Influence of implant length on implant primary and secondary stability / Influencia del largo del implante sobre la estabilidad primaria y secundaria

ABSTRACT Introduction: Implant stability can be measured at the moment of implant placement or once the osseointegration process is in progress. Many factors should be considered, including bone quality, osteotomy preparation, implant design, implant surface enhancement, and implant length and diameter. Objective: Determine the influence of implant length on primary and secondary stability in type II and type III bones using resonance frequency analysis method. Methods: A prospective study was conducted in the department of Oral maxillofacial Implantology at the School of Dentistry of the University of Chile between April 2006 and June 2007. 38 screw type implants were placed in the maxilla and mandible, in type II and type III bones. 21 implants had an average contact area of 237 mm2 including 2 sizes (3.75mm and a length of 13mm and 15mm) and 17 implants had an average contact area of 129 mm2 (diameter of 3.75mm and a length of 7mm). Implant primary stability was measured by the Implant Stability Quotient value. Resonance frequency measurements were recorded using Osstell™ Mentor. Secondary implant stability was recorded between 4 to 6 months after the implant placement. Results: For implants with an average contact area of 237 mm2 the stability 1 average value was 71,37 and the stability 2 average value was 66,6. For implants with an average contact area of 129 mm2 the stability 1 average value was 67,47 and the stability 2 average value was 68,08. Conclusion: Implant length does not influence primary and secondary stability in type II and type III bones.

RESUMEN Introducción: La estabilidad del implante se puede medir al momento de colocarlo o una vez que el proceso de osteointegración está en curso. Se deben considerar muchos factores, incluida la calidad ósea, la superficie y diseño del implante, la longitud y el diámetro. Objetivo: Determinar la influencia de la longitud del implante en la estabilidad primaria y secundaria en huesos tipo II y tipo III mediante el método de análisis de frecuencia de resonancia. Métodos: Estudio prospectivo en el departamento de Implantología Oral maxilofacial de la Facultad de Odontología de la Universidad de Chile, entre abril 2006 y junio 2007. Se colocaron 38 implantes tipo tornillo en maxilar y mandíbula, en huesos tipo II y tipo III. 21 implantes tenían un área de contacto promedio de 237 mm2, incluidos 2 tamaños (3,75 mm y una longitud de 13 mm y 15 mm) y 17 implantes tenían un área de contacto promedio de 129 mm2 (diámetro de 3,75 mm y una longitud de 7 mm). La estabilidad primaria del implante se midió mediante el valor cociente de estabilidad del implante y la estabilidad secundaria. Resultados: Para implantes con un área de contacto promedio de 237 mm2, la estabilidad 1 fue de 71,37 y la estabilidad 2 fue de 66,6. Para implantes con un área de contacto promedio de 129 mm2, la estabilidad 1 fue de 67,47 y la estabilidad 2 fue de 68,08. Conclusión: La longitud del implante no influye en la estabilidad primaria y secundaria en los huesos tipo II y tipo III.

Influence of the length and location of implants on distal extension removable partial dentures: finite element analysis

PURPOSE: To evaluate the effects of implant location and length on stress distribution and displacement in osseointegrated-implants that were associated with mandibular distal extension removable partial dentures (DERPD). MATERIALS AND METHODS: A sagittally cut model with the #33, #34 teeth and a removable partial denture of the left mandible was used. Seven models were designed with NX 9.0. Models A, B, C had implants with lengths of 11 ,6, 4 mm, respectively, under the denture base of the #37 artificial tooth. Models D, E, F had implants with lengths of 11, 6, 4 mm, respectively, under the denture base of the #36 artificial tooth. Model G did not have any implants. Axial force (250 N) was loaded on #36 central fossa. The finite element analysis was performed with MSC Nastran. Von Mises stress maps were plotted to visualize the results. RESULTS: The models of #37 implant placement showed much lower stress concentration on the surrounding bone of the implant compared with #36. The #36 implant position tended to reduce displacement more than #37. CONCLUSION: When an IARPD is designed, the distal positioning of implant placement has more advantages in the edentulous bone of DERPD on the prognosis of short implants and the stress distribution of edentulous alveolar bone. Using implants with longer lengths are important for stress distribution. However, Additional studies are necessary of the effects of length on implant survival.

