Pathological Resorption Research Articles

Pathologic resorption of the scaphoid: A rare presentation of TB wrist

A 79 year old gentleman, presented to our clinic, complaining of pain and swelling on the right wrist, for two months, complaints being insidious in onset, and progressive for two months. He was evaluated clinically and radiologically, and an x-ray showed features suggestive of atrophic resorbtion of the right scaphoid. A biopsy of the right wrist yielded fibro-collagenous tissue, with epitheloid granulomas, langhans type of giant cells, and surrounding chronic inflammation, which pointed towards a tuberculous lesion. There was neither clinical nor radiological evidence of pulmonary involvement. He was subsequently started on anti-tuberculous chemotherapy. Tuberculosis rarely involves wrist joint and is usually diagnosed in arthritic stage. Similar iteration showed that many patients had a diagnosis of rheumatoid arthritis or nonspecific synovitis prior to the diagnosis of tuberculosis, along with a striking lack of pulmonary symptoms, and a profile which pointed towards tenosynovitis, or rheumatoid arthritis. The scaphoid is the least common bone in the wrist to be affected in a tuberculous focus due to its blood supply. We conclude, tuberculosis of the wrist, should be considered among patients with inflammatory complaints, even in the absence of pulmonary findings. No other case report has been reported on tuberculous reprobation of the scaphoid, from a tuberculous endemic country like India.

Inhibition of TNF-α Reverses the Pathological Resorption Pit Profile of Osteoclasts from Patients with Acute Charcot Osteoarthropathy.

We hypothesised that tumour necrosis factor-α (TNF-α) may enhance receptor activator of nuclear factor-κβ ligand- (RANKL-) mediated osteoclastogenesis in acute Charcot osteoarthropathy. Peripheral blood monocytes were isolated from 10 acute Charcot patients, 8 diabetic patients, and 9 healthy control subjects and cultured in vitro on plastic and bone discs. Osteoclast formation and resorption were assessed after treatment with (1) macrophage-colony stimulating factor (M-CSF) and RANKL and (2) M-CSF, RANKL, and neutralising antibody to TNF-α (anti-TNF-α). Resorption was measured on the surface of bone discs by image analysis and under the surface using surface profilometry. Although osteoclast formation was similar in M-CSF + RANKL-treated cultures between the groups (p > 0.05), there was a significant increase in the area of resorption on the surface (p < 0.01) and under the surface (p < 0.01) in Charcot patients compared with diabetic patients and control subjects. The addition of anti-TNF-α resulted in a significant reduction in the area of resorption on the surface (p < 0.05) and under the surface (p < 0.05) only in Charcot patients as well as a normalisation of the aberrant erosion profile. We conclude that TNF-α modulates RANKL-mediated osteoclastic resorption in vitro in patients with acute Charcot osteoarthropathy.

Automated Recognition of Pathological Resorption Zones in Human Jaw Bones by Computed Tomography

Results of a study of automatic recognition of pathological resorption zones in the image of the jawbone are pre� sented. A criterion for the presence of pathological resorption in the bone is formulated based on statistical inves� tigation. The pathological resorption search method is described as a sequence of algorithmic steps.

Trial shows partial caries removal is an effective technique in primary molars.

Randomised controlled trial in a university setting. Children aged three to eight years, with at least one molar with an acute, deep carious lesion into the dentine were recruited. Treatment took place under rubber dam with decayed dentine being removed completely from the lateral walls of cavities in both groups using round burs operated at low speed. TCR or PCR was then performed in the pulpal wall of each tooth. After caries removal teeth were restored with calcium hydroxide cement and composite resin. Teeth with pulpal exposure were pulpotomised using ferric sulphate. The presence of a fistula, swelling, spontaneous pain and mobility not compatible with root resorption were considered to be clinical signs of failure. Radiolucency at the furcation or in the periapical region and internal or external pathological resorption were considered to be radiographic signs of failure. One hundred and twenty-four teeth in 51 patients were randomised. In the TCR group there were 57 teeth and 38 patients, with 41 patients and 67 teeth in the PCR group. Three patients (four teeth; one PCR and three TCR) dropped out leaving 120 teeth (PCR: n = 66; TCR: n = 54) for analysis. In the TCR group 27.5% (15) teeth in 13 children had pulp exposure compared with one tooth in one child in the PCR group (2%). The mean operative time was significantly higher for TCR (28.1 min; 95% CI: 23.6-32.6 min) than for PCR (17.9 min; 95% CI: 16.3-19.5 min). There was no statistical difference in success rates at 24 months between the groups. The success rate in the TCR group was 96%; (95% CI: 85-99%) compared with 92%; (95% CI: 81-96%) in the PCR group. The clinical and radiographic success rates of PCR and TCR in primary teeth with deep carious lesions were high and did not differ significantly, indicating that PCR is a reliable minimally invasive approach in primary teeth and that the retention of carious dentine does not interfere with pulp vitality. Moreover, PCR provided other clinically relevant advantages over TCR, especially lower incidence of pulp exposure and lower operative time.

