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PubMed1995

Observations of root surfaces from patients with early-onset periodontitis and leukocyte adhesion deficiency.

The purpose of this investigation was to report observations of the root surfaces of teeth from 2 siblings with leukocyte adhesion deficiency (LAD). In previous publications, the clinical, radiographic and immunologic findings in the family were presented. 38 permanent teeth from the 2 siblings were prepared for microscopic examination, 11 for light microscopy (LM), and 27 for scanning electron microscopy (SEM). In addition, 8 healthy teeth obtained from 2 patients requiring extractions for orthodontic treatment served as controls. LM observations on healthy teeth revealed cementum with normal structural appearance which exhibited a mosaic or mogul-like pattern with SEM. In LAD specimens, cementum apical to the dentogingival junction exhibited resorption lacunae and areas of poor structural definition characterized by aplasia and hypoplasia (hypomineralization). Areas of hypoplasia presented as distinct irregular surfaces with a pebbly or globular-like appearance. Alteration in cementum formation and maturation may play a role in the etiology of early-onset periodontitis.

Adolescent↗
PubMed1995

Effects of citric acid treatment on the Ca, P and Mg contents of human dental roots.

An electron microprobe analyser associated with a scanning electronic microscope was used to measure Ca, P and Mg contents of the human dental root hard tissues, before and after a citric acid treatment (pH = 1). The measurements were made on transverse sections through the cervical 1/3 of the molar roots. The measurements were performed at the following 8 levels: the internal cementum, the cementum-dentine junction, cementum-related dentine, 4 external dentine levels located at 220 microns, 420 microns, 620 microns and 820 microns from the cementum-dentine junction, and finally the juxta-pulpal dentine. After the citric acid treatment, the losses in Ca and P, but not in Mg, varied significantly with the level; an acid-resistant dentine layer of approximately 600 microns was found under the cementum-dentine junction. An increase in the Ca/P ratio was also observed in this layer. Since this external dentine zone is less demineralized by the citric acid than the underlying dentine, the collagen matrix in this region may also be less exposed. These differences in the response to citric acid that depend on the distance from the root surface may explain the unpredictability of periodontal healing after citric acid treatment of diseased root surfaces, because the amount of tissue removed during root planing is not constant.

Calcium↗
PubMed1996

Extraoral apical elongation of deeply damaged roots with titanium posts. A comparison of 2 methods.

42 very deeply fractured or otherwise damaged single roots which could not be saved by intra-alveolar transplantation only were replanted to a supragingival level after extraoral transapical elongation by either an ordinary titanium root screw (method 1) or a specially designed titanium post (TransApex, Dentatus) (method 2). After observation periods of x = 73 months (method 1) and x = 34 months (method 2), 61% and 85% of the cases-respectively, were considered successful, fulfilling all 5 predefined success criteria. No other resorptions than slight surface resorptions were seen and all teeth showed very shallow pocket depths and physiological mobility, indicating that the long extraoral treatment had not caused lasting traumatic injury to the PDL cells. The most frequent complication in method 1 was periapical osteitis, indicating that the elongation system had become insufficient. On the other hand, the method showed the capacity to heal many of the pre-existing osteitis cases. Both root elongation techniques described in this report are comparatively inexpensive and safe, since the apical elongation is never extended beyond the lamina dura structure of the alveolus. Method 2 is to be preferred, however, as the specially designed through-and-through post-system which simultaneously provides apical closure, transapical elongation and coronal retention, allows treatment of even very short roots and seems to give better results.

Adolescent↗
PubMed1990

Light and ultrastructural studies of human chronic periapical lesions.

Forty clinically chronic periapical granulomas and cysts and their corresponding teeth were removed. Diagnosis was by light and transmission electron microscopy. Ultrastructural features of the root surfaces concerned and the corresponding soft tissue were detected by scanning electron microscopy. Chronic periapical inflammation had caused root resorption which affected the cementum and/or the dentin. There were no ultrastructural differences between granuloma- and cyst-induced root resorption. Resorption lacunae were devoid of epithelial and connective tissue attachment. However, root surface exposed to granulomas and cysts also indicated spontaneous cementum repair. Moreover, at their periphery, cellular debris, cells defined as fibroblasts, and cell projections and fibrils could be seen which were continuations of the periodontal ligament.

