Dental and Dentoalveolar Injuries in the Pediatric Patient

Dental and dentoalveolar injuries are common in the pediatric population. Management is predicated on the type of tooth injured (primary or permanent), extent of injury, the dental and behavioral age of the patient, and ability of the patient to tolerate treatment. Although many dental injuries occur in isolation, a systematic evaluation of the patient is mandatory to confirm the absence of basal bone fractures of the maxilla or mandible, traumatic brain injury, cervical spine injury, and/or facial soft tissue injury. Long-term follow-up is paramount to achieving a functional occlusion and optimal dental health following injury.

Accuracy of optical interocclusal registration using an intraoral scanner

PURPOSE

This study aimed to clarify the effect of occlusal force on appropriate optical interocclusal registration in clinical practice, considering periodontal ligament and jawbone deformation.

METHODS

Forty participants with natural, healthy dentition were enrolled (19 men and 21 women; mean age, 27.7 ± 2.0 years). A TRIOS3 intraoral scanner was used to scan the right lateral first premolar to the second molar areas of the upper and lower jaws. During scanning for interocclusal registration, participants were instructed to "bite normally," "bite lightly," and "bite strongly" to obtain data for the three occlusal patterns. The standard triangulated language (STL) data for each occlusion condition were superimposed using the appropriate software, following which the tooth displacement was calculated. The conventional method was also used to record the occlusal contact area for a silicone model using a dental contact analyzer.

RESULTS

Tooth displacement was significantly lower for the strong-bite condition than for the weak-bite condition (0.018 mm vs. 0.028 mm, P<0.05). As the occlusal force increased, the occlusal contact area also increased, and significant differences were observed among the different occlusal conditions (P<0.05).

CONCLUSIONS

Occlusal contact area changed depending on the bite force when using the silicone impression or optical intraoral scanning methods. Moreover, using optical impression methods in "strong bite force" may reduce the deviation and allow for stable interocclusal registration.

Measurement of tooth displacement

The periodontium is a biological structure that supports the tooth in the jaw and behave as a developmental, biological, and functional unit. Teeth may be considered to be 'suspended' in their tooth sockets which provides teeth the ability to move in response to an applied load. In terms of the protection the suspension effect of the periodontal ligament may offer dental restorations, movement in an axial direction is of interest. No device or system to measure this movement is readily available, thus a novel approach had to be developed to address the questions of this research. The device developed allowed images to be taken of the participants teeth before, during and after a participant bit down on the tooth and used to measure the displacement of the tooth in image processing software. Average maximum tooth displacement from all participants of 73.8 μm (sd = 22.5 μm) were recorded. Longer application time of bite force was associated with greater cumulative tooth displacement, for a given level of force, and female participants experienced approximately 2 μm more displacement per Newton than males. The device and methods utilised in this study has shown good potential as a measurement protocol for measurement of vertical tooth movements in vivo. The response to load the teeth in this study has shown, highlighted the visco-elastic properties of the periodontal ligament and the amount of movement recorded supports the protection that controlled tooth movement offers teeth.

Biomechanical properties of periodontal tissues in non-periodontitis and periodontitis patients assessed with an intraoral computerized electronic measurement device

OBJECTIVE

To identify tooth mobility (TM) by time-dependent tooth displacement using an electronic intra-oral loading device (ILD) in periodontally healthy and periodontally compromised patients.

MATERIALS AND METHODS

Twenty-eight untreated periodontitis and 20 periodontally healthy patients [25 female and 26 male; ages: 20-81 years], contributing with 68 teeth (periodontitis: n_teeth = 28; non-periodontitis: n_teeth = 40), participated in the study. TM was measured in vivo by displacing central or lateral incisors to a maximum of 0.2 mm orally over durations of 0.5 s, 1 s, and 10 s with the ILD. The maximum force (Fmax) was extracted from the measured force/deflection curves for every single measurement.

RESULTS

Differences in TM-ILD values were found for periodontitis as compared to non-periodontitis patients derived from the same loading durations (differences of 3.9 (0.5 s), 3.1 (1 s), 2.8 (10 s), (95% CI for 0.5 s (1.2-6.7), p = 0.024; 1 s (1.4-6.0), p = 0.067; 10 s (0.2-5.3), p = 0.001), rejecting the null hypothesis of no difference (T-test) for durations of 0.5 and 10 s. There was a significant correlation of TM-ILD (Fmax) with BOP at 0.5 s (- 0.52) and with attachment loss at all time durations (- 0.47 at 0.5 s; - 0.57 at 1 s; - 0.47 at 10 s).

