Structure Of Cementum Research Articles

Does periodontal ligament removal using natural proteolytic enzymes alter the surface structure and microhardness of cementum of avulsed tooth? An in vitro analysis

Introduction: Surface treatment of avulsed tooth must be directed towards the debridement of necrotic periodontal fibers while having no effect on the cementum microhardness. The role of proteolytic enzymes on the periodontal ligament (PDL) surface and hardness of cementum has not been investigated in the literature. Aim: The present study aimed to evaluate the effect of 5.25% sodium hypochlorite (NaOCl), 10% bromelain, 10% papain and 10% panzyme on root surface topography and microhardness of avulsed teeth. Materials and Methods: Forty healthy premolars were freshly extracted and randomly allocated into five treatment groups based on the surface agent employed; Group 1: 50 ml saline, Group 2:20 ml of 5.25% NaOCl, Group 3: 20 ml of 10% bromelain enzyme, Group 4: 20 ml of 10% papain enzyme, and Group 5: 20 ml of 10% mixed panzyme enzyme. The specimens were then subjected to confocal laser scanning microscopy and scanning electron microscopic examination. Supplemental set of freshly extracted forty premolars were decoronated longitudinally and one-half from each specimen was submitted for Vickers microhardness testing before and after application of the above-mentioned agents. Statistical Analysis: Intragroup comparison of mean percentage hardness reduction was assessed using paired t-test. Results: Treatment with NaOCl led to complete removal of PDL fibers with the presence of cracks and crazes on the root surface along with a significant reduction in microhardness. Bromelain and papain revealed regular and even distribution, while few PDL fibers were evident with papain. Panzyme revealed a shiny surface with minute cracks and a significant reduction in microhardness. Conclusion: Ten percentage bromelain for 10 min was effective in the removal of necrotic PDL fibers and preserved the cementum integrity better.

A robust, semi-automated approach for counting cementum increments imaged with synchrotron X-ray computed tomography.

Cementum, the tissue attaching mammal tooth roots to the periodontal ligament, grows appositionally throughout life, displaying a series of circum-annual incremental features. These have been studied for decades as a direct record of chronological lifespan. The majority of previous studies on cementum have used traditional thin-section histological methods to image and analyse increments. However, several caveats have been raised in terms of studying cementum increments in thin-sections. Firstly, the limited number of thin-sections and the two-dimensional perspective they impart provide an incomplete interpretation of cementum structure, and studies often struggle or fail to overcome complications in increment patterns that complicate or inhibit increment counting. Increments have been repeatedly shown to both split and coalesce, creating accessory increments that can bias increment counts. Secondly, identification and counting of cementum increments using human vision is subjective, and it has led to inaccurate readings in several experiments studying individuals of known age. Here, we have attempted to optimise a recently introduced imaging modality for cementum imaging; X-ray propagation-based phase-contrast imaging (PPCI). X-ray PPCI was performed for a sample of rhesus macaque (Macaca mulatta) lower first molars (n = 10) from a laboratory population of known age. PPCI allowed the qualitative identification of primary/annual versus intermittent secondary increments formed by splitting/coalescence. A new method for semi-automatic increment counting was then integrated into a purpose-built software package for studying cementum increments, to count increments in regions with minimal complications. Qualitative comparison with data from conventional cementochronology, based on histological examination of tissue thin-sections, confirmed that X-ray PPCI reliably and non-destructively records cementum increments (given the appropriate preparation of specimens prior to X-ray imaging). Validation of the increment counting algorithm suggests that it is robust and provides accurate estimates of increment counts. In summary, we show that our new increment counting method has the potential to overcome caveats of conventional cementochronology approaches, when used to analyse three-dimensional images provided by X-ray PPCI.

A Cross-Sectional Cohort Study of the Effects of FGF23 Deficiency and Hyperphosphatemia on Dental Structures in Hyperphosphatemic Familial Tumoral Calcinosis.