Adolescent↗
PubMed1980

A model for experimental endodontics by transplanting human dental roots subcutaneously to rats.

In 35 roots from extracted human teeth the pulp tissue was removed and the specimens autoclaved before being transplanted subcutaneously to rats. The animals were sacrificed 7, 14, 21, 90 and 140 d after transplantation and the skin and subcutaneous tissue containing the transplants were prepared for histologic examination. The human roots were well tolerated by the rats with a fibrillar connective tissue capsule surrounding the specimens. In the 90-d and 14-d groups a few root surfaces exhibited small resorption lacunae. The empty root canals became slowly occupied by a maturing granulation tissue occasionally containing foci of lymphocytes. After 140 d the canal tissue was still highly vascular with multinuclear giant cells occasionally located along the dentin walls but no internal resorption was recorded. It is concluded that this model may be useful for systematic testing of root filling materials concomitant with human studies.

Animals↗
PubMed2005

Fluoride release and secondary caries inhibition by adhesive systems on root dentine.

This study tested the fluoride-release rate and the root caries inhibitory effect of dental adhesives. In phase 1, the fluoride released from samples (n = 5) of the adhesives A (Optibond Solo), B (One-up Bond F), C (Prime & Bond NT), D (Tenure Quick), and also of the controls [+] (glass-ionomer cement) and [-] (non-fluoride releasing adhesive), was quantified on a daily basis during a pH-cycling, caries-simulating phenomenon. In phase 2, restorations were made in bovine root dentine slabs (n = 16) with the same adhesives associated with a non-fluoridated composite. Control [+] restorations were made entirely with glass-ionomer cement. Specimens were thermocycled and submitted to the pH-cycling regimen. Demineralization areas and the presence of the wall lesion (WL) and the inhibition zone (IZ) were determined by polarizing light microscopy in dentine adjacent to the restoration. The highest concentration of fluoride was released by the control [+]; adhesives A, B and C, also released fluoride. No detectable amount of fluoride was released by D or [-]. Smaller areas of demineralization were found with control [+], whereas the demineralization areas of adhesives A-D and [-] did not differ from each other. No WL was detected, and higher percentages of IZ were recorded to [+] and to adhesive A. Although some dental adhesives were able to release fluoride, they could not inhibit secondary caries development as well as the glass-ionomer cement.

Animals↗
PubMed1989

Patterns of healing on replanted baboon incisors coated with an allogeneic fibrin-fibronectin protein concentrate.

This study investigated the use of an allogeneic fibrin-fibronectin protein concentrate (AFFP) in preventing ankylosis and root resorption on replanted teeth during healing. In 2 adult male baboons (Papio ursinus) after extraction of the mandibular incisors, the coronal two-thirds of the exposed roots were planed to remove the remnant of the periodontal ligament and the cementum. The exposed dentinal surfaces were demineralized with citric acid at pH 1 for 3 min and notched at the junction between the planed and non-planed surfaces. Before replantation, the experimental roots and alveoli were coated with the AFFP prepared from pooled fresh-frozen baboon plasma. The animals were killed 55 days after operation and histometrical analysis was performed on serial sections cut in the buccolingual direction parallel to the long axis of the recovered specimens. An analysis of variance demonstrated significant differences between the two treatments with regard to the magnitude of ankylosis (greater for citric acid-demineralized plus AFFP-treated surfaces). There were variations in the magnitude of the different patterns of healing both between and within the experimental and control surfaces. Within the limits of the study, in this primate replantation model, the biochemical treatment of surgically exposed and demineralized root surfaces with AFFP did not enhance connective tissue attachment regeneration nor prevent dentoalveolar ankylosis and root resorption.

Alveolar Process↗
PubMed2004

Detection of subgingival calculus and dentine caries by laser fluorescence.

