Introduction: Low level laser therapy (LLLT) also known as photobiomodulation, is a treatment that uses low-level lasers or light-emitting diodes (LEDs) to change cellular function and is a clinically well accepted tool in regenerative medicine and dentistry. Considering the variety of laser, exposure, cells and study types, the exact effects of low level laser therapy seems to be unclear. The aim of this study was to review the data published in the field of the effects of low level laser therapy on proliferation and differentiation of the cells contributing in bone regeneration.
Methods: To access relevant articles, an electronic search in PubMed was conducted from 2001 to April 2014. English language published papers on low level laser therapy were found using the selected keywords .The full texts of potentially suitable articles were obtained for final assessment according to the exclusion and inclusion criteria.
Results: 240 articles were found from 2001 to April 2014. Following the initial screening of titles and abstracts as well as the final screening of full texts, 22 articles completely fulfilled the inclusion criteria of this study. Wavelength used in LLLT irradiation varied between 600 to 1000 nm with an energy density of 0.04–60J/cm2 . Although almost all studies agreed on getting positive effects from LLLT, some had opposing results.
Conclusion: Low level laser with low-energy density range appears to exert a biostimulatory effect on bone tissue, enhance osteoblastic proliferation and differentiation on cell lines used in in vitro studies. Despite the fact that many researches have been recently done on the effects of LLLT on different cell lines, without knowing the precise mechanism and effects, we are not able to offer a clinical treatment protocol. This paper is a beginning to help further progress and extend practical use of LLLT in future.
low-level laser therapies; cell line; bone regenerations
Dentin is composed of many minerals and growth factors. Based on this composition, we studied its effect as a possible regenerative material for alveolar healing.
Materials and Methods
This study was conducted using four 2.5-year-old mongrel dogs (male; weight, 25 to 30 kg). The third mandibular premolars were carefully mobilized with a dental elevator and then removed using forceps. The crown portions of the extracted teeth were removed with cutters, and the root portions of the remaining teeth were collectively trimmed as closely as possible to 350 to 500 µm. Dentin and cementum (DC) chips harvested from the extracted teeth were soaked in blood and packed into the fresh sockets (autograft). Biopsies were performed at the ends of day 14 and day 56 following implantation. Data were expressed as mean±standard deviation and compared with t-test results.
The ratio of SA(bone) to total area of each probe was determined and was 170±16 µm2 for the control group and 71±14 µm2 for the DC group, a significant difference (P<0.05).
DC particulate grafts offered no improvement in bone regeneration in alveolar extraction sockets.
Dentin; Cementum; Tooth extraction; Healing
This article proposes a combined technique including bone grafting, connective tissue graft, and coronally advanced flap to create some space for simultaneous bone regrowth and root coverage.
A 23 year-old female was referred to our private clinic with a severe class II Miller recession and lack of attached gingiva. The suggested treatment plan comprised of root coverage combined with xenograft bone particles.
The grafted area healed well and full coverage was achieved at 12-month follow-up visit. Bone-added periodontal plastic surgery can be considered as a practical procedure for management of deep gingival recession without buccal bone plate.
Plastic surgery; Root coverage; Periodontal regeneration; Bone graft
This study aimed to assess the interdental bone level in premolar bitewing radiographs while retracting the cheeks.
Seventy-two horizontal bone defects were created on dried mandibles and maxillae. The distance from the bone level to the cement-enamel junction of premolars was detected by a modified digital caliper (considered the gold standard). The reliability of all radiographs was assessed by intraclass correlation coefficient (ICC), and the validity was compared to the gold standard using the analysis of variance test. P-values less than 0.05 were considered statistically significant.
This study showed that the reliability of radiographs without a cheek simulator and with 0.16 second exposure time was significantly higher than that of the two other groups (ICC=0.96 compared to 0.93 and 0.88, respectively). The results from the radiographs without a cheek simulator and with 0.16 second exposure time were more similar to the gold standard measures than those of the two other groups, although the difference was not statistically significant.
Retracting the buccal soft tissue plays an important role in increasing the accuracy of radiographs in detecting the interdental alveolar bone level and produces more accurate results than increasing the exposure time, although it does not have a significant role in reliability of results.
Alveolar bone loss; Bitewing radiography; Cheek
This study aimed to assess and compare the levels of interleukin-1beta (IL-1β) and interleukin-6 (IL-6) in the crevicular fluid around healthy implants, implants with peri-implantitis, and healthy teeth.
Materials and Methods
This study evaluated 16 dental implants in 8 patients (4 males and 4 females). These patients had at least one healthy implant and one implant with peri-implantitis next to healthy teeth. The crevicular fluid was collected using absorbent cones and transferred to the laboratory. Specimens were evaluated by ELISA for interleukin levels. Data were analyzed using repeated measures ANOVA and Bonferroni tests (P<0.05).