ABSTRACTHyperphosphatemic familial tumoral calcinosis (HFTC) is a rare autosomal recessive disorder caused by mutations in FGF23, GALNT3, KLOTHO, or FGF23 autoantibodies. Prominent features include high blood phosphate and calcific masses, usually adjacent to large joints. Dental defects have been reported, but not systematically described. Seventeen patients with HFTC followed at the National Institutes of Health underwent detailed clinical, biochemical, molecular, and dental analyses. Studies of teeth included intraoral photos and radiographs, high‐resolution μCT, histology, and scanning electron microscopy (SEM). A scoring system was developed to assess the severity of tooth phenotype. Pulp calcification was found in 13 of 14 evaluable patients. Short roots and midroot bulges with apical thinning were present in 12 of 13 patients. Premolars were most severely affected. μCT analyses of five HFTC teeth revealed that pulp density increased sevenfold, whereas the pulp volume decreased sevenfold in permanent HFTC teeth compared with age‐ and tooth‐matched control teeth. Histology revealed loss of the polarized odontoblast cell layer and an obliterated pulp cavity that was filled with calcified material. The SEM showed altered pulp and cementum structures, without differences in enamel or dentin structures, when compared with control teeth. This study defines the spectrum and confirms the high penetrance of dental features in HFTC. The phenotypes appear to be independent of genetic/molecular etiology, suggesting hyperphosphatemia or FGF23 deficiency may be the pathomechanistic driver, with prominent effects on root and pulp structures, consistent with a role of phosphate and/or FGF23 in tooth development. Given the early appearance and high penetrance, cognizance of HFTC‐related features may allow for earlier diagnosis and treatment. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

Root cementum ultrastructure in healthy and periodontally diseased teeth

Relevance. Investigation of the root cementum ultrastructure in chronic generalized periodontitis is still relevant as changes in structure and composition of root cementum play a significant role in successful periodontal regeneration. Am is to study changes in the root cementum ultrastructure in patients with chronic generalized periodontitis.Materials and methods. Scanning electron microscopy (SEM) was used to study the cementum surface of 9 teeth extracted due to severe chronic generalized periodontitis and 3 teeth with a clinically healthy periodontium extracted for orthodontic reasons. 3D visualization of the received SEM images was performed.Results. The cementum of periodontally healthy teeth appeared homogeneous and regular,was covered in periodontal fibers and had a pebble-like or dome-shaped surface. In chronic periodontitis patients, the cementum surface was mostly irregular with multiple defects of various depth, areas of completely destroyed cementum, exposed dentinal tubules and a complete absence of periodontal fibers.Conclusion. Loss of periodontal attachment and root cementum exposure to microbial biofilm may result in irreversible structural changes of the surface which may affect the regeneration of clinical attachment.

Synchrotron radiation-based X-ray tomography reveals life history in primate cementum incrementation.

Cementum is a mineralized dental tissue common to mammals that grows throughout life, following a seasonally appositional rhythm. Each year, one thick translucent increment and one thin opaque increment is deposited, offering a near-complete record of an animal's life history. Male and female mammals exhibit significant differences in oral health, due to the contrasting effects of female versus male sex hormones. Oestrogen and progesterone have a range of negative effects on oral health that extends to the periodontium and cementum growth interface. Here, we use synchrotron radiation-based X-ray tomography to image the cementum of a sample of rhesus macaque (Macaca mulatta) teeth from individuals of known life history. We found that increased breeding history in females corresponds with increased increment tortuosity and less organized cementum structure, when compared to male and juvenile cementum. We quantified structural differences by measuring the greyscale 'texture' of cementum and comparing results using principal components analysis. Adult females and males occupy discrete regions of texture space with no overlap. Females with known pregnancy records also have significantly different cementum when compared with non-breeding and juvenile females. We conclude that several aspects of cementum structure and texture may reflect differences in sexual life history in primates.