Root resorption after dental traumas: classification and clinical, radiographic and histologic aspects

Introduction: One of the most common sequelae observed after dental trauma is root resorption. Objective: The aim of this study was to classify and discuss the external root resorption after a dental trauma, based on a literature review. Literature review: A bibliographic search was performed in the following databases: Medline, PubMed, and Lilacs, from 1997 to 2010. The following descriptors were used: Root resorption, Dental trauma and Classification. From a total of 152 articles found, 25 were selected: 24 in English and 1 in Spanish. Classic articles were also used in our study. External root resorption after dental traumas can be divided into superficial, inflammatory and replacement. It can also be verified in primary dentition as physiological and atypical resorptions. Conclusion: Each type of resorption presents clinical features as well as radiographic and histological aspects. Therefore, the dentist should know these characteristics to perform an early diagnosis and appropriate treatment, minimizing the sequelae related to this problem. Moreover, in primary dentition, the differential diagnosis between physiological and pathological resorption is important to avoid over-treatment.

Chronic calcium pyrophosphate crystal inflammatory arthritis induced by extreme hypomagnesemia in short bowel syndrome

BackgroundShort bowel syndrome (SBS) may induce a plethora of clinical symptoms ranging from underweight to nutrient-, vitamin- and electrolyte deficiencies. The objective of this case report is to illustrate how demanding the management of a 60 year old patient with SBS and recurrent joint attacks was for different medical disciplines.Case presentationThe patient with SBS presented with a body mass index of 16.5 kg/m2 after partial jejunoileal resection of the small intestine with a six year long history of recurrent pain attacks in multiple peripheral joints, chronic diarrhoea and food intolerances. Pain attacks occurred 4–5 times a week with a median consumption of 15 mg prednisone per day. The interdisciplinary workup after several gastroenterologic, rheumatologic, radiologic, psychiatric and orthopedic consultations is shown including successful treatment steps.Clinical diagnosis revealed no systemic inflammatory disease, but confirmed extreme hypomagnesemia (0.2 mmol/l) after reproducible pathological magnesium resorption tests as causative for chronic calcium pyrophosphate crystal inflammatory arthritis (pseudogout, chondrocalcinosis).Multidisciplinary treatment included application of colchicines, parenteral nutrition and magnesium substitution, antiperistaltic agents and avoidance of intolerant foods. Normalization of magnesium levels and a marked remission of joint attacks were achieved after six months with significant reduction of prednisone to 1.5 mg/day.ConclusionDespite the rarity of this condition, it is important to know that hypomagnesaemia may be associated with calcium pyrophosphate crystal inflammatory arthritis (chondrocalcinosis) and that SBS patients may be prone to develop extreme hypomagnesaemia causing recurrent joint attacks without systemic inflammation.

Nonsurgical Endodontic Retreatment of Advanced Inflammatory External Root Resorption Using Mineral Trioxide Aggregate Obturation

Inflammatory external root resorption is one of the major complications after traumatic dental injury. In this case report, we describe treatment of a maxillary central incisor affected by severe, perforating external root resorption. An 18-year-old patient presented with a previously traumatized, root-filled maxillary central incisor associated with pain and sinus tract. Radiographic examination revealed periradicular lesion involving pathologic resorption of the apical region of the root and lateral root surface both mesially and distally. After removal of the root canal filling, the tooth was disinfected with intracanal triple antibiotic paste for 2 weeks. The antibiotic dressing was then removed, and the entire root canal was filled with mineral trioxide aggregate. The endodontic access cavity was restored with composite resin. After 18 months, significant osseous healing of the periradicular region and lateral periodontium had occurred with arrest of external root resorption, and no clinical symptoms were apparent.

