósea/fisiología , Huesos/fisiopatología , Tejido Conectivo/patología , Mandíbula/patología , Mandíbula/cirugía , Osteocitos/patología , Osteogénesis/fisiología , Ratas , Ratas Wistar , Factores de Tiempo , Cicatrización de HeridasRESUMEN
OBJECTIVES: To evaluate the effect of guided bone regeneration (GBR) in combination with or without deproteinized bovine bone mineral (DBBM) and/or an enamel matrix derivative (EMD) on the healing of critical-size calvarial defects. MATERIAL AND METHODS: Forty rats were used. In all animals, a standardized critical-size calvarial defect was created surgically. The animals were randomly allocated into 4 groups of 10 animals each. Group A: One calvarial defect was left untreated, while the galeal and the cerebral aspect of the contralateral defect were covered with a bioresorbable membrane (GBR). Group B: One calvarial defect was filled with EMD, while the contralateral defect was treated with GBR and EMD. Group C: One defect was filled with DBBM, while the contralateral defect was treated with combination of GBR and DBBM. Group D: One defect was filled with DBBM combined with EMD, while the contralateral defect was treated with combination of GBR, DBBM and EMD. The healing period was 4 months. Five specimens from each group were macerated and the length, the width and the vertical dimension (thickness) of the remaining defect were evaluated by a stereomicroscope. The remaining specimens in each group were analyzed histologically. RESULTS: The defects of the macerated specimens that were left untreated or were treated only by EMD, DBBM and combination of EMD and DBBM did not present predictably complete healing of the defects. All the defects where GBR was applied alone or combined with DBBM and/or EMD presented always complete healing (P<0.05). The combined use of GBR with EMD and/or DBBM did not offer any significant advantage above GBR alone in terms of healing of the length and the width of the defect. However, the vertical dimension of the defect was significantly higher (P<0.05) in the GBR-treated specimens of Groups C and D. The histological analysis supported these findings. CONCLUSION: The predictability of bone formation in critical-size defects depends mainly on the presence or absence of barrier membranes (GBR). The combined use with deproteinized bovine bone mineral and/or enamel matrix proteins did not significantly enhance the potential for complete healing provided by the GBR procedure.
Asunto(s)
Regeneración Ósea , Sustitutos de Huesos , Regeneración Tisular Dirigida/métodos , Membranas Artificiales , Animales , Materiales Biocompatibles , Matriz Ósea/trasplante , Trasplante Óseo/métodos , Bovinos , Colágeno , Proteínas del Esmalte Dental , Masculino , Minerales , Distribución Aleatoria , Ratas , Ratas Wistar , Reproducibilidad de los Resultados , Cráneo/cirugía , Estadísticas no ParamétricasRESUMEN
BACKGROUND: There are results suggesting that differences regarding bone-inducing potential, in terms of amount and/or rate of bone formation, exist between demineralized bone matrices (DBMs) of different embryonic origins. PURPOSE: The aim of the present study was to examine whether the embryonic origin of DBM affects bone formation when used as an adjunct to guided tissue regeneration (GTR). MATERIALS AND METHODS: Endomembranous (EM) and endochondral (ECH) DBMs were produced from calvarial and long bones of rats, respectively. Prior to the study the osteoinductive properties of the DBMs were confirmed in six rats following intramuscular implantation. Following surgical exposure of the mandibular ramus, a rigid hemispheric Teflon capsule loosely packed with a standardized quantity of DBM was placed with its open part facing the lateral surface of the ramus in both sides of the jaw in 30 rats. In one side of the jaw, chosen at random, the capsule was filled with EM-DBM, whereas in the other side ECH-DBM was used. Groups of 10 animals were sacrificed after healing periods of 1, 2, and 4 months, and undecalcified sections of the capsules were produced and subjected to histologic analysis and computer-assisted planimetric measurements. RESULTS: During the experiment increasing amounts of newly formed bone were observed inside the capsules in both sides of the animals' jaws. Limited bone formation was observed in the 1- and 2-month specimens, but after 4 months of healing, the newly formed bone in the ECH-DBM grafted sides occupied 59.1% (range 45.6-74.7%) of the area created by the capsule versus 46.9% (range 23.0-64.0%) in the EM-DBM grafted sides (p =.01). CONCLUSION: It is concluded that the embryonic origin of DBM influences bone formation by GTR and that ECH-DBM is superior to EM-DBM.