Age estimation and growth layer patterns in teeth of crabeater seals: A comparison of techniques

AbstractAge estimation of marine mammals provides important information about ecological and life history parameters. Counting growth layer groups (GLGs) in the dentine and cementum of teeth is the most common technique for age estimation in pinnipeds. In this study, we used acid‐etched canines (n = 38) and decalcified stained postcanine sections (n = 40) to calibrate readings in mummified crabeater seals (Lobodon carcinophaga). A subsample of this group received a prior cleaning treatment of boiling the teeth with hydrogen peroxide (H2O2). Ages ranged from 0 to 31 years. Dentine from canines and cementum from postcanines showed higher estimated ages (maximum 31 years) than dentine from postcanines (maximum 24 years), mainly in those teeth that did not receive prior treatment. Boiling with H2O2 has shown to affect cementum structure and, thus, results in underestimated ages, but dentine did not seem to be affected. The results presented here showed that ages can be estimated for the crabeater seal regardless of which tooth/tissue or method is used, at least for seals <13 years old. However, nontreated, stained thin sections of postcanine teeth are recommended because more reliable age estimations in older crabeater seals are obtained.

The Construction of Biomimetic Cementum Through a Combination of Bioskiving and Fluorine-Containing Biomineralization.

Despite tremendous attention is given to the construction of biomimetic cementum for regeneration of tooth cementum, the lack of recapitulating the composition and hierarchical structure of cementum often leads to the poor performance of constructed materials. How to highly mimic the sophisticated composition and hierarchy of cementum remains a longstanding challenge in constructing the biomimetic cementum. Inspired by cementum formation process, a novel construction approach via a combination of bioskiving and fluorine-containing biomineralization is developed in this study. The alternative collagen lamellae (ACL) that can highly mimic the rotated plywood structure of cementum collagen matrix is fabricated via bioskiving. Followed by biomineralization in the amorphous calcium phosphate (ACP) solution with different concentration of fluorine, a series of biomimetic cementum is constructed. Screened by physicochemical characterization, the biomimetic cementum with the composition and hierarchical structure highly similar to human cementum is selected. Through in vitro biological assay, this biomimetic cementum is proven to significantly promote the adhesion, proliferation, and cementogenic differentiation of periodontal ligament cells (PDLCs). Furthermore, in vivo study demonstrates that biomimetic cementum could induce cementogenesis. This biomimetic cementum constructed via combinatory application of bioskiving and fluorine-containing biomineralization stands as a promising candidate for achieving cementum regeneration.

Microanalysis of Root Cementum in Patients with Rapidly ProgressivePeriodontitis

Objective: The objective of this study was to evaluate the microanalysis of various elements, and assess the surface characteristics of progressive periodontally diseased roots in comparison to sound root surface. Materials and Methods: 50 teeth were collected, 25 teeth from patients have progressive periodontitis, and 25 teeth from healthy patients. Measurements of probing depth and clinical attachment loss were taken prior to extractions. After the horizontal fracturing process of root specimens, healthy and diseased cementum layers of roots were evaluated by scanning electron microscopy (SEM) and energy dispersive X ray analysis (DXA). SEM and DXA. The collected data were statistically evaluated using t-test. The level of significance was set at p<0.001. Results: The results of this study showed a significant decrease in the calcium and phosphate contents along the entire cementum of root teeth of the progressive periodontitis and a significant increase in the magnesium and sulphur of the same root teeth in comparison to the control group. In addition, there were remarkable destructions of root cementum, crack lines and deep cavities reaching to the underlying dentin. Conclusion: In conclusion, the alteration in cementum structures and composition due to progressive periodontitis might have an important implication on periodontal therapy. The influence of alteration of cementum composition and structure on periodontal regeneration warrants further exploration.

New Insights on the Composition and the Structure of the Acellular Extrinsic Fiber Cementum by Raman Analysis.