Monozygotic twins with idiopathic internal root resorption: A case report

This study presents the first case of internal root resorption in monozygotic twins. Genetic factors have been implicated in the development of root resorption lesions. The link between interleukin (IL)-1 gene polymorphism and root resorption had been reported. However, these studies have involved external root resorption. Twin healthy 17 year old Caucasian sisters were diagnosed with internal root resorption in their upper left central incisor. Neither had a history of orofacial trauma and neither had received orthodontic treatment. The presence of IL-1beta+C3953 allele is the sign of predisposed susceptibility to an exaggerated inflammatory response, including a limited feedback mechanism as a consequence of IL-1RN mutation. Most investigators agree that the listed polymorphism presents a significantly higher risk for development of pathological resorption. These were thought to be cases of true idiopathic resorption as none of the other factors related to root resorption was found.

Goat cryptosporidiosis and its importance at goat production pathology

Goat cryptosporidiosis is parasitic disease with clinical signs at kids at 4-10 days old. Presence of great number of cryptosporidial oocyst is usually in goats without clinical signs of disease. At goats were established Cryptosporidium parvum. Kid cryptosporidiosis had high morbidity and mortality rate. Symptoms of acute cryptosporidiosis include lack of appetite, and weight loss. Clinical signs are yellow diarrhea with odor smell, and some time are present a blood. Animals had abdominal pain, anemia, lost of appetite, dehydration, tenisms, weakens and lost of weight. Occurrence depressive and inactivity. Pathological changes are present in small intestine. In acute cases were thickens gut wall, edema, hyperemia at cecal and colon mucus. There are present numerous hemorrhage, and present of mucofibrinal seam dark brown colored. Those pathological changes drawl resorption and induced clinical signs of disease. Consequence are significant increase of kid accrescense, its weakens and less develop.

Ectopic eruption of the maxillary first permanent molar: characteristics and occurrence in growing children.

The purpose of this study was to determine the characteristics and occurrence of the ectopic eruption of the maxillary first permanent molar in a sample of growing Spanish children. A descriptive, observational, retrospective study was done using the radiographs of 509 consecutive patients, who were in the first phase of mixed dentition. A method was designed to evaluate the amount of pathologic resorption of the second maxillary primary molar and the impaction of the first permanent molar measured in millimeters. Statistical analysis of the studied variables was done using chi-square, analysis of variance, and Pearson correlation coefficient. The frequency of occurrence was 4.3% with no differences in both sexes. Of these, 36.4% were unilateral and 63.6% bilateral with a right:left relation of 3:1. Of the 36 ectopic molars, 69.4% self-corrected spontaneously. In such cases, the pathological resorption of the root of the second maxillary primary molar and its adverse clinical implications were persistent. The relation between self-correction and impaction was 2.27:1. The average impaction on the right side was 2.91 mm and 1.6 mm on the left side. Correlation between the magnitude of resorption and grade of impaction was not observed. Although resorption was found on grades I and II, spontaneous self-correction could occur without arch length loss. However, on grade III or more, therapeutic intervention has to be done. The benefit of early diagnosis and treatment of the maxillary first permanent molar is the prevention of the premature loss of second maxillary deciduous molar and the resulting malocclusion.

Identification of factors associated with pathological root resorption in traumatized primary teeth

The aim of this study was to determine the factors associated with the development of pathological root resorptions in traumatized primary teeth. Based on Dental Reports on Traumatism from the Assistance Program for the Traumatized Patient, 90 children were selected. Among these children, 45 did not present pathological root resorption, while 45 did (23 replacement root resorptions and 22 external inflammatory root resorptions). Possible factors associated with the development of the pathological resorption include: (i) over 18 months or over 52 months of age, (ii) complicated trauma, and (iii) presence of more than one trauma in the same tooth. Using the chi-squared test, it was verified that trauma recurrence was considered to be a factor associated with the development of pathological root resorption (chi(2) = 3.636; P < 0.05). Through the univaried logistic regression test, it was revealed that children with trauma recurrence present a 2.6 times higher chance of developing pathological root resorptions when compared with children that did not report trauma recurrence. Through the univaried logistic regression test, it was also observed that the association of two or three factors caused the chances of pathological root resorption development to increase by 3.8 times in 18-month-old children or older (95% CI: 1.5-9.7) and by 5.1 times in 52-month-old children or older (95% CI: 1.5-17). Trauma recurrence in the same primary tooth is associated with pathological root resorption, and the interaction among two or three factors increases the chance of developing such sequelae.