Asunto(s)
Matriz Ósea/trasplante , Osteogénesis/fisiología , Animales , Matriz Ósea/embriología , Matriz Ósea/patología , Fémur , Procesamiento de Imagen Asistido por Computador , Masculino , Mandíbula/cirugía , Osificación Heterotópica/fisiopatología , Músculos Pectorales/cirugía , Distribución Aleatoria , Ratas , Ratas Wistar , Cráneo , Estadísticas no Paramétricas , Tibia , Factores de Tiempo , Conservación de Tejido , Cicatrización de Heridas/fisiologíaRESUMEN
Preservation of alveolar bone volume following tooth extraction facilitates subsequent placement of dental implants and leads to an improved esthetic and functional prosthodontic result. The aim of the present study was to assess bone formation in the alveolus and the contour changes of the alveolar process following tooth extraction. The tissue changes after removal of a premolar or molar in 46 patients were evaluated in a 12-month period by means of measurements on study casts, linear radiographic analyses, and subtraction radiography. The results demonstrated that major changes of an extraction site occurred during 1 year after tooth extraction.
Asunto(s)
Proceso Alveolar/fisiopatología , Encía/patología , Extracción Dental , Adulto , Anciano , Proceso Alveolar/diagnóstico por imagen , Diente Premolar/cirugía , Remodelación Ósea/fisiología , Femenino , Estudios de Seguimiento , Recesión Gingival/clasificación , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Modelos Dentales , Diente Molar/cirugía , Osteogénesis/fisiología , Estudios Prospectivos , Radiografía , Estadísticas no Paramétricas , Técnica de Sustracción , Cicatrización de Heridas/fisiologíaRESUMEN
OBJECTIVES: Grafting of deproteinized bovine bone or bioactive glass has been suggested as an adjunct to guided tissue regeneration (GTR) for the treatment of periodontal and peri-implant bone defects but the influence of these materials on bone formation is not clarified. The aim of the study was to examine the long-term influence of deproteinized bovine bone (Bio-Oss) or bioactive glass (Biogran) on bone formation produced by GTR. MATERIAL AND METHODS: Eighteen rats were used. Following incisions along the inferior border of the mandible, muscle-periosteal flaps were raised to expose the mandibular ramus. Rigid, hemispherical, Teflon capsules (6 mm internal diameter and 1 mm peripheral collar) loosely packed with a standardized quantity of either deproteinized bovine bone (test group 1) or bioactive glass (test group 2), or empty capsules (control group) were then placed with their open part facing the lateral surface of the ramus (one capsule per animal). After 1 year, the capsules were removed by a reentry operation, and the animals were sacrificed. Histological specimens of the augmented sites were prepared, and the volumes of (1). newly formed bone, (2). graft particles, and (3). soft connective tissue in the space originally created by the capsule were estimated by a point-counting technique in three to four histological sections, taken by uniformly random sampling. RESULTS: Limited bone formation was observed in the two test groups. The major part of the space originally created by the capsules was occupied by graft particles embedded in connective tissue. The mean volume of newly formed bone occupied only 23% of the total space in the animals grafted with Bio-Oss and 12.6% in those grafted with Biogran. In the control animals, however, 88.2% (p<0.01) of the space was filled with newly formed bone. There were no signs of ongoing bone formation in any of the three experimental groups. CONCLUSION: It is concluded that grafting of Bio-Oss or Biogran as an adjunct to GTR arrests bone formation.
Asunto(s)
Sustitutos de Huesos/toxicidad , Regeneración Tisular Dirigida , Osteogénesis/efectos de los fármacos , Animales , Bovinos , Vidrio , Implantes Experimentales , Mandíbula , Minerales/toxicidad , Ratas , Ratas WistarRESUMEN
PURPOSE: The aim of this study was to compare bone healing and crestal bone changes following immediate (Im) versus delayed (De) placement of titanium dental implants with acid-etched surfaces (Osseotite) in extraction sockets. MATERIALS AND METHODS: Forty-six patients were randomly allocated to the Im or De group (n = 23 per group) and received 1 implant at the incisor, canine, or premolar region of the maxilla or the mandible. The implants were placed an average of 10 days following tooth extraction in the Im group and approximately 3 months after extraction in the De group. The widths (parallel and perpendicular to the implant) and the depth of marginal bone defects around the implants were measured clinically just after placement and 3 months later at the abutment surgery. The crestal bone changes mesially and distally to the implants were evaluated radiographically by linear measurements. RESULTS: The survival rates were 91% in the Im group and 96% in the De group. In the Im group, the mean reductions in parallel width, perpendicular width, and depth of the largest defect of each implant amounted to 48% (from 4.4 to 2.3 mm), 59% (from 2.2 to 0.9 mm), and 48% (from 6.9 to 3.6 mm), respectively. The corresponding mean reductions in the De group amounted to 39% (from 3.1 to 1.9 mm), 77% (from 1.3 to 0.3 mm), and 34% (from 4.4 to 2.9 mm). The reduction over time was statistically significant in both groups (P < .04). For both groups, a higher degree of bone healing was achieved in the infrabony defects (> 60% for depth) than in dehiscence-type defects (approximately 25%). Furthermore, 70% of the 3-wall infrabony defects with a parallel width of up to 5 mm, a depth of maximum 4 mm, and a perpendicular width of maximum 2 mm had a capacity of spontaneous healing within a period of 3 months. DISCUSSION AND CONCLUSION: New bone formation occurs in infrabony defects associated with immediately placed implants in extraction sockets.