Acellular extrinsic fiber cementum is a mineralized tissue that covers the cervical half of the tooth root surface. It contains mainly extrinsic or Sharpey’s fibers that run perpendicular to the root surface to anchor the tooth via the periodontal ligament. Acellular cementum is continuously and slowly produced throughout life and exhibits an alternating bright and dark pattern under light microscopy. However, although a better understanding of the structural background of acellular cementum is relevant to many fields, such as cementochronology, periodontology and tissue engineering, acellular cementum remains rarely studied and poorly understood. In this work, we studied the acellular cementum at the incremental line scale of five human mandibular canines using polarized Raman spectroscopy. We provided Raman imaging analysis and polarized acquisitions as a function of the angular orientation of the sample. The results showed that mineral crystals were always parallel to collagen fibrils, and at a larger scale, we proposed an organizational model in which we found radial collagen fibers, “orthogonal” to the cementum surface, and “non-orthogonal” fibers, which consist of branching and bending radial fibers. Concerning the alternating pattern, we observed that the dark lines corresponded to smaller, more mineralized and probably more organized bands, which is consistent with the zoological assumption that incremental lines are produced during a winter rest period of acellular cementum growth.

Cementum structure in Beluga whale teeth.

Cementum is an important tooth tissue to which the periodontal ligaments attach and consists primarily of carbonated apatite mineral and collagen. In optical microscopy of cementum thin sections, light/dark bands are formed annually, and age at death is determined by counting these bands. We employ synchrotron X-ray diffraction and X-ray fluorescence mapping to show the bands in Beluga whale cementum result from differences in mineral content and not from differences in collagen orientation as was concluded by others. Variation in Zn fluorescent intensity was found to be very sensitive indicator of changing biomineralization and suggest that Zn plays an important role this process.

Microscopic Differences in Cementum Structure and Mineral Composition of Teeth Extracted from Patients with Gingivitis, Chronic Periodontitis and Aggressive Periodontitis. A Preliminary Comparative Study

Background: During the progression of periodontal diseases, cementum undergoes alterations in its structure and mineral composition. Aim: To detect different alterations in structure and mineral composition of cementum according to different periodontal statuses. Subjects and Methods: A true experimental study carried out among six extracted human teeth (One gingivitis of badly decayed tooth (used as control), two chronic periodontitis and three aggressive periodontitis (teeth were extracted due to severe bone loss and mobility). Specimens were taken from different parts of the cementum of the extracted teeth. Each specimen was put in one millilitre of sodium hypochlorite 10 % concentration for 24 hours, then dehydrated by 100% alcohol for half an hour and cementum structures was examined under Scanning Electron Microscope. Student t-test was used to determine the difference between the groups with the level of significance set at P value ≤0.05. Results: There is difference in structure and minerals components of cementum between the specimens of gingivitis, chronic and aggressive periodontitis. Chronic periodontitis has higher amount of minerals with cracks on cementum. Aggressive periodontitis has hypoplasia in cementum, cracks and there is unequal distribution of phosphate and calcium on cemental surface. Conclusion: Different diseases in the periodontium can cause different changes in cementum structure and minerals composition.

Microanalysis of Root Cementum in Patients with Aggressive Periodontitis

The purpose of this study was to evaluate the microanalysis of various elements, and assess the surface characteristics of aggressive periodontally diseased roots in comparison to sound root surface. Fifty teeth were collected: 25 from patients with aggressive periodontitis, and 25 teeth from healthy patients. Measurements of probing depth and clinical attachment loss were taken prior to extractions. Healthy and diseased root cementum were evaluated by scanning electron microscopy and energy dispersive X-ray spectroscopy. The collected data were statistically evaluated using t-test. The level of significance was set at p &lt; 0.001. The results of this study showed a significant decrease in the calcium and phosphate contents along the entire root cementum of the aggressive periodontitis and a significant increase in the magnesium and sulphur of the same root in comparison to the control group. In addition, there were remarkable destructions of cementum, crack lines and deep cavities reaching to the underlying dentin. In conclusion, the alteration in cementum structures and composition due to aggressive periodontitis might have an important implication on periodontal therapy. The influence of alteration of cementum.

