Effect of Low Intensity Laser Therapy (LILT) on MMP-9 expression in gingival crevicular fluid and rate of orthodontic tooth movement in patients undergoing canine retraction: A randomized controlled trial.

INTRODUCTION: Low Intensity Laser Therapy (LILT) has been shown to increase the rate of tooth movement. Since its use in orthodontics as a method of acceleration there has been a variety of views regarding its mode of action. MMP-9 is a known bone resorption factor studied in Bone remodelling. The aim of this study was to know the effect of LILT on rate of tooth movement and expression of MMP-9 in GCF. MATERIALS AND METHODS: Ten patients (3 males and 7 females) who required maxillary first premolar extraction for routine orthodontic treatment were recruited. The individual canine retraction was studied, and the side of the experimental canine was randomly selected. The laser regimen was followed on the 1st, 3rd, 5th, 7th, 14th and then 15th days consecutively. GCF was collected at baseline, 14th day, 3 months and at the end of canine retraction on experimental side and MMP-9 was estimated quantitatively using a standard ELISA kit. RESULTS: The average increase in rate of tooth movement on experimental side at 3 months was 44% and MMP-9 concentration was also high. At the end of canine retraction (4.5 months) in the experimental group the average rate increase was 38% with MMP-9 concentrations similar in both the experimental and control group. CONCLUSIONS: LILT increases the rate of tooth movement. LILT also has an effect of bio-stimulation as depicted by rise in MMP-9 concentrations in GCF. However, this bio-stimulatory effect is restricted to the initial part of the tooth movement.

The relationship between salivary insulin-like growth factor I and quantitative cervical maturational stages of skeletal maturity.

OBJECTIVE: Insulin-like growth factor (IGF-I) has been used as an indicator of growth hormone levels and hence can also be used as a marker of growth. The main objective of the study was to quantify salivary IGF-I levels and its secretion rate at different quantitative cervical maturation (QCVM) stages and evaluate a possible role for salivary IGF-I in evaluating skeletal growth. METHODS: Forty-five subjects (24 female, 21 male) between the ages of 7 and 23 years were included in the study. Each subject had personal information, a lateral cephalogram, and a parotid saliva sample collected on the same day. RESULTS: Salivary IGF-I levels and salivary secretion rates were lowest at QCVM skeletal stages previously associated with the acceleration phase of mandibular growth. Highest levels were found at the high velocity stage. After this there was gradual drop in salivary IGF-I levels and secretion rate at deceleration and completing velocity stages. Relatively high levels in the decelerating velocity stage may be an indication of residual skeletal growth. There was a negative correlation between patient age and levels of IGF-I and its secretion rate, once growth velocity decreased. CONCLUSIONS: Salivary IGF-I levels or its secretion rate can be used as an indicator of skeletal growth but longitudinal data are necessary to confirm salivary IGF-I as a marker for skeletal growth prediction and residual mandibular growth.

Efficacy of low-intensity laser therapy in reducing treatment time and orthodontic pain: a clinical investigation.

INTRODUCTION: The long duration of orthodontic treatment is a major concern for patients. A noninvasive method of accelerating tooth movement in a physiologic manner is needed. The aim of this study was to evaluate of the efficacy of low-intensity laser therapy in reducing orthodontic treatment duration and pain. METHODS: Twenty patients requiring extraction of first premolars were selected for this study. We used a randomly assigned incomplete block split-mouth design. Individual canine retraction by a nickel-titanium closed-coil spring was studied. The experimental side received infrared radiation from a semiconductor (aluminium gallium arsenide) diode laser with a wavelength of 810 nm. The laser regimen was applied on days 0, 3, 7, and 14 in the first month, and thereafter on every 15th day until complete canine retraction was achieved on the experimental side. Tooth movement was measured on progress models. Each patient's pain response was ranked according to a visual analog scale. RESULTS: An average increase of 30% in the rate of tooth movement was observed with the low-intensity laser therapy. Pain scores on the experimental sides were significantly lower compared with the control sides. CONCLUSIONS: Low-intensity laser therapy is a good option to reduce treatment duration and pain.

Static frictional force and surface roughness of various bracket and wire combinations.

INTRODUCTION: During sliding mechanics, frictional resistance is an important counterforce to orthodontic tooth movement, which must be controlled to allow application of light, continuous forces. We investigated the static frictional resistance between 3 modern orthodontic brackets-ceramic with gold-palladium slot, ceramic, and stainless steel-and 4 archwires (0.019 × 0.025-in)-stainless steel, nickel-titanium, titanium-molybdenum alloy (TMA), and low-friction colored TMA. METHODS: All tests were carried out in a dry state on a universal testing machine. Surface topography of bracket slots and archwires was studied by using a scanning electron microscope and quantified by using a surface roughness testing machine (profilometer). RESULTS: In the scanning electron microscope measurements, the smoothest surface was the ceramic gold-palladium bracket and stainless steel wire. The profilometer quantified the surface roughness, which also was lowest for the ceramic gold-palladium bracket and stainless steel wire. The ceramic bracket with the gold-palladium slot showed the least frictional values in all combinations and could be a promising alternative to solve the problem of friction. Frictional values for colored TMA were comparable with stainless steel wires and might be a good alternative during space closure in sliding mechanics. CONCLUSIONS: Ceramic with gold-palladium slot bracket and colored TMA archwire seem to be a good alternative to stainless steel in space closure with sliding mechanics.

Speech defect and orthodontics: a contemporary review.

In conjunction with the lips, tongue, and oropharynx, the teeth play an important role in the articulation of consonants via airflow obstruction and modification. Therefore, along with these articulators, any orthodontic therapy that changes their position may play a role in speech disorders. This paper examines the relevant studies and discusses the difficulties of scientific investigation in this area. The ability of patients to adapt their speech to compensate for most handicapping occlusion and facial deformities is recognized, but the mechanism for this adaptation remains incompletely understood. The overall conclusion is that while certain malocclusions show a relationship with speech defects, this does not appear to correlate with the severity of the condition. There is no direct cause-and-effect relationship. Similarly, no guarantees of improvement can be given to patients undergoing orthodontic or orthognathic correction of malocclusion.

Early management of skeletal open bite with spring-loaded and magnetic bite blocks.

The purpose of this study was to evaluate the effects of spring-loaded and magnetic bite blocks in growing individuals with skeletal open bites. The sample consisted of patients between 8 and 13 years of age randomly divided into two groups. One group was treated with spring-loaded bite blocks while the other received treatment with magnetic bite blocks. Further, a group matched for age, sex, and mandibular plane angle served as a control. The treatment effects were evaluated clinically and cephalometrically and by electromyographic (EMG) examination of the masseter and temporalis muscles after 8 months. Both appliances showed significantly (P<.05) favorable orthopedic effects. The spring-loaded bite blocks closed the existing open bite by 3.3 mm on average with a significant maxillary incisor extrusion and molar intrusion. Magnetic bite blocks produced an average of 4.9 mm of open bite closure with significant intrusion of the molars in both arches. Overall, both appliances significantly enhanced condylar growth, altered it to a more anterosuperior direction, and produced significant true forward mandibular rotation. Significant increases in masseter and temporalis muscle activity at rest and maximum clenching were noted in both groups, which could be a positive factor in retaining the achieved result. After 10 months of retention with passive bite blocks, cephalograms indicated only an insignificant relapse.