Success rate of Sealapex in root canal treatment for primary teeth: 3-year follow-up

The aim of this study was to evaluate the clinical and radiographic success of Sealapex pulpectomies in primary teeth. Root canals of 62 primary teeth were filled with Sealapex. The tooth was restored with a stainless steel crown, amalgam, compomer, or glass ionomer cement. Clinical and radiographic evaluations of pulpectomized teeth were performed for up to 36 months afterward. The overall success rate was 92.3%. During the follow-up period, 4 teeth (7.7%) showing periapical lesion and pathologic resorption were extracted and rated as "failure." There were no statistically significant differences between success rate and extent of root canal filling material (P > .05). None of the fillings showed complete resorption in the canals. There were no significant differences among the restorative materials (P > .05). Based on the results of this study it can be concluded that Sealapex can be used successfully in root canal treatment for primary teeth.

Cathepsin K deficiency partially inhibits, but does not prevent, bone destruction in human tumor necrosis factor–transgenic mice

Cathepsin K is believed to have an eminent role in the pathologic resorption of bone. However, several studies have shown that other proteinases also participate in this process. In order to clarify the contribution of cathepsin K to the destruction of arthritic bone, we applied the human tumor necrosis factor (hTNF)-transgenic mouse model, in which severe polyarthritis characterized by strong osteoclast-mediated bone destruction develops spontaneously. Arthritis was evaluated in hTNF-transgenic mice that were either wild-type for cathepsin K (CK(+/+)), heterozygous for cathepsin K (CK(+/-)), or deficient in cathepsin K (CK(-/-)). Arthritic knee joints were prepared for standard histologic assessment aimed at establishing a semiquantitative score for joint destruction and quantification of the area of bone erosion. Additionally, microfocal computed tomography was performed to visualize bone destruction in mice with the different CK genotypes. CK(+/+) and CK(-/-) osteoclasts were generated in vitro, and their proteinase expression profiles were compared by complementary DNA array analysis, real-time polymerase chain reaction, and activity assays. Although the area of bone erosion was significantly reduced in hTNF-transgenic CK(-/-) mice, the absence of cathepsin K did not completely protect against inflammatory bone lesions. Several matrix metalloproteinases (MMPs) and cathepsins were expressed by in vitro-generated CK(-/-) osteoclasts, without marked differences from CK(+/+) osteoclasts. MMP activity was detected in CK(-/-) osteoclasts, and MMP-14 was localized by immunohistochemistry in inflammatory bone erosions in hTNF-transgenic CK(-/-) mice, suggesting MMPs as potential contributors to bone destruction. Additionally, we detected a reduction in osteoclast formation in cathepsin K-deficient mice, both in vitro and in vivo. The results of our experiments raise doubts about a crucial role of cathepsin K in arthritic bone destruction.

Histopathologic study of physiological and pathological resorptions in human primary teeth

This study presents a histological analysis through optical microscopy of primary teeth with physiological and pathological resorptions to outline the histological profile of resorptions. Sixty teeth were examined: 19 primary teeth with physiological resorption and 41 primary teeth with pathological resorption. To analyze the histological conditions of the pulp, periradicular tissue, and the resorption areas, and to investigate the presence, intensity, and location of bacteria, slides were prepared using the hematoxylin-eosin and the Brown-Brenn techniques. For the teeth with physiological resorption, normal pulps and no evidence of bacteria were found. For the teeth with pathological resorption, pulpal alterations, atypical resorption, and bacteria were observed.

Prospective study of standalone balloon kyphoplasty with calcium phosphate cement augmentation in traumatic fractures (G. Maestretti et al.)

