Retrospective multicenter study of 230 6-mm SLA-surfaced implants with 1- to 6-year follow-up.

PURPOSE: Using short implants poses a challenge in implant surgery. Implant surfaces have evolved, making it possible to improve the success of short implants substantially. However, there is still little information about the long-term predictability achieved with short, rough-surfaced implants. The objective of this study was to evaluate the long-term survival rate of 6-mm rough implants. MATERIALS AND METHODS: A retrospective multicenter analysis of the survival of short 6-mm SLA-surfaced implants was conducted. A total of 230 implants placed in 159 patients were included. The follow-up time ranged between 1 and 6 years. RESULTS: Seven of the 230 implants failed, which gives a cumulative survival rate of 96.4%. Two hundred and fourteen implants were placed in the mandible (93.1%), as opposed to 16 placed in the maxilla (6.9%). Five implants failed during the osseointegration period, and two failed after receiving the prosthetic load. No statistically significant differences were found (P < .44). Of the loaded implants, 209 were splinted to other implants, as opposed to 14 that were not. One implant failed in each group, resulting in a 99.5% for the splinted implants and 92.9% for the unsplinted implants. No statistically significant differences were found between the splinted and unsplinted groups (P < .12). CONCLUSIONS: The short implants used in this study displayed high longterm predictability when placed in the mandible and splinted. There is insufficient- information to extrapolate these results to the maxilla and non-splinted implants.

Flapless immediate implant placement with or without immediate loading: a histomorphometric study in beagle dog.

OBJECTIVE: To assess the osseointegration process after flapless immediate implant placement with or without immediate loading. MATERIAL AND METHODS: This study was carried out on six beagle dogs. Four implants were placed in the lower jaw (two per side) in each dog immediately after tooth extraction (3rd and 4th premolars). Flapless immediate implant placement was performed in one hemimandible (control). The same procedure was carried out in the contra-lateral side and immediate prosthesis was connected with occlusal contacts (test). After 3 months of healing, the dogs were sacrificed for histomorphometric analysis. RESULTS: Twelve implants were placed in each group. None of the implants and prosthesis was lost. The percentage of bone-to-implant contact (BIC %) was similar in both groups: 82.72% (test) and 76.96% (control). Differences were found neither in the inter-thread bone area (test: 83.45%, control: 80.65%) nor in peri-implant bone area (test: 94.37%, control: 94.81%). CONCLUSION: In this animal model where the implants were well within the confines of the extraction socket, osseointegration following flapless immediate implant placement and loading can be achieved in the same manner as immediate placement without loading.

Histomorphometric assessment in human cadavers of the peri-implant bone density in maxillary tuberosity following implant placement using osteotome and conventional techniques.

OBJECTIVE: To evaluate and compare peri-implant bone condensation in the maxillary tuberosity of human cadavers following the osteotome and standard drilling techniques, and to determine whether peri-implant bone condensation following the osteotome technique is localized or homogeneous. MATERIAL AND METHODS: Twenty-four cylinder-threaded titanium implants (12 on each side) were placed in the left (standard technique) and right (osteotome technique with tapered osteotomes for bone condensation, Straumann) maxillary tuberosities of 12 edentulous posterior maxillae of deceased people who had bequeathed their bodies to the University of Santiago de Compostela for medical-scientific research. After surgery, the implants were removed with the surrounding bone, prepared using sawing and grinding technique and examined histomorphometrically. The bone density (bone area/analyzed area) of the entire, periapical (fifth apical) and pericylinder peri-implant areas was calculated, statistically analyzed and compared with the bone density of the host cancellous maxillary bone. RESULTS: The bone density of the entire peri-implant area was statistically found to be greater with the osteotome technique (39.38 +/- 9.67) than with conventional drilling technique (31.06 +/- 5.9). This difference was greatest for the periapical zone (53.32 +/- 12.26 vs. 34.18 +/- 6.34). Nonetheless, in the pericylinder area no significant difference was found between the two techniques (32.30 +/- 8.74 vs. 30.34 +/- 7.2). CONCLUSION: Peri-implant bone condensation following the osteotome technique is not homogeneously observed through the entire peri-implant area. A greater bone density was achieved only in the fifth apical peri-implant area.

Subunidad alfa de coriogonadotropina (alfa-HCG) en el embarazo normal / Subunit of alpha chronical gonadotropin (alfa-HCG) in normal pregnancy

Se cuantificaron niveles de subnidades alfa y beta de gonadotropina coriónicas humana (HCG) por el método de radioinmunoanálisis en mujeres embarazadas normales, durante todo el periodo gestacional, a fin de conocer las diferencias existentes en una población gestante escogida en el Instituto Nacional de Perinatología. Confirmamos una disociación acentuada de los niveles de HCG-alfa y beta; se encontró la primera más elevada que la segunda, lo que fue más notório en la segunda mitad de la gestación (p = < 0.0001). Sin embargo, la subnidad alfa-HCG tendió a descender entre las semanas 35 a 37, y posteriormente se elevó de nuevo. La trascendencia de este fenómeno es desconocida