EFFECTS OF LASER TREATMENT ON INTRACANAL DENTINE AND CEMENTUM AT THE ROOT APEX

Laser irradiation during root canal treatment is efficient but in order to prevent irreversible thermal damage to dentine, cementum and other periapical structures continuous water cooling is required. The aim of this study was to ultrastructurally analyze the surface of intracanal dentine and cementum at the root apex after Er:YAG laser irradiation with and without sterile saline solution irrigation. The study involved 70 intact maxillary and mandibular single-rooted and tworooted human teeth, divided into two experimental groups and one control group. In all teeth access cavity was created. For root canal irradiation, Er:YAG laser with the wavelength of 2940 nm, energy output of 140 mJ per pulse, pulse duration of 125-160 ms, pulse repetition rate of 10 Hz and power of 15 W was used. Total irradiation time for each root canal was 10 seconds. The ultrastructural analysis of intracanal dentine and the cementum of the root apex was done by using scanning electron microscope (JEOL JSM-5300 Tokyo Japan). Intracanal Er:YAG laser irradiation without water cooling showed melted circumpulpal dentine with large cracks in it, whereas cementum at the root apex was thermally modified in the form of plates and cracks. Intracanal Er:YAG laser irradiation with continuous water cooling resulted in clean intracanal dentine surface without morphological changes of the cementum. The canal system irradiation is acceptable and possible only when using constant water cooling; otherwise, irreversible thermal damage to intracanal dentine and cementum at the root apex occur.

Histological review of the human cellular cementum with special reference to an alternating lamellar pattern

Cementum is mineralized tissue with collagen fibrils as its major organic component, and it can be roughly classified into acellular and cellular cementum. The latter generally consists of a stack of cellular intrinsic fiber cementum layers, in which intensely and weakly stained lamellae (each about 2.5 microm thick) alternate in light microscopic observations. It has been suggested that the alternate lamellar pattern results from periodic changes of the intrinsic fiber arrangement, but owing to the difficulty of observing the fibril arrangement three dimensionally, details were not understood until recently. The NaOH-maceration method has been developed to overcome this difficulty. For the past two decades, we have studied the structure and development of cementum by scanning electron microscopy using NaOH-maceration, as well as by light and transmission electron microscopy, and have accumulated a significant amount of data with regard to the structure and formation of cementum. In light of these data, we have arrived at the following conclusions: (1) The alternate lamellar pattern conforms to the twisted plywood model, in which collagen fibrils rotate regularly in the same direction to form two alternating types of lamellae; one type consists of transversely and almost transversely cut fibrils and the other consists of longitudinally and almost longitudinally cut fibrils. (2) The development of the intrinsic fiber arrangement may be controlled by cementoblasts; the cementoblasts move finger-like processes synchronously and periodically to create alternate changes in the intrinsic fiber arrangement, and this dynamic sequence results in the alternate lamellar pattern.

Ablation of Systemic Phosphate‐Regulating Gene Fibroblast Growth Factor 23 (Fgf23) Compromises the Dentoalveolar Complex

Fibroblast growth factor-23 (FGF23) is a hormone that modulates circulating phosphate (P(i)) levels by controlling P(i) reabsorption from the kidneys. When FGF23 levels are deficient, as in tumoral calcinosis patients, hyperphosphatemia ensues. We show here in a murine model that Fgf23 ablation disrupted morphology and protein expression within the dentoalveolar complex. Ectopic matrix formation in pulp chambers, odontoblast layer disruption, narrowing of periodontal ligament space, and alteration of cementum structure were observed in histological and electron microscopy sections. Because serum P(i) levels are dramatically elevated in Fgf23(-/-), we assayed for apoptosis and expression of members from the small integrin-binding ligand, N-linked glycoprotein (SIBLING) family, both of which are sensitive to elevated P(i) in vitro. Unlike X-linked hypophosphatemic (Hyp) and wild-type (WT) specimens, numerous apoptotic osteocytes and osteoblasts were detected in Fgf23(-/-) specimens. Further, in comparison to Hyp and WT samples, decreased bone sialoprotein and elevated dentin matrix protein-1 protein levels were observed in cementum of Fgf23(-/-) mice. Additional dentin-associated proteins, such as dentin sialoprotein and dentin phosphoprotein, exhibited altered localization in both Fgf23(-/-) and Hyp samples. Based on these results, we propose that FGF23 and (P(i)) homeostasis play a significant role in maintenance of the dentoalveolar complex.

