Anatomic assessment of the mandibular buccal shelf for miniscrew insertion in white patients.

INTRODUCTION: Cortical bone thickness, bone width, insertion depth, and proximity to nerves are important factors when planning and placing orthodontic miniscrews. The objective of this study was to anatomically assess the mandibular buccal shelf in a white patient population as the insertion site for orthodontic miniscrews by investigating these 4 variables. METHODS: Measurements were made on cone-beam computed tomography scans of 30 white patients (18 girls, 12 boys; mean age, 14.5 ± 2 years). All measurements were taken adjacent to the distobuccal cusp of the first molar, and the mesiobuccal and distobuccal cusps of the second molar. Additionally, bone depth was measured at 2 height levels, 4 and 8 mm from the cementoenamel junction. Stereolithographic models of patients were superimposed on the cone-beam computed tomography volumes to virtually create an outline of the soft tissue on the cone-beam computed tomography image to allow identification of the purchase point height (mucogingival junction). The inferior alveolar nerve was digitally traced. Miniscrews (1.6 × 10 mm) were virtually placed at the buccal shelf, and their insertion depths and