Levels of IL-1β in the crevicular fluid around implants with peri-implantitis were significantly higher than around healthy implants (P=0.002); the latter was significantly higher than around healthy teeth (P=0.015). A significant difference was found in the level of IL-6 in the crevicular fluid around implants with peri-implantitis and healthy implants (P=0.049) and also between implants with peri-implantitis and healthy teeth (P<0.001).
Within the limitations of this study, significant differences exist in the levels of IL-1β and IL-6 in the crevicular fluid of implants with peri-implantitis, healthy implants, and healthy teeth. More studies with larger sample sizes in different populations are necessary.
Dental implants; Peri-implantitis; Interleukin-1beta; Interleukin-6; Gingival crevicular fluid
Peri-implantitis and periodontitis are inflammatory and infectious diseases of implant and tooth-supporting tissues. Recently, the role of gene polymorphisms of immune response components in the relevant pathogenesis has been investigated. The present study was the first to evaluate the relationship between two known single nucleotide polymorphisms (SNPs) of the receptor activator of nuclear factor kappa-β (RANK) gene (rs3018362 and rs35211496) in chronic periodontitis and peri-implantitis patients in an Iranian population.
Eighty-one periodontally healthy patients, 38 patients with peri-implantitis, and 74 patients with chronic periodontitis were enrolled in this study. DNA was extracted from blood arm vein samples by using Miller's salting out technique according to the manufacturer's instructions given in the extraction kit. The concentration of DNA samples was measured using a spectrophotometer. The genetic polymorphisms of the RANK gene were evaluated using a competitive allele specific polymerase chain reaction (KBioscience allele specific PCR) technique. Differences in the frequencies of genotypes and alleles in the diseased and healthy groups were analyzed using chi-squared statistical tests (P<0.05).
Analysis of rs35211496 revealed statistically significant differences in the expression of the TT, TC, and CC genotypes among the three groups (P=0.00). No statistically significant difference was detected in this respect between the control group and the chronic periodontitis group. The expression of the GG, GA, and AA genotypes and allele frequencies (rs3018362) showed no statistically significant difference among the three groups (P=0.21).
The results of this study indicate that the CC genotype of the rs35211496 RANK gene polymorphism was significantly associated with peri-implantitis and may be considered a genetic determinant for peri-implantitis, but this needs to be confirmed by further studies in other populations.
Genetic polymorphism; Peri-implantitis; Periodontitis; Receptor activator of nuclear factor-kappa B
The present study was conducted to determine the reproducibility of peri-implant tissue assessment using the new implant success index (ISI) in comparison with the Misch classification.
Materials and Methods
In this descriptive study, 22 cases of peri-implant soft tissue with different conditions were selected, and color slides were prepared from them. The slides were shown to periodontists, maxillofacial surgeons, prosthodontists and general dentists, and these professionals were asked to score the images according to the Misch classification and ISI. The intra- and inter-observer reproducibility scores of the viewers were assessed and reported using kappa and weighted kappa (WK) tests.
Inter-observer reproducibility of the ISI technique between the prosthodontists-periodontists (WK=0.85), prosthodontists-maxillofacial surgeons (WK=0.86) and periodontists-maxillofacial surgeons (WK=0.9) was better than that between general dentists and other specialists. In the two groups of general dentists and maxillofacial surgeons, ISI was more reproducible than the Misch classification system (WK=0.99 versus WK non-calculable, WK=1 and WK=0.86). The intra-observer reproducibility of both methods was equally excellent among periodontists (WK=1). For prosthodontists, the WK was not calculable via any of the methods.
The intra-observer reproducibility of both the ISI and Misch classification techniques depends on the specialty and expertise of the clinician. Although ISI has more classes, it also has higher reproducibility than simpler classifications due to its ability to provide more detail.
Peri-implantitis; Classification; Reproducibility; Bone loss
This study aimed to assess the combined effect of dismantling before sterilization and aging on the accuracy (±10% of the target torque) of spring-style mechanical torque devices (S-S MTDs).
Twenty new S-SMTDs from two different manufacturers (Nobel Biocare and Straumann: 10 of each type) were selected and divided into two groups, namely, case (group A) and control (group B). For sterilization, 100 cycles of autoclaving were performed in 100 sequences. In each sequence, 10 repetitions of peak torque values were registered for aging. To measure and assess the output of each device, a Tohnichi torque gauge was used (P<0.05).
Before steam sterilization, all of the tested devices stayed within 10% of their target values. After 100 cycles of steam sterilization and aging with or without dismantling of the devices, the Nobel Biocare devices stayed within 10% of their target torque. In the Straumann devices, despite the significant difference between the peak torque and target torque values, the absolute error values stayed within 10% of their target torque.
