Microapical surgery management of root resorption in anterior teeth caused by dental trauma: case report

Root resorption (RR) is a common complication of traumatic dental injuries (TDIs), which could result in tooth loss and affect life in severe cases. The management of a traumatized tooth with RR remains a challenge for clinicians. In our presented cases, the impacted teeth had a history of trauma and underwent thorough non-surgical endodontic treatment; however, RR still occurred months later and could be observed through a periapical radiograph. Therefore, root canal therapy was performed under a dental microscope with a quick-setting calcium silicate cement to repair the RR site. After a long follow-up, the affected teeth showed almost complete healing of the periradicular tissues without sign of RR. This report demonstrates that external root absorption is typically a consequence of traumatized teeth. However, to date, there is still no effective method for its treatment. Here, we successfully applied microscopical surgery to the traumatized teeth experiencing root absorption and provided them with a new healing opportunity.

The Expression of MMP-2 on the Pressure Side During Tooth Movement

Objectives: To explore the effects of matrix metalloproteinase-2 (MMP-2) on the development of orthodontic root resorption in rats and to provide a theoretical basis for prevention and treatment of root resorption in clinical diagnosis.Methods: Thirty-five 6-8-week-old male SD rats were randomly divided into 7 groups, each with 5 rats weighing approximately 200 g±20 g. An orthodontic traction device was applied between the right first molar and the maxillary incisor in the experimental rats, and a mesial tractive force of 60 g was applied. Five rats were used for the control group without orthodontic applications. After 0, 1, 3, 5, 7, 14, and 21 days, the maxillae were abducted, and immunohistochemical analysis was performed. We used hematoxylin eosin staining to observe root resorption. The expression of MMP-2 was also assessed by immunohistochemical staining. SPSS17.0 statistical software was used to process the data.Results: Forcing 3 d was observed in the formation of bone resorption lacunae, which were confined to the cementum. After that, it becomes more serious. The most serious damage in 7 days. In 14 d, root absorption was relieved, and osteogenic cells aggregated at the root absorption site. Root resorption lacuna visible dentin repair phenomenon. With the extension of the force application time, the expression of MMP-2 was raised gradually, reached the peak at 7 d, and then gradually declined, 21d tends to be stable, but still stronger than controls.Conclusion: MMP-2 is involved in the metabolism of extracellular matrix in the process of root absorption.

Mercury Content on Mangrove Roots and Telescopium telescopium in Kao Bay, North Halmahera

The process of extracting gold using mercury (Hg) carried out by Nusa Halmahera Minerals industries (PT. NHM) as well as by the community of illegal gold mining or gold mining without a permit (PETI) that occurs in the mining area of ​​Halmahera Island can have a negative impact on the aquatic environment. This study aims to determine the mercury absorption in mangrove roots of Rhizopora sp and Telescopium telescopium at two different stations. Sampling of mangrove roots was repeated 3 times for each station. Differences in the accumulation of heavy metals Hg in the roots of Rhizophora sp were analyzed using the T-test. The study showed that the concentration of mercury in the roots of Rhizophora sp ranged from 0.016 – 0.026 mg/kg and there were differences in root absorption between Rhizopora sp at station 1 of the Tabobo River mangrove near the PETI disposal and station 2 at the mining industry waste disposal. The concentration of mercury in Telescopium telescopium ranged from 0.08 - 0.15 mg/kg. It is indicates that Telescopium telescopium in Kao Teluk has been contaminated with mercury but is still below the threshold of the quality standard that has been set.

Orthodontic Traction of Impacted Teeth with Modified Nance Appliance : Case Reports

Proper treatment of an impacted tooth is required as it causes functional and esthetic disharmony, as well as it can cause root absorption of adjacent teeth. Treatment options for impacted teeth include periodic observation, surgical exposure, orthodontic traction followed by surgical exposure, tooth transplantation, and extraction. Modified Nance appliance, used for orthodontic traction, is clinically useful because it does not require patient cooperation. Through orthodontic traction combined with surgical exposure of impacted maxillary incisors, canines, and molars using modified Nance appliance, adequate results can be obtained.

Root Morphology and Secretion of two subtropical tree species to NH4+-N and NO3–-N Deposition

Background: Both NH4+ and NO3– are capable of greatly influencing plants’ growth and biomass. However, the belowground responses of subtropical trees to either NH4+ or NO3– deposition remain poorly understood. Here, we discuss how these two forms of N deposition can affect root development, and experimentally analyzed how they could impact nitrogen and phosphorus absorption in two types (broadleaved with a fibrous root system vs. conifer with a tap root system) of subtropical tree species. Results: In a greenhouse in southern China, 1-year-old S. superba and P. massoniana seedlings grown on P-limited and P-normal soil were treated with NaNO3 and NH4Cl solutions of 0, 80, and 200 kg N ha–1 year–1, corresponding to the control, N80, and N200 groups, respectively. Root phenotype characteristics and metabolism ability were measured after 8 months of growth. The results showed that the root morphology and physiology variables differed significantly between the two species under different N and P treatments. Although S. superba had a larger quantity of roots than P. massoniana, both its root growth rate and root absorption were respectively lower and weaker. N addition differentially affected root growth and activity as follows: (1) NO3–-N80 and NH4+-N80 increased root growth and activity of the two species, but NH4+-N80 led to thicker roots in S. superba; (2) NO3–-N200 and NH4+-N200 had inhibitory effects on the roots of P. massoniana, for which NH4+-N200 led to thinner and longer roots and even the death of some roots; and (3) NH4+-N could promote metabolic activity in thicker roots (> 1.5 mm) and the NO3–-N was found to stimulate activity in thinner roots (0.5–1.5 mm) in the fibrous root system having a larger quantity of roots, namely S. superba. By contrast, NO3–-N and NH4+-N had an opposite influence upon functioning in the tap root system with a slender root, namely P. massoniana. Conclusion: We conclude P. massoniana has a much higher root absorption efficiency; however, nitrogen deposition is more beneficial to the root growth of S. superba.

Evaluation of mesotrione tolerance levels and [14C]mesotrione absorption and translocation in three fine fescue species

Fine fescues (Festuca spp.) are cool-season grasses used in low-maintenance turf areas. Mesotrione is a PRE and early-POST herbicide used during establishment of most cool-season turfgrasses, excluding fine fescues. Currently, efforts are being made to breed for increased tolerance to mesotrione in fine fescues to enhance weed control during establishment. This study was conducted to evaluate the association of foliar and root uptake of [14C]mesotrione with the tolerance of three lines each of Chewings fescue [Festuca rubra ssp. commutata Gaudin; syn. F. rubra ssp. fallax (Thuill.) Nyman], hard fescue [Festuca trachyphylla (Hack.) Hack.], and strong creeping red fescue (Festuca rubra L. ssp. rubra) lines. From a rate-titration experiment, the hierarchical rank of species for mesotrione tolerance from highest to lowest was: hard > Chewings > strong creeping red fescue. The hierarchical rank of species for foliar uptake from highest to lowest was: Chewings > strong creeping red > hard fescue. Translocation of foliar-absorbed 14C was not associated with differential tolerance levels of the three species. Root absorption was comparable among species, but differences between lines were detected within the species. The most susceptible lines of Chewings and strong creeping red fescue exhibited greater root uptake than lines with greater tolerance. Hard fescue translocated the least amount of root-absorbed radioactivity to shoots, while Chewings and strong creeping red fescues were comparable.