CONCLUSIONS

This clinical investigation could demonstrate that time-dependent tooth displacements using a new computerized electronic device were associated with attachment loss and bleeding on probing.

CLINICAL RELEVANCE

ILD can improve the monitoring of tooth mobility, as TM-ILD values reflect qualitative (inflammatory status interpreted by BOP) and quantitative parameters (interpreted as the amount of CAL loss) of periodontal disease.

An extremely rare case of a displaced third molar into the infratemporal fossa associated with a textiloma

BACKGROUND

Third molar extraction is one of the most common procedures performed by oral surgeons, however with rare complications. The accidental displacement of a maxillary third molar into the infratemporal fossa (ITF) is a rare complication that can occur even with experienced surgeons.

CASE PRESENTATION

We describe the case of a 17-year-old patient whose right upper third molar was accidentally pushed to the ITF associated with a cellulitis and the late discovery of a textiloma (a surgical gauze).

CONCLUSIONS

Extraction of third molars is a safe surgical procedure when performed in appropriate conditions. The diagnosis of textiloma following a maxillo-facial surgery is extremely rare. It is important to take into account this possibility in order to avoid delaying treatment when it occurs.

Evaluation of adjacent tooth displacement in the posterior implant restoration with proximal contact loss by superimposition of digital models

PURPOSE

This study was conducted to investigate patterns of adjacent tooth displacement in the posterior implant with interproximal contact loss (ICL) by 3-D digital superimposition method.

MATERIALS AND METHODS

Posterior partially edentulous patients, restored with implant fixed partial prostheses before 2011 and suffered from food impaction of ICL between 2009 and 2011, were included. Two dental casts, at the time of delivery and at the time of food impaction in a same patient, was converted into 3-D digital models through scanning and superimposition was performed to assess chronologic changes of the dentition. Directions of tooth displacement were evaluated and the amount of ICL was calculated. Correlations between the amount of ICL and elapsed time, or between the amount of ICL and age after function, were assessed at a significance level of P<.05.

RESULTS

A total number of 13 patients (8 males, 5 females) with a mean age of 65.76 ± 9.94 years and 17 areas (4 maxillae, 13 mandibles) were included in this retrospective study. Teeth adjacent to the implant restoration showed complex displacements but characteristic tendency according to the location of the arch. The mean amount of ICL was 0.33 ± 0.14 mm. Elapsed time from function to ICL was 61.47 ± 31.27 months. There were no significant differences between the amount of ICL and elapsed time, or age (P>.05).

CONCLUSION

Natural teeth showed various directional movements to result in occlusal change in the arch. The 3-D superimposition of chronologic digital models was a helpful method to analyze the changes of dentition and individual tooth displacement adjacent to implant restoration.

In-vitro investigation of the mechanical friction properties of a computer-aided design and computer-aided manufacturing lingual bracket system under diverse tooth displacement condition

Objective

The purpose of this study was to compare the static (SFF) and kinetic frictional forces (KFF) of a computer-aided design and computer-aided manufacturing lingual bracket (CAD/CAM-LB) with those of conventional LB (Con-LB) and Con-LB with narrow bracket width (Con-LB-NBW) under 3 tooth displacement conditions.

Methods

The samples were divided into 9 groups according to combinations of 3 LB types (CAD/CAM-LB [Incognito], Con-LB [7th Generation, 7G], and Con-LB-NBW [STb]) with 3 displacement conditions (no displacement [control], maxillary right lateral incisor with 1-mm palatal displacement [MXLI-PD], and maxillary right canine with 1-mm gingival displacement [MXC-GD]; n = 6/group). While drawing a 0.016-inch copper or super-elastic nickel-titanium archwire with 0.5 mm/min for 5 minutes in a chamber maintained at 36.5℃, SFF and KFF were measured. The Kruskal-Wallis method with Bonferroni correction was performed.

Results

The Incognito group demonstrated the highest SFF, followed by the 7G and STb groups ([STb-control, STb-MXLI-PD, Stb-MXC-GD] < [7G-MXC-GD, 7G-MXLI-PD, 7G-control] < [Incognito-MXLI-PD, Incognito-control, Incognito-MXC-GD]; p < 0.001). However, there were no significant differences in SFF among the 3 displacement conditions within each bracket group. Within each displacement condition, the Incognito group demonstrated the highest KFF, followed by the 7G and STb groups ([STb-control, STb-MXLI-PD] < Stb-MXC-GD < 7G-MXLI-PD < [7G-control, 7G-MXC-GD] < [7G-MXC-GD, Incognito-MXLI-PD, Incognito-control] < [Incognito-control, Incognito-MXC-GD]; p < 0.001). MXC-GD exhibited higher KFFs than MXLI-PD in the same bracket group.

