Paolo Arosio

A torque-measuring micromotor provides operator independent measurements marking four different density areas in maxillae

PURPOSE Bone density at implant placement site is a key factor to obtain the primary stability of the fixture, which, in turn, is a prognostic factor for osseointegration and long-term success of an implant supported rehabilitation. Recently, an implant motor with a bone density measurement probe has been introduced. The aim of the present study was to test the objectiveness of the bone densities registered by the implant motor regardless of the operator performing them. MATERIALS AND METHODS A total of 3704 bone density measurements, performed by means of the implant motor, were registered by 39 operators at different implant sites during routine activity. Bone density measurements were grouped according to their distribution across the jaws. Specifically, four different areas were distinguished: a pre-antral (between teeth from first right maxillary premolar to first left maxillary premolar) and a sub-antral (more distally) zone in the maxilla, and an interforaminal (between and including teeth from first left mandibular premolar to first right mandibular premolar) and a retroforaminal (more distally) zone in the lower one. A statistical comparison was performed to check the inter-operators variability of the collected data. RESULTS The device produced consistent and operator-independent bone density values at each tooth position, showing a reliable bone-density measurement. CONCLUSION The implant motor demonstrated to be a helpful tool to properly plan implant placement and loading irrespective of the operator using it.

The effect of undersizing and tapping on bone to implant contact and implant primary stability: A histomorphometric study on bovine ribs

PURPOSE Implant site preparation may be adjusted to achieve the maximum possible primary stability. The aim of this investigation was to study the relation among bone-to-implant contact at insertion, bone density, and implant primary stability intra-operatively measured by a torque-measuring implant motor, when implant sites were undersized or tapped. MATERIALS AND METHODS Undersized (n=14), standard (n=13), and tapped (n=13) implant sites were prepared on 9 segments of bovine ribs. After measuring bone density using the implant motor, 40 implants were placed, and their primary stability assessed by measuring the integral of the torque-depth insertion curve. Bovine ribs were then processed histologically, the bone-to-implant contact measured and statistically correlated to bone density and the integral. RESULTS Bone-to-implant contact and the integral of the torque-depth curve were significantly greater for undersized sites than tapped sites. Moreover, a correlation between bone to implant contact, the integral and bone density was found under all preparation conditions. The slope of the bone-to-implant/density and integral/density lines was significantly greater for undersized sites, while those corresponding to standard prepared and tapped sites did not differ significantly. CONCLUSION The integral of the torque-depth curve provided reliable information about bone-to-implant contact and primary implant stability even in tapped or undersized sites. The linear relations found among the parameters suggests a connection between extent and modality of undersizing and the corresponding increase of the integral and, consequently, of primary stability. These results might help the physician determine the extent of undersizing needed to achieve the proper implant primary stability, according to the planned loading protocol.

The insertion torque-depth curve integral as a measure of implant primary stability: An in vitro study on polyurethane foam blocks

Statement of problem. Recent research has shown that dynamic parameters correlate with insertion energy—that is, the total work needed to place an implant into its site—might convey more reliable information concerning immediate implant primary stability at insertion than the commonly used insertion torque (IT), the reverse torque (RT), or the implant stability quotient (ISQ). Yet knowledge on these dynamic parameters is still limited. Purpose. The purpose of this in vitro study was to evaluate whether an energy‐related parameter, the torque‐depth curve integral (I), could be a reliable measure of primary stability. This was done by assessing if (I) measurement was operator‐independent, by investigating its correlation with other known primary stability parameters (IT, RT, or ISQ) by quantifying the (I) average error and correlating (I), IT, RT, and ISQ variations with bone density. Material and methods. Five operators placed 200 implants in polyurethane foam blocks of different densities using a micromotor that calculated the (I) during implant placement. Primary implant stability was assessed by measuring the ISQ, IT, and RT. ANOVA tests were used to evaluate whether measurements were operator independent (P>.05 in all cases). A correlation analysis was performed between (I) and IT, ISQ, and RT. The (I) average error was calculated and compared with that of the other parameters by ANOVA. (I)‐density, IT‐density, ISQ‐density, and RT‐density plots were drawn, and their slopes were compared by ANCOVA. Results. The (I) measurements were operator independent and correlated with IT, ISQ, and RT. The average error of these parameters was not significantly different (P>.05 in all cases). The (I)‐density, IT‐density, ISQ‐density, and RT‐density curves were linear in the 0.16 to 0.49 g/cm3 range, with the (I)‐density curves having a significantly greater slope than those regarding the other parameters (P≤.001 in all cases). Conclusions. The torque‐depth curve integral (I) provides a reliable assessment of primary stability and shows a greater sensitivity to density variations than other known primary stability parameters.

Evaluation of Peri-implant Bone Stress on D1 Bone Using a Computerized Torque-Measuring Implant Motor: A Study on Photoelastic Resin Blocks

PURPOSE Recently, a torque-measuring micromotor that calculates the integral (I) of torque-depth curve at implant insertion was developed. This device was used to investigate the correlation between (I) and mechanical stress in photoelastic resin blocks with the density of D1 bone. MATERIALS AND METHODS Using the micromotor, 40 implants (3.75 × 12 mm) were placed in 40 D1 blocks that had been prepared in four different ways. Four groups of 10 blocks each were prepared according to tunnel length (12 or 14 mm) and debris removal (yes or no). After insertion, peri-implant mechanical stress and its correlation with (I) were assessed by photoelastic and linear regression analysis, respectively. Analysis of variance (ANOVA) and Kruskal-Wallis tests investigated differences in mechanical stress patterns and dynamic parameters among the groups. RESULTS (I) significantly correlated with mechanical stress in D1 resin under all conditions, except for 12-mm implant sites still containing debris. The correlation was significant concerning the whole dataset (r = 0.979) and separately for the coronal (r = 0.940), middle (r = 0.964), and apical (r = 0.948) portions of the implants. Peak torque did not correlate significantly with peri-implant mechanical stress. Longer implant sites and debris removal were significantly associated with lower peri-implant mechanical stress. CONCLUSION (I) provides a reliable measure of mechanical stress in D1 bone during implant placement. Preparation of longer osteotomies and routine removal of all debris might reduce peri-implant bone stress significantly.

Misura intraoperatoria della densità ossea e della stabilità implantare primaria: un nuovo approccio chirurgico

Riassunto Obiettivi Obiettivo di questo studio osservazionale e testare un micromotore implantare dotato di una sonda di misura della densita ossea e della stabilita implantare primaria. Materiali e metodi Due operatori hanno misurato la densita ossea in corrispondenza di 727 siti implantari durante l’esecuzione di altrettante chirurgie di posizionamento. I pazienti sono stati controllati ogni 6 mesi e i parametri di successo implantare sono stati valutati secondo i criteri di Albrektsson e Zarb. Risultati Le misure di densita si distribuiscono nei mascellari in linea con quanto gia pubblicato. Dopo 18 mesi i risultati di successo e sopravvivenza implantare erano rispettivamente del 99,2% e del 100%. Conclusioni Il sistema di misura e riproducibile e permette di eseguire la preparazione del sito secondo parametri oggettivi.