Measurement of the Force Required to Extract the Mandibular First Molar from Its Socket in the Dissected Jaw of Growing Young Rats

Komatsu, Koichiro; Ohshima, S.; Chiba, M.

doi:10.1111/j.1741-2358.1990.tb00251.x

Cited by 9 publications

(3 citation statements)

References 36 publications

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“…In order to elucidate the tooth support mechanisms, Chiba's group systematically investigated the effects, on the mechanical properties of the PDL, of various experimental factors [4] such as periodontal disease [10, 22], hypofunction [18, 35, 36], orthodontic forces [37–39], treatment with inhibitors (lathyrogens) of collagen cross-linking and an inhibitor (hydrocortisone) of collagen degradation or turnover [8, 40–43], age [7, 17, 20, 44, 45], and root levels [19, 21]. They found that the mechanical properties were sensitive to both experimental alterations and to differences in the content, direction, and organisation of the collagen fibre components of the PDL.…”

Section: The Mechanical Strength Of the Pdlmentioning

confidence: 99%

Mechanical Strength and Viscoelastic Response of the Periodontal Ligament in Relation to Structure

Komatsu¹

2010

Journal of Dental Biomechanics

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The mechanical strength of the periodontal ligament (PDL) was first measured as force required to extract a tooth from its socket using human specimens. Thereafter, tooth-PDL-bone preparations have extensively been used for measurement of the mechanical response of the PDL. In vitro treatments of such specimens with specific enzymes allowed one to investigate into the roles of the structural components in the mechanical support of the PDL. The viscoelastic responses of the PDL may be examined by analysis of the stress-relaxation. Video polarised microscopy suggested that the collagen molecules and fibrils in the stretched fibre bundles progressively align along the deformation direction during the relaxation. The stress-relaxation process of the PDL can be well expressed by a function with three exponential decay terms. Analysis after in vitro digestion of the collagen fibres by collagenase revealed that the collagen fibre components may play an important role in the long-term relaxation component of the stress-relaxation process of the PDL. The dynamic measurements of the viscoelastic properties of the PDL have recently suggested that the PDL can absorb more energy in compression than in shear and tension. These viscoelastic mechanisms of the PDL tissue could reduce the risk of injury to the PDL.

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Section: The Mechanical Strength Of the Pdlmentioning

confidence: 99%

Mechanical Strength and Viscoelastic Response of the Periodontal Ligament in Relation to Structure

Komatsu¹

2010

Journal of Dental Biomechanics

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“…Furthermore, the present study established a generalized and robust model for recording the force applied during the tooth extraction process. The latter comprises an important contribution to the scholarship aimed at understanding PDL structure and function [ 28 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ]. Our setup is generic and can be extended to a broad range of research applications.…”

Section: Discussionmentioning

confidence: 99%

Collagenase Administration into Periodontal Ligament Reduces the Forces Required for Tooth Extraction in an Ex situ Porcine Jaw Model

Tohar

Alali

Ansbacher

et al. 2022

JFB

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Minimally invasive exodontia is among the long-sought-for development aims of safe dental medicine. In this paper, we aim, for the first time, to examine whether the enzymatic disruption of the periodontal ligament fibers reduces the force required for tooth extraction. To this end, recombinantly expressed clostridial collagenase G variant purified from Escherichia coli was injected into the periodontal ligament of mesial and distal roots of the first and second split porcine mandibular premolars. The vehicle solution was injected into the corresponding roots on the contralateral side. Following sixteen hours, the treated mandibles were mounted on a loading machine to measure the extraction force. In addition, the effect of the enzyme on the viability of different cell types was evaluated. An average reduction of 20% in the applied force (albeit with a large variability of 50 to 370 newton) was observed for the enzymatically treated roots, reaching up to 50% reduction in some cases. Importantly, the enzyme showed only a minor and transient effect on cellular viability, without any signs of toxicity. Using an innovative model enabling the analytical measurement of extraction forces, we show, for the first time, that the enzymatic disruption of periodontal ligament fibers substantially reduces the force required for tooth extraction. This novel technique brings us closer to atraumatic exodontia, potentially reducing intra- and post-operative complications and facilitating subsequent implant placement. The development of novel enzymes with enhanced activity may further simplify the tooth extraction process and present additional clinical relevance for the broad range of implications in the oral cavity.

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“…Also this seemingly important aspect of dental mechanics has hardly been explored. Some results, in terms of forces only, are reported in [Chiba et al 1980;Komatsu et al 1990;Lehtinen and Ojala 1980;Ahel et al 2006]. Nothing seems to exist in terms of displacements corresponding to applied forces.…”

mentioning

confidence: 99%

Untitled

2014

J. Mech. Mater. Struct.

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Buckling is an instability encountered in a wide variety of problems, both in engineering and biology. Almost all engineering structures are designed with adequate safety factors to prevent failure due to buckling, yielding or dynamic loads. In a classical sense, design for buckling is done by carefully controlling the modulus of elasticity, moment of inertia and the length of the structure. Further, such an approach assumes the material to be homogeneous and does not generally account for the microstructural details of the column. In this paper, we study the buckling of inhomogeneous columns with a two-phase checkerboard microstructure. Monte Carlo simulations are used to generate microstructures with arbitrary volume fractions and phase contrasts (ratio of the modulus of individual phases). An analytical form is obtained for the ensemble averaged critical buckling load based on the results of over 18,000 eigenvalue problems at arbitrary volume fractions, phase contrasts and distributions. Further, microstructural realizations that correspond to the highest buckling load (best design) and the lowest buckling load (worst design) are identified and the corresponding distribution of individual phases is determined. Finally, the statistical nature of the critical buckling load is discussed by computing the statistical moments that include the mean and coefficient of variation.

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Measurement of the Force Required to Extract the Mandibular First Molar from Its Socket in the Dissected Jaw of Growing Young Rats

Cited by 9 publications

References 36 publications

Mechanical Strength and Viscoelastic Response of the Periodontal Ligament in Relation to Structure

Mechanical Strength and Viscoelastic Response of the Periodontal Ligament in Relation to Structure

Collagenase Administration into Periodontal Ligament Reduces the Forces Required for Tooth Extraction in an Ex situ Porcine Jaw Model

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