The substitution of PMMA with an injectable, osteoconductive material for balloon Kyphoplasty such as calcium phosphate cement (CPC) is highly attractive for obvious reasons. While PMMA is a well known compound in bone and joint surgery, less experience exists with the various CPC compounds and several caveats should however be recognised. CPC is an inherently brittle substance with inferior tensile qualities compared to PMMA. Little is known about the biomechanical behaviour of CPC under long-term cyclic loading in a stand-alone vertebral fracture setting as applied by the authors. Experimentally, cement fissures have been observed under long-term cyclic loading in an osteoporotic vertebral model [2]. In this respect, the authors’ observance of obvious cement cracks in the CT follow-up and an average of 20.3% resorption of applied cement volume is of note. It is not clear whether such marked resorption is part of the expected bone replacement or a pathological resorption process aggravated by fissuring of the material and potential formation of fibrous tissue. The presented histology of the single biopsy in Fig. 6 does not convincingly support substitution of CPC with bone as osteogenesis is not convincingly demonstrated. The authors do not point out where the cement is located, or should be, in the sections in order for the reader to follow their argument of there being no inflammatory reaction. This finding cannot be taken as evidence that inflammation does not occur in those vertebral bodies with significant cement resorption. The case presented by the authors in Fig. 5 shows considerable resorption of cement and partially of the endplate with subsequent loss of the initially excellent correction. Several other cases (2, 7, 10, 11, 16, 20, 22 and 28 in Table 2) also reveal 6–10° progression of segmental kyphosis at follow-up. The CT follow-up of these cases is however not made available and it is not commented on whether these cases presented with a greater degree of cement resorption than those with maintained correction. While these findings do not appear to have had an impact on clinical outcome in this series, they clearly indicate that the knowledge of CPC is not yet sufficient to recommend it for routine application in a stand-alone fashion in vertebral trauma. Further biomechanical investigations with regard to the behaviour of CPC in a stand-alone vertebral fracture model under long-term cyclic loading are needed. Future clinical studies involving any calcium phosphate compound should address the fracture morphology more closely, including the degree of injury of the endplate and vertebral body as described by Oner et al. [1], in order to identify a possible correlation with excessive cement resorption or fissuring.

Bisphosphonates Influence Isoprenylation of Small Gtpases in Human Myeloma Cells.

Zoledronic acid (ZOL), an aminobisphosphonate, is used in the clinic to prevent pathologic resorption of bone by osteoclasts in multiple myeloma. ZOL may also have direct anti-myeloma activity, perhaps through inhibition of farnesyl pyrophosphate (FPP) synthase. FPP synthase is an enzyme in the isoprenoid biosynthetic pathway (step 1 in figure). This pathway is responsible for the production of isoprenoid pyrophosphates. These may be covalently linked to small GTPases; the addition of the 15 carbon farnesyl moiety is termed farnesylation (step 2) and the 20 carbon geranylgeranyl moiety is geranylgeranylation (step 3). These post-translational modifications of small GTPases allow for proper membrane association that is necessary for normal signal transduction. To further elucidate the role of FPP synthase inhibition as a potential mechanism of action of ZOL, a human derived myeloma cell line, RPMI-8226 was incubated with 50 microM ZOL for 24 hours. ZOL diminished isoprenylation of Ras, Rab 6 and Rap 1A, as determined by Western blotting. Addition of 10 microM of geranylgeranyl pyrophosphate (GGPP) restored processing of these small GTPases. Processing was not restored with the addition of 1mM of mevalonate, 10 microM geranyl pyrophosphate (GPP), or 10 microM farnesyl pyrophosphate. As these latter components are upstream of FPP synthase these data suggest that ZOL may act by limiting availability of GGPP for isoprenylation. This is further supported by treatment of RPMI-8226 cells with a novel GGPP synthase inhibitor (step 4), which can be reversed by addition of GGPP but not by FPP. To more accurately mimic the marrow microinvironment, RPMI-8226 cells were incubated in an in vitro co-culture with murine derived osteoclasts. Briefly, bone marrow was harvested from C57B1/6 mice by flushing the long bones with culture media using a 31g needle. The cell suspension was centrifuged for 10 minutes and the cell pellet was resuspended in alpha-MEM containing 10% fetal bovine serum, 20 nM murine GM-CSF, 25nM PTHrP, 50 nM ascorbic acid, 10 nM Vitamin D3 and 1% penicillin/streptomycin. The bone marrow from two long bones was seeded in each 3.5 cm well and non-adherent cells were removed after 24 hours. This created a feeder layer which included osteoclasts, confirmed by TRAP staining. RPMI-8226 (4x106 cells/well) were added to the feeder layer on day six of the culture. The RPMI-8226 cells, normally a suspension cell line, became adherent to the feeder layer by 24 hours. They exhibited >95% viability confirmed by trypan blue exclusion. Under these conditions ZOL impaired protein isoprenylation by reducing geranylgeranylation but not farnesylation. These data further support the critical role of geranylgeranylation but not farnesylation of some small GTPases in myeloma cells. The co-culture system allows for further evaluation of the requirements of protein isoprenylation in myeloma cells and serves as an in vitro model to evaluate the impact of manipulating the isoprenoid pathway on osteoclast-myeloma interactions. [Display omitted]