OBJECTIVES: Detection of subgingival calculus and dentine caries in the bottom of deep periodontal pockets is often difficult without visual observation. We thus examined the possibility of its detection using autofluorescence induced by laser irritation. METHODS: Autofluorescence was measured at various excitation and emission wavelength settings in five specimens each of sound dentine and enamel, subgingival calculus, and root caries. Periodontopathic model teeth with bacterial cells and blood clots were also irritated by laser to obtain autofluorescent images. RESULTS: Subgingival calculus and dentine caries showed a characteristic 700 nm emission when excited at 635 nm or a 720 nm emission when excited at 655 nm; sound dentine or enamel, however, did not. The calculus differentiation power, however, was higher with excitation at 635 nm than at 655 nm. The autofluorescent images photographed at an excitation of 633 nm provided clear calculus identification in periodontopathic model teeth when a 700 nm band-pass filter or a 700 nm high-pass filter was used. However, fluorescence intensity was masked when the calculus surface was covered by bacterial cells or blood clots. For clinical use, it would be important to remove subgingival plaque and debris from root surfaces before attempting to detect subgingival calculus and root caries with this manner. CONCLUSION: The autofluorescence method employing excitation of 633-635 nm was found to be a powerful tool for detecting subgingival calculus and root caries.

Actinomyces viscosus↗
PubMed2006

Effect of two different approaches for root decontamination on new cementum formation following guided tissue regeneration: a histomorphometric study in dogs.

BACKGROUND AND OBJECTIVE: The aim of the present study was to evaluate comparatively the effect of two different approaches for root decontamination on new cementum formation following guided tissue regeneration (GTR). MATERIAL AND METHODS: Nine mongrel dogs were used to obtain bilateral chronic class III furcation defects by placing cotton ligatures around both third mandibular premolars. The teeth were randomly assigned to receive one of the following treatments: scaling and root planing, by means of hand and rotatory instruments, in order to remove soft and hard deposits as well as all root cementum (group A); or removal of only soft microbial deposits, by polishing the root surface with rubber cups and polishing paste, aiming for maximum root cementum preservation (group B). Both groups were treated with GTR, with the use of resorbable polyglycolic-lactic acid membranes (RESOLUT XT). RESULTS: Four months later, data analysis showed that a superior length (mm) (3.59 +/- 1.67 and 6.20 +/- 2.26 for groups A and B, respectively; p = 0.004) and a thicker layer (microm) (18.89 +/- 9.47 and 52.29 +/- 22.48 for groups A and B, respectively; p = 0.001) of new cementum was achieved by keeping the root cementum in place during root decontamination (group B). Regardless of the treatment modality, the new cementum was predominantly of a reparative, cellular extrinsic and intrinsic fiber type. CONCLUSION: Within the limits of the present study, it may be concluded that root cementum preservation may affect the new cementum formation following GTR in class III furcation defects, and the treatment modality did not influence the type of newly formed cementum.

Animals↗
PubMed1989

Dynamics of dentoalveolar ankylosis and associated root resorption.

The present experimental studies in monkeys were undertaken to study the initiation and progression of dentoalveolar ankylosis of replanted teeth and associated root resorption. Maxillary and mandibular lateral incisors were extracted and replanted after an extraoral period of 15 min or 1 h. Teeth with an extraoral period of 1 h were endodontically treated. Half the number of monkeys were given antibiotics at the time of replantation. The observation periods varied from 2 days to 40 weeks. Irrespective of the length of the extraoral period, initial root resorption and minor areas of ankylosis were found 1 week after replantation. The initial ankylosis was not preceded by root resorption. In teeth replanted after an extraoral period of 15 min the ankylotic area did not increase with increasing time after replantation. Instead the periodontal membrane was re-established, separating the root surface from the alveolar bone. In teeth replanted after an extraoral period of 1 h, the initial ankylotic area increased with increasing time after replantation. Eight weeks and more after replantation, most of the periodontal membrane was replaced by bone covered by osteoblasts and occasional osteoblasts that were in continuity with the endosteal cells outlining the marrow spaces of the alveolar bone. The cementum and dentin were then gradually resorbed with increasing time after replantation. Antibiotics given at the time of replantation reduced the initial inflammation in the periodontal membrane and the inflammatory root resorption after all observation periods and it also seemed to some extent to prevent bacteria from entering the necrotic pulp tissue. Based on the present results it is suggested that root resorption associated with dentoalveolar ankylosis is initiated by endosteal osteoblasts and is thus a hormonally regulated process. This is in contrast to inflammatory root resorption, which seems to be triggered by inflammatory cells.

Animals↗