Retrospective study of implant stability according to the implant length, diameter and position / 대한치과보철학회지

PURPOSE: The aim of this retrospective study was to evaluate the influence of implant diameter, length and placement to implant stability. MATERIALS AND METHODS: Total 90 implants (US II plus(TM), Osstem co, Busan, Korea) of 72 patients were determined as experimental samples. The factors of diameters(o 4 mm, o 5 mm), lengths (10 mm, 11.5 mm, 13 mm), and implant placement (maxilla, mandible) were analyzed. The stability of the implants was measured by resonance frequency analysis (RFA) at the time of implant placement and impression taking. The difference of ISQ values according to patient's gender was evaluated by Independent t-test. ISQ values were compared between implant diameter, length and placement using one-way ANOVA and Tukey HSD test (alpha=.05). To compare ISQ values between at the time of surgery and impression taking, paired t-tests were used (alpha=.05). RESULTS: The change of implant length did not show significant different on the ISQ value (P>.05). However, 5 mm diameter implants had higher ISQ values than 4 mm diameter implants (P<.05). Implants placed on the mandible showed significantly higher ISQ values than on the maxilla (P<.05). CONCLUSION: In order to increase implant stability, it is better to select the wider implant, and implants placed on mandible are possible to get higher stability than maxilla. ISQ values at impression taking showed higher implant stability than ISQ values at implant placement, it means that RFA is clinically effective method to evaluate the change of implant stability through the osseointegration. The consideration of the factors which may affect to the implant stability will help to determine the time of load applying and increase the implant success rate.

Assessment of demographic and clinical data related to dental implants in a group of Turkish patients treated at a university clinic

PURPOSE: This retrospective study analyzed the distribution of the dental implants with regards to age and gender of the patients and type of indication for the implant therapy, as well as the location, dimension and type of the implants. MATERIALS AND METHODS: The data of demographics (age and gender), type of indication for implant therapy, anatomical location, dimensions (length and diameter) and type (bone and tissue level) of 1616 implants were recorded from patient charts between January 2000 and January 2010. Descriptive statistics were analyzed using a chi-squared test for demographic parameters, type of indication, tooth position, anatomical location, implant dimensions and type (alpha=.05). RESULTS: The patient pool comprised of 350 women and 266 men, with a mean age of 52.12 +/- 13.79 years. The difference in n% of the implants of the age groups was statistically significant between the types of indications. The difference in the position of the implants was statistically significant between the n% of the implants of all age groups. Gender did not significantly vary, except that the diameter of the implants was significantly higher for the standard diameter implants in males. The difference between the implant positions was statistically significant when considered according to indication. The relationship between implant length and anatomical location was statistically significant. CONCLUSION: The indication for dental implant use is age dependent and the type and size of the implant seems to be strongly related to the location of the implant.

A comparative study on the initial stability of different implants placed above the bone level using resonance frequency analysis

PURPOSE: This study evaluated the initial stability of different implants placed above the bone level in different types of bone. MATERIALS AND METHODS: As described by Lekholm and Zarb, cortical layers of bovine bone specimens were trimmed to a thickness of 2 mm, 1 mm or totally removed to reproduce bone types II, III, and IV respectively. Three Implant system (Branemark System(R) Mk III TiUnite(TM), Straumann Standard Implant SLA(R), and Astra Tech Microthread(TM)-OsseoSpeed(TM)) were tested. Control group implants were placed in level with the bone, while test group implants were placed 1, 2, 3, and 4 mm above the bone level. Initial stability was evaluated by resonance frequency analysis. Data was statistically analyzed by one-way analysis of variance in confidence level of 95%. The effective implant length and the Implant Stability Quotient (ISQ) were compared using simple linear regression analysis. RESULTS: In the control group, there was a significant difference in the ISQ values of the 3 implants in bone types III and IV (P<.05). The ISQ values of each implant decreased with increased effective implant length in all types of bone. In type II bone, the decrease in ISQ value per 1-mm increase in effective implant length of the Branemark and Astra implants was less than that of the Straumann implant. In bone types III and IV, this value in the Astra implant was less than that in the other 2 implants. CONCLUSION: The initial stability was much affected by the implant design in bone types III, IV and the implant design such as the short pitch interval was beneficial to the initial stability of implants placed above the bone level.

An analysis of ITI implants placed in korean patients / 대한치주과학회지

The aim of this study was to analyze various data of 120 non-submerged ITI implants placed in 64 korean adults. The data were retrieved from patients' charts and registered in the computer and coded for a statistical analysis. The results revealed that the most common type of edentulism was a distal extension case, and the largest number of implants were placed in the mandibular first molar position. Implants were placed more frequently in mandibular, posterior position than maxillary, anterior position, respectively. With respect to the implant diameter and length, an implant with 4.1mm in diameter and more than 10mm in length was the most common. Since a molar position was the most prevalent position for implant placement in korean patients, clinicians should be careful about implant diameter which can resist a strong occlusal force expected in the molar position. In addition, the distance to the mandibular canal and the floor of maxillary sinus should be considered to avoid possible damages, such as nerve injury and sinus perforation in selecting a proper implant length.