Within the limitations of this study, there was no significant difference between the mean and absolute value of error between Nobel Biocare and Straumann S-S MTDs.
Dental implants; Safety; Sterilization; Torque
The purpose of this paper was to review the commercially available periodontal dressings, their physical and chemical properties, biocompatibility and therapeutic effects. Electronic search of scientific papers from 1956 to 2012 was carried out using PubMed, Scopus and Wiley InterScience search engines using the searched terms periodontal dressing, periodontal pack. Numerous in vitro and in vivo studies have evaluated various properties of periodontal dressings. Physical and chemical properties of dressings are directly related to their dimensional changes and adhesion properties. Their biocompatibility and therapeutic effect are among the other factors evaluated in the literature. Chlorhexidine is the most commonly used antibacterial agent in studies. In general, when comparing the advantages with the disadvantages, application of periodontal dressing seems to be beneficial. Numerous factors are involved in selection of an optimal dressing such as surgeon’s intention, required time for the dressing to remain on the surgery site and its dimensional changes.
Biocompatibility; Coe-Pak, cytotoxicity; periodontal dressing; therapeutic agent; wounds
There are numerous studies supporting the high success rate of dental implants used for reconstruction of missing teeth. However, complications like mucositis and peri-implantitis are increasingly reported. Placement of dental implants in partially edentulous patients is associated with the risk of peri-implant diseases, especially when an old or a new inflammatory lesion is present adjacent to the implant site. Although no consensus has been reached on the difference in prevalence of peri-implant mucositis and peri-implantitis between fully and partially edentulous patients, available data clearly show that the combination of periodontal lesion and peri-implantitis is a possible risk factor for further complications. Several classification systems have been suggested for determination of the severity of disease around dental implants. However, no classification has been proposed for combined biological complications around teeth and implants. This study reviews the possible pathologic communication routes between natural dentition and the implants installed adjacent to them. Furthermore, we introduce a new classification system for the peri-implant disease in association with natural teeth called “PIST”. This system was designed based on the origin of the defects in order to clarify the different pathological situations which can be detected around dental implant. Using this classification system can help improve diagnosis, comparison and subsequent selection of the best treatment option.
Classification; Peri-implantitis; Periodontal disease; Periapical Diseases
Background and aims. The aim of this study was to determine the stress patterns within an implant and the effect of different types of connections on load transfer.
Materials and methods. Three different types of implant-abutment connections were selected for this study. Sample A: 1.5-mm deep internal hex corresponding to a lead-in bevel; sample B: a tri-channel internal connection; and sample C: in-ternal Morse taper with 110 degrees of tapering and 6 anti-rotational grooves. Four types of loading conditions were simu-lated in a finite element model, with the maximum von Mises stress set as output variables.
Results. The maximum stress concentration at the inner surface of the fixtures was higher than the stress value in bone in all of the samples. Stress values in sample B were the lowest amongst all of the models. Any alterations in the amount and direction of the 100-N axial load resulted in an increase in fixture surfaces stress. Overall, the highest amount of stress (112 MPa) was detected in sample C at the inner surface of the fixture under a non-axial load of 300 N.
Conclusion. Stress concentration decreased when the internal surface area increased. Creating three or six stops in the internal surface of the fixtures resulted in a decrease in stress.
Biomechanics; dental implant/abutment; finite element; stress
Different techniques have been proposed for the treatment of gingival recession. The majority of current procedures use autogenous soft-tissue grafts, which are associated with morbidity at the donor sites. Acellular dermal matrix (ADM) Alloderm is an alternative donor material presented to reduce related morbidity and provide more volume of the donor tissue. This study aimed to evaluate the effectiveness of an ADM allograft for root coverage and to compare it with a connective tissue graft (CTG), when used with a double papillary flap.
Materials and Methods:
Sixteen patients with bilateral class I or II gingival recessions were selected. A total of 32 recessions were treated and randomly assigned into the test and contralateral recessions into the control group. In the control group, the exposed root surfaces were treated by the placement of a CTG in combination with a double papillary flap; and in the test group, an ADM allograft was used as a substitute for palatal donor tissue. Probing depth, clinical attachment level, width of keratinized tissue (KT), recession height and width were measured before, and after 2 weeks and 6 months of surgery.
There were no statistically significant differences between the test and control groups in terms of recession reduction, clinical attachment gain, and reduction in probing depth. The control group had a statistically significant increased area of KT after 6 months compared to the test group.
ADM allograft can be considered as a substitute for palatal donor tissue in root coverage procedure.
Acellular dermal matrix; connective tissue; esthetics; gingival recession/surgery; grafts
The present study aimed to measure root surface roughness in teeth with periodontitis by a profilometer following root planning with ultrasonic and hand instruments with and without erbium-doped yttrium aluminium garnet (Er:YAG) laser irradiation.