Conclusions

The slot design and ligation method of the CAD/CAM-LB system should be modified to reduce SFF and KFF during the leveling/alignment stage.

Management of upper and lower molars that are displaced into the neighbouring spaces

Our aim was to describe our experience of retrieval of accidental displacements of upper and lower molars into neighbouring anatomical spaces. Thirteen patients were evaluated retrospectively in terms of age, sex, affected side, jaw (mandible or maxilla), surgeon's experience, whether the extracted teeth had erupted, which portion of the tooth or teeth was displaced, the anatomical space into which the fragment was displaced, postoperative complaints, timing of the retrieval, type of anaesthesia, and surgical approach. There were no significant differences in sex, affected side, which part of the tooth was displaced, whether the extracted teeth had erupted, type of anaesthesia, or timing of retrieval. We conclude that this condition should be treated, although follow-up alone may be an option. The intraoral lingual pouch approach for complications of mandibular third molars and the intraoral Caldwell-Luc operation for those in the maxilla could be successful options for retrieval.

Frictional property comparisons of conventional and self-ligating lingual brackets according to tooth displacement during initial leveling and alignment: an in vitro mechanical study

Objective

We evaluated the effects of tooth displacement on frictional force when conventional ligating lingual brackets (CL-LBs), CL-LBs with a narrow bracket width, and self-ligating lingual brackets (SL-LBs) were used with initial leveling and alignment wires.

Methods

CL-LBs (7th Generation), CL-LBs with a narrow bracket width (STb), and SL-LBs (In-Ovation L) were tested under three tooth displacement conditions: no displacement (control); a 2-mm palatal displacement (PD) of the maxillary right lateral incisor (MXLI); and a 2-mm gingival displacement (GD) of the maxillary right canine (MXC) (nine groups, n = 7 per group). A stereolithographic typodont system and artificial saliva were used. Static and kinetic frictional forces (SFF and KFF, respectively) were measured while drawing a 0.013-inch copper-nickel-titanium archwire through brackets at 0.5 mm/min for 5 minutes at 36.5℃.

Results

The In-Ovation L exhibited lower SFF under control conditions and lower KFF under all displacement conditions than the 7th Generation and STb (all p < 0.001). No significant difference in SFF existed between the In-Ovation L and STb for a 2-mm GD of the MXC and 2-mm PD of the MXLI. A 2-mm GD of the MXC produced higher SFF and KFF than a 2-mm PD of the MXLI in all brackets (all p < 0.001).

Conclusions

CL-LBs with narrow bracket widths exhibited higher KFF than SL-LBs under tooth displacement conditions. CL-LBs and ligation methods should be developed to produce SFF and KFF as low as those in SL-LBs during the initial and leveling stage.

Teeth movement in denture and implant-supported prosthesis influenced by microwave flask systems

BACKGROUND/AIMS

This study evaluated the teeth movement in maxillary dentures and mandibular implantsupported prostheses processed by microwave flasks.

METHODS

A model mounted on articulator was used to manufacture Co-Cr frameworks. Pins were placed for measurements on the incisal edge of upper and lower central incisors (I), buccal cusp of first upper and lower premolars (PM), and mesiobuccal cusps of upper and lower second molars (M). Distances I-I (incisor to incisor), PM-PM (premolar to premolar), M-M (molar to molar), RI-RM (right incisor to right molar), and LI-LM (left incisor to left molar) were measured before and after processing using a microscope (0.0005 mm). Vertical misfit between abutment and implant platform was evaluated for regions A (left distal implant), B (left median implant), C (medial implant), D (right median implant), and E (right distal implant) in predetermined labial and lingual sites. Prostheses were divided into groups G1 - conventional flask, and G2 - experimental HH flask. Acrylic resin was microwaved at 1400 W (30% for 3 min, 0% for 3 min, and 60% for 3 min). Horizontal teeth displacement and vertical misfit between abutment and implant platform were considered before and after procedures. Data were submitted to three-way ANOVA and Tukey's test (α = 0.05).

RESULTS

Except for M-M distance, the teeth showed displacements without statistical difference for prosthesis and flask factors. There was no significant difference for vertical misfit values for both flasks.

CONCLUSION

Diferente flasks did not cause significant changes in the teeth displacement, except for M-M. Vertical misfit values were not influenced by the flasks.