The effect of sample preparation technique on determination of structure and nanomechanical properties of human cementum hard tissue

The mechanical properties of a tissue can be evaluated by determining the response of the structure to mechanical loading. This can be accomplished only when the tissue has been prepared with minimum to no artifacts, thus preserving its structure. In this study it was hypothesized that the structure of cementum is inhomogenous, contributing to a significant variation in mechanical properties of cementum. Therefore, the goals of the study were to identify potential artifacts generated by conventional sample preparation techniques such as polishing and ultrasectioning and subsequently characterize the prepared specimens using an atomic force microscope (AFM) and an AFM-nanoindenter. Comparisons between cryofractured, ultrasectioned and polished specimens concluded that ultrasectioned surfaces have significantly lower average surface roughness ‘ R a’ ( p<0.05). Microstructure of ultrasectioned specimens characterized using an AFM illustrated Sharpey's fibers (SF) and intrinsic fibers (IF) running perpendicular and parallel to the root surface similar to the observed microstructure of cryofractured cementum. In addition, a 10–50 μm wide cementum dentin junction (CDJ) was distinctly observed in the ultrasectioned specimens but not in polished specimens. The SF and CDJ illustrated relatively higher levels of hydrophilicity under wet conditions. The observed inhomogenous microstructure of the ultrasectioned specimens led to a broader range of nanomechanical properties (modulus: 14.2–25.9 GPa; hardness: 0.48–1.09 GPa). However, masking of the same regions such as SF and CDJ due to smeared cementum in polished specimens resulted in a narrower range of nanomechanical properties (modulus: 18.2–20.8 GPa; hardness: 0.79–0.89 GPa). This effect is most noticeable under wet conditions for ultrasectioned specimens (modulus 2.6–10.9 GPa; hardness 0.05–0.30 GPa) compared to the polished specimens (modulus 12.2–14.5 GPa; hardness 0.33–0.45 GPa). Cementum also was shown to be highly viscoelastic, especially when hydrated. The results suggest ultrasectioning of cementum was superior to polishing preparation technique since it allowed visualization of cementum structures similar to cryofractured specimens while providing a flat surface necessary for AFM-based nanoindentation techniques. Additionally, the structural inhomogeneity observed within ultrasectioned cementum contributed to a broader range of mechanical properties.

Structure of Peripheral Cementum of Normal Equine Cheek Teeth

The structure of peripheral cementum of mandibular and maxillary cheek teeth was studied by gross observation, light microscopy, and scanning and transmission electron microscopy. Teeth from four horses aged 4, 8, 17, and 30-years-old were examined. The cementum of the occlusal surface was thicker on the buccal aspect when compared with the lingual aspect of mandibular teeth. The cementum of the occlusal surface was thicker on the palatal aspect when compared with the buccal aspect of maxillary teeth. There was no peripheral cementum on the interdental aspects of either mandibular or maxillary cheek teeth. In the adult tooth, cementum covered the crown and root surfaces. The peripheral cementum of the gingival region showed a dramatic increase in thickness compared with cementum covering the alveolar portion of the embedded tooth. At a microscopic level, three layers (primary, secondary, and tertiary) were identified within cementum. The increase in cementum in the gingival region was of tertiary cementum. All three layers contained vital cementocytes. There was a well-developed vascular system within the cementum. Nerve bundles were also present. Three cementoblast profiles were identified at the junction of the cementum with the periodontal ligament. The results reported in this paper show that cementum is a dynamic vital tissue. These findings should contribute to a greater understanding of the etiology and pathogenesis of cemental caries and periodontal disease in the horse.