Asunto(s)
Pérdida de Hueso Alveolar/fisiopatología , Regeneración Ósea , Implantación Dental Endoósea/métodos , Implantes Dentales , Alveolo Dental , Adulto , Anciano , Pérdida de Hueso Alveolar/diagnóstico por imagen , Pérdida de Hueso Alveolar/etiología , Fracaso de la Restauración Dental , Femenino , Humanos , Masculino , Persona de Mediana Edad , Oseointegración , Radiografía , Factores de Tiempo , Titanio , Extracción Dental/efectos adversosRESUMEN
The aim of this study was to evaluate the effect of: guided tissue regeneration (GTR) alone, implantation of demineralized bone matrix (DBM) alone, and of the combined treatment on the healing of craniectomy defects involving the sagittal cranial suture, and to examine subsequent calvarial growth. Sixty four-week-old rats were used in the study. These animals were randomly assigned to five groups (A-E) of 12 animals. In four groups (A-D), a calvarial defect (5.0 mm) involving the sagittal suture was produced in each animal. Group A: The defect was left untreated. Group B: DBM was implanted into the defect. Group C: The cerebral and the galeal aspect of the defect was covered with an e-PTFE membrane. Group D: The defect was treated with the double membrane technique combined with implantation of DBM. Group E: The animals were sham-operated, no defect was created. In all groups, two gutta-percha points were placed to indicate the lateral borders of the parietal bones. Histological analysis 4 months following surgery showed that the untreated cranial defects (A) had healed with fibrous connective tissue in the midportion of the defect. The DBM grafted defects (B) healed either completely with bone containing DBM particles or partially with bone and connective tissue. The defects (D) treated with DBM combined with GTR healed completely with bone, while the defects (C) treated with membranes alone healed with bone but a suture-like tissue similar to the normal sagittal suture of the sham-operated controls (E) was always present in the midportion of the defect. Cephalometric radiography demonstrated that the membrane-treated (C) and the sham-operated animals (E) exhibited similar coronal growth of the cranial vault following treatment. Craniometric measurements on chemically defleshed specimens showed that sham-operated and membrane-treated animals presented significantly more biparietal width than the animals treated with DBM alone or DBM combined with GTR (P < 0.05). The results demonstrated that predictable osseous healing including the formation of a sagittal suture can be accomplished in craniectomy defects by GTR, and undisturbed cranial growth reestablished. The treatment of the defects with DBM alone or DBM combined with GTR resulted in craniosynostosis and reduced cranial growth.
Asunto(s)
Enfermedades Óseas/cirugía , Matriz Ósea/trasplante , Regeneración Ósea/fisiología , Sustitutos de Huesos/uso terapéutico , Suturas Craneales/cirugía , Membranas Artificiales , Hueso Parietal/cirugía , Politetrafluoroetileno , Cráneo/crecimiento & desarrollo , Análisis de Varianza , Animales , Enfermedades Óseas/fisiopatología , Cefalometría , Tejido Conectivo/fisiopatología , Suturas Craneales/crecimiento & desarrollo , Suturas Craneales/fisiopatología , Craneotomía , Modelos Animales de Enfermedad , Masculino , Osteogénesis/fisiología , Hueso Parietal/crecimiento & desarrollo , Hueso Parietal/fisiopatología , Distribución Aleatoria , Ratas , Ratas Wistar , Estadísticas no Paramétricas , Cicatrización de Heridas/fisiologíaRESUMEN
The aim of the present study was to evaluate the effect of using mandibular cortical bone grafts covered with e-PTFE membranes for maxillary alveolar ridge augmentation, in comparison with the use of mandibular cortical grafts alone. The experiment was carried out in 20 rats. At one side of the maxillary jaw, the edentulous alveolar ridge between the incisor and the first molar was augmented by means of an autogenous mandibular bone graft, which was fixed with a titanium microimplant and covered with a Teflon membrane. The contralateral side, serving as control, was treated the same way, except for the placement of a membrane. Histological analysis at 15, 30, 60 and 90 days after surgery demonstrated that, in situations where the membrane was not exposed to the oral cavity during healing, the mandibular bone grafts presented no resorption and were in continuity with the maxillary bone at the recipient site. In situations where the membrane had become exposed, however, the bone grafts presented extensive resorption and lack of continuity with the bone at the recipient site. These latter findings were similar to those made at the non-membrane-treated side. The results indicate that the volume of autogenous bone graft used for alveolar ridge augmentation can be retained by covering the graft with a membrane, provided that the membrane is properly adapted and is kept covered with mucosa during healing.