Development of new artificial models for splint rigidity evaluation

Effect of wire diameter and extent of wire composite splint on the mobility of luxated and anchor primary teeth: A typodont study

BACKGROUND/AIMS

The recommendations for splinting are well established for the injuries of permanent dentition; however, ambiguity still exists for the injuries in primary dentition. Hence, this study aimed to determine the most appropriate dimensions of stainless steel wire and its extent, for achieving the physiologic mobility in primary dentition.

MATERIAL AND METHODS

This study was designed as an in vitro experiment by using a typodont model of primary dentition. The baseline mobility of primary maxillary incisors was calibrated to the physiologic mobility of natural primary incisors by using a Teflon tape wrapped around the roots of resin teeth. Splinting was done using a stainless steel wire of 0.2 mm (Group I), 0.3 mm (Group II), and 0.4 mm (Group III). These groups were subdivided (a, b, and c) on the basis of the extent of the splint, and pre splint mobility (Pre-PV) and post-splint mobility (Post-PV) were tested by Periotest M. The splint effect was calculated by subtracting Post-PVs and Pre-PVs.

RESULTS

The normal values of mobility in healthy human volunteers ranged from 10.5 to 13. The overall splint effect was higher in Group III irrespective of the extent of the splint, whereas it was found to be the lowest in Group I (b and c). The splint effect increased with the extent of the splint in all the groups. Among all the groups, the splint effect on the anchor teeth was observed to increase with the extent of the splint and the diameter of the wire.

CONCLUSION

The mobility of the injured and anchor teeth splinted with 0.2-mm stainless steel wire was similar to the pre-splint and physiologic mobility. The most favorable extension was one tooth adjacent to the injured tooth on each side for both 0.2- and 0.3-mm wires.

A new CAD/CAM tooth mobility simulating model for dental in vitro investigations

OBJECTIVES

To validate a new tooth mobility simulating in vitro model for biomechanical tests of dental appliances and restorations.

MATERIAL AND METHODS

Load-deflection curves for teeth in CAD/CAM models (n = 10/group, 6 teeth/model) of the anterior segment of a lower jaw with either low tooth mobility (LM) or high tooth mobility (HM) were recorded with a universal testing device and a Periotest device. All teeth were tested before and after different ageing protocols. Finally, vertical load capacity (Fmax) was tested in all teeth.

RESULTS

At F = 100 N load, vertical/horizontal tooth deflections before ageing were 80 ± 10 µm/400 ± 40 µm for LM models and 130 ± 20 µm/610 ± 100 µm for HM models. Periotest values were 1.6 ± 1.4 for LM models and 5.5 ± 1.5 for HM models. These values were within the range of physiological tooth mobility. No visible damage occurred during ageing and simulated ageing had no significant effect on tooth mobility. Fmax values were 494 ± 67 N (LM) and 388 ± 95 N (HM).

CONCLUSION

The model is practical, easy to manufacture and can reliably simulate tooth mobility. The model was also validated for long-term testing, so is suitable for investigating various dental appliances and restorations such as retainers, brackets, dental bridges or trauma splints.

CLINICAL RELEVANCE

Using this in-vitro model for high standardised investigations of various dental appliances and restorations can protect patients from unnecessary burdens in trials and practice.

Influence of preoperative degree of tooth loosening and thickness of wire on the rigidity of wire composite splint

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Fractured alveolar process displacement evaluation-Effect of the rigidity of wire-composite splints

BACKGROUNDS/AIMS

Traumatic dental injuries with bone fractures require rigid splinting. The degree of rigidity of the wire-composite splints can be challenging. The aim of this study was to evaluate the effect of the rigidity of different wire-composite splints on alveolar process displacement.

MATERIAL AND METHODS

A model was created using polystyrene resin to simulate the anterior maxilla, bovine incisors to simulate maxillary incisors, and polyether impression material to simulate the periodontal ligament. An alveolar process fracture was created, while maintaining the labial bone connection with the PDL. Four wire-composite splints (0.3, 0.6, 0.9, and 1.2 mm in diameter) were compared with models without splints and with no fracture (n = 5). The alveolar process displacement was measured (3 times per model/per splint type) at the fractured and adjacent central incisor regions using a deflectometer (Instron) under functional cycling and static loading (100 N). Data (μm) were analyzed using RM ANOVA, followed by Tukey's HSD test (α = 0.05).

RESULTS

The displacement at the region of the adjacent incisor was not influenced by the splint during static and cycling load (P > .05). The Tukey test demonstrated that the model without splints had significantly higher alveolar process displacement at the traumatized teeth than that of all other splint models (P < .001). Increasing the wire diameter from 0.3 mm to 0.9 mm significantly reduced the alveolar process displacement (P < .001). No difference was observed between the 0.9 mm (P = .123) and 1.2 mm (P = .219) wire-composite splints irrespective of the measured tooth regions.

CONCLUSIONS

The rigidity of the wire-composite splint significantly influenced the mobility of the fractured alveolar process. The use of at least 0.9 mm wire was effective in reducing the fractured alveolar process displacement to a level that was similar to the adjacent teeth.

Tooth Mobility Reproduction in Dental Material Research: A Scoping Review

Background:

Introducing tooth mobility simulation in laboratory studies can provide results with high accuracy and predictability.

Objectives:

This study aims to review in vitro methodologies replicating tooth mobility and provide a recommended approach for future laboratory models.

Methods:

Databases, such as PubMed, Cochrane Database of Systematic Review, BioMed Central and Chinese databases are searched, and twelve articles are included in the final review.

Results:

Simulation methods of tooth mobility involving socket enlargement, screw loosening, alveolar bone loss simulation and a combination approach are identified from the extracted data. The materials used in preparing artificial teeth, artificial sockets and periodontal ligament simulator are discussed with a focus on their limitations. The achieved degrees of mobility and the presence of the centre of rotation are also evaluated. A timeline of the review articles is constructed to understand the trend of the preferred methods in tooth mobility simulation.

Conclusion:

Future in vitro investigations can achieve clinical reliability, particularly for materials tested in the field of dental traumatology and periodontology, by recognising the importance of incorporating tooth mobility in laboratory studies. Improvised methods are proposed to ensure that potential laboratory models can resemble the actual oral environment.

Establishment of experimental models to evaluate the effectiveness of dental trauma splints

The purpose was to describe a novel simple experimental model of injured teeth for developing dental trauma splints (DTS), and to test various splints by combining use of this model and the Periotest^® device. Rubber O-rings and spring washers were used to simulate and modify injured tooth mobility. Splinting effects were assessed among three kinds of DTS, including a composite splint and two wire-composite splints (1: rectangular orthodontic wire 0.533×0.635 mm, 2: cobalt-chromium alloy wire Φ0.9 mm). The Periotest values were measured three times for each tooth before and after splint insertion. The splinting effect was defined as the change in tooth mobility. Splinting effects significantly increased in the order wire-composite splint 1<wire-composite splint 2<composite splint (p<0.05). This model system could evaluate the effects of DTS including the differences among various splint methods, which showed reasonable reproducibility of dental trauma situations depending on severity in clinical usage.