Lasers in Periodontology Today and Tomorrow

Summary The concept of periodontal treatment has radically changed over the past decades from a very aggressive surgical approach of pocket elimination to a conservative treatment. The treatment objective today is just removing the periodontal disease causing agents. Regarding this aspect the use of lasers in periodontal treatment may be the next step towards a more conservative treatment. Selective ablation of calculus requires preferential absorption by the material to be removed compared to the healthy tissues. In Periodontology the use of the Nd:YAG laser is restricted to the field of soft tissue management, no ablation of calculus is possible. Using conventional CO2 lasers runs the risk of thermal overheating of the pulp. Moreover due to the absorption characteristics uncontrolled destruction of gingival tissue as well as cementum and enamel occurs. Excimer and Er:YAG lasers can be used to remove calculus but uncontrolled ablation of healthy tooth structure takes place. The frequency doubled Alexandrite (377 nm) laser allows a selective ablation of calculus based on natural differences in absorption. Calculus and microbial plaque are removed quickly and easily while cementum and other healthy tooth structures remain unchanged. In order to establish clinically healthy gingiva and to prevent further loss of attachment the use of the frequency doubled Alexandrite laser seems to be a very promising step for the future of periodontal therapy. Moreover the expectation of a sound maintenance therapy will be fulfilled by using this laser.

The fibrillar structure of cementum and dentin at the cemento-dentinal junction in rat molars

The cemento-dentinal junction was examined in demineralized rat molars with complete roots by scanning electron microscopy combined with NaOH maceration. It is established that the NaOH maceration removes interfibrillar substances and cells from connective tissues selectively without structural damage to collagen fibrils. The cementum was detached from the dentin by the maceration. The inner cementum surface facing the dentin and the outer dentin surface facing the cementum were observed. In acellular cementum, both the outer dentin surface and the inner cementum surface had a smooth appearance. There was little indication of fibrils intermingling between dentin and cementum. In contrast, both the inner cementum surface and outer dentin surface in cellular cementum had an uneven appearance due to the irregular arrangement of collagen fibrils. Point-like protrusions of fibril bundles were observed on both surfaces. Some (not all) of these point-like protrusions appeared to correspond to places of fibrillar intermingling between dentin and cementum.

Topography of periodontally involved human root surfaces after different chemical treatment modalities: an in vitro scanning electron microscopic study.

The significance of chemical and conservative treatments of cemental tissue proximal to periodontal pockets has been pointed out in recent years. This in vitro scanning electron microscopy (SEM) study aimed to investigate the surface effects of topical applications of 0.1% cetylpyridinium chloride (CPC) and 2% sodium lauryl sulfate (SLS) and polishing on the periodontally involved root surfaces of human teeth. Ten single-rooted teeth from 8 patients with advanced adult periodontitis were included. Following extraction, any calculus was removed with extreme care to preserve as much cementum as possible. Eighty root specimens were prepared. Fresh solutions of CPC and SLS were applied for 1, 3 and 5 minutes each to 10 segments of root cementum. A total of 20 segments formed the polished (P) and control (C) groups, respectively. The results showed that the surfaces treated with CPC or SLS differed considerably from polished and control specimens. Depending on time, the surface coating was partly or wholly removed, leaving a nodular cementum structure, uncovering a fibrillar collagen substrate and the openings of dentinal tubules. Scarce debris was present on both control and polished surfaces, whereas bacteria were observed only on the control specimens. In view of these results, further definitive in vitro and in vivo research must be done to determine the advantages of chemical treatment and its effect on periodontal regeneration.