Sixty single-rooted maxillary and mandibular teeth, extracted because of periodontal disease, were collected. The crowns and apices of the roots were cut off using a diamond bur and water coolant. The specimens were mounted in an acrylic resin block such that a plain root surface was accessible. After primary evaluation and setting a baseline, the samples were divided into 4 groups. In group 1, the samples were root planned using a manual curette. The group 2 samples were prepared with an ultrasonic scaler. In group 3, after scaling with hand instrumentation, the roots were treated with a Smart 1240D plus Er:YAG laser and in group 4, the roots were prepared with ultrasonic scaler and subsequently treated with an Er:YAG laser. Root surface roughness was then measured by a profilometer (MahrSurf M300+RD18C system) under controlled laboratory conditions at a temperature of 25℃ and 41% humidity. The data were analyzed statistically using analysis of variance and a t-test (P<0.05).
Significant differences were detected in terms of surface roughness and surface distortion before and after treatment. The average reduction of the surface roughness after treatment in groups 1, 2, 3, and 4 was 1.89, 1.88, 1.40, and 1.52, respectively. These findings revealed no significant differences among the four groups.
An Er:YAG laser as an adjunct to traditional scaling and root planning reduces root surface roughness. However, the surface ultrastructure is more irregular than when using conventional methods.
Laser therapy; Periodontitis; Tooth; Ultrasonics
The effects of magnetostrictive and piezoelectric devices on tooth surfaces seem to differ with regard to the root surface roughness they produce. This study aimed to compare the results of scaling using magnetostrictive and piezoelectric devices on extracted teeth.
Forty-four human extracted teeth were assigned to four study groups (n=11). In two groups (C100 and C200), the teeth were scaled using a magnetostrictive device and two different lateral forces: 100 g and 200 g, respectively. In the other two groups (P100 and P200), the teeth were scaled with a piezoelectric device with 100 g and 200 g of lateral force, respectively. he teeth were scaled and the data on the duration of scaling and the amount of surface were collected and analyzed using the t-test.
The mean time needed for instrumentation for the piezoelectric and magnetostrictive devices was 50:54 and 41:10, respectively, but their difference was not statistically significant (P=0.171). For root surface roughness, we only found a statistically
significantly poorer result for the C200 group in comparison to the P200 group (P=0.033).
This study revealed that applying a piezoelectric scaler with 200 g of lateral force leaves smoother surfaces than a magnetostrictive device with the same lateral force.
Dental calculus; Dental scaling; Tooth extraction
A cursory review of the current socket preservation literatures well depicts the necessity of further esthetic considerations through the corrective procedures of the alveolar ridge upon and post extraction. A new technique has been described here is a rotational pedicle combined epithelialized and connective tissue graft (RPC graft) adjunct with immediate guided tissue regeneration (GBR) procedure.
We reviewed this technique through a case report and discuss it’s benefit in compare to other socket preservation procedures.
The main advantages of RPC graft would be summarized as follows: stable primary closure during bone remodeling, saving or crating sufficient vestibular depth, making adequate keratinized gingiva on the buccal surface, and being esthetically pleasant.
Bone; Dental implant; Esthetic
INTRODUCTION: The aim of this in vivo study was to determine the effect of demineralized bone matrix (DBM) on alveolar bone repair in type I diabetic rats.
MATERIALS AND METHODS: This study was carried out on 40 adult (8 weeks-old) albino rats with an average weight of 200-250 grams. The animals were divided into four groups (n=10) as follows: group 1 nondiabetic rats, group 2, 3 and 4 were diabetic rats, group 4 rats took one unit of insulin daily. Diabetes was induced by Alloxan Monohydrate through the tail veins of the rats in groups 2-4. Only group 4 received insulin NPH 1 unit daily. After 10 days, the upper right incisors of all samples were extracted and the socket was filled with DBM in groups 3 and 4. The animals were sacrificed at the end of week 1 and 2. The specimens were prepared and stained with H&E.
RESULTS: Histological results of group 4 displayed osteoblastic activity and bone formation with collagen fibers at the end of the first week and thick bone trabeculae formation in vicinity of DBM at the end of second week. In group 3, DBM showed some osteoinductivity at the end of the first week, but in some regions DBM particles were degraded by osteoclastic activity. Bone trabeculae formed with a dispersed and separate pattern at the end of second week. In group 2 hematoma and inflammation were dominant histological features at the end of first and second weeks; poor bone formation was detected in these two groups (2 and 3). In group 1, the results were as expected.
CONCLUSION: It seems demineralized bone matrix simulate osteoblastic activity.
Diabetes; Demineralized bone matrix; Microscopy; Tooth socket