Endodontic therapy of pathological resorptions of tooth root

Pathological resorptions of a tooth root very often represent both a diagnostic and therapeutical problem. The goal of this study was, based on clinical research on a number of pathological resorptions of various types and localization in relation to time, to analyze and evaluate applied endodontic therapy. Clinical research covered 30 patients (40 root canals in total). 18 teeth (22 canal) with external and 12 (18 canal) with internal root resorptions received endodontic therapy. After standard endodontic procedure had been applied (cleaning and canal shaping) calcium hydroxide paste was used as a canal medicament for cases with internal resorptions and calcium hydroxide paste and points for cases with external resorptions. Canal opturations were done by modified technique of lateral condesation applying AH- Plus paste. The obtained results showed that in cases of internal resorption after 12 months, 11 cases were successful and only 1 failure occurred. In case of external resorption, after the same period of time, 15 cases were successful and failures occurred in 3 cases. The success of resorption treatment depends on many factors but, primarily, it depends on time and accuracy of diagnosis and properly applied treatment and root canal opturation.

Endodontic therapy of pathological resorptions of tooth root

Pathological resorptions of a tooth root very often represent both a diagnostic and therapeutical problem. The goal of this study was, based on clinical research on a number of pathological resorptions of various types and localization in relation to time, to analyze and evaluate applied endodontic therapy. Clinical research covered 30 patients (40 root canals in total). 18 teeth (22 canal) with external and 12 (18 canal) with internal root resorptions received endodontic therapy. After standard endodontic procedure had been applied (cleaning and canal shaping) calcium hydroxide paste was used as a canal medicament for cases with internal resorptions and calcium hydroxide paste and points for cases with external resorptions. Canal opturations were done by modified technique of lateral condesation applying AH- Plus paste. The obtained results showed that in cases of internal resorption after 12 months, 11 cases were successful and only 1 failure occurred. In case of external resorption, after the same period of time, 15 cases were successful and failures occurred in 3 cases. The success of resorption treatment depends on many factors but, primarily, it depends on time and accuracy of diagnosis and properly applied treatment and root canal opturation.

SEM observations of resected root canal ends following apicoectomy.

The purpose of this study was to examine the apical foramen of root apices extracted during apicotomies. A total of 25 teeth extracted from 25 patients admitted to the Department of Conservative Dentistry at Tokyo Dental College's Chiba Hospital were used for the study. All patients were between 22 to 56 years of age at the time of the study, and each of the 25 cases was determined clinically on radiographs to be chronic apical suppurative periodontitis. Microsurgery was performed on all cases, and the extracted root apices were then observed using SEM. The results demonstrated a wide opening, greater than 350 microns as measured along the major axis, of the apical foramen in 80% of the cases. Various characteristics indicative of resorption were observed around the apical foramen. These features included those believed to have been caused by overinstrumentation during root canal treatment as well as irregularly shaped areas presumed to be apical lesions that had enlarged and eroded. We observed a high frequency of manifestations of cementum resorption surrounding the root apices of teeth with apical lesions. Furthermore, we concluded that in the majority of cases in the present study, due to the fact that the apical foramen exceeded normal opening dimensions as a result of overinstrumentation during root canal treatment or resorption around the root apex, prolongation of the lesions had occurred in response to direct contact of microbial infectious matter and tissues surrounding the root apex over a large area. The above finding suggested that, in cases in which the apical foramen is destroyed through overinstrumentation larger than #35 or in which the apical foramen opens up to dimensions greater than 350 microns due to pathologic resorption, surgical intervention may be indicated. On the other hand, in 64% of the cases, an accessory canal was observed in the root apical lesion. Based on this observation, the presence of an accessory canal in the root apex may contribute to some degree to the prolongation of the lesion.

Pulpal reactions to glutaraldehyde and paraformaldehyde pulpotomy dressings in monkey primary teeth.

Abstract Pulpotomy was performed in primary teeth of 4 vervet monkeys to compare the effect of an experimental dressing containing glutaraldehyde (GL) to a similar formula with paraformaldehyde (PF). Forty teeth were examined histologically 2 weeks to 5 months post‐operatively. In the PF group, calcifications were more frequently observed and the central core of tissue in the root canal was heavily laden with debris. Pathologic apical resorption and lesions were more frequent. The pulp in the apical third of the root canal was usually uninflamed in the GL group and peripheral calcifications were seldom observed in it. Reaction to GL seemed, therefore, more favorable clinically. Defects were not observed in the permanent teeth that erupted following shedding or extraction of the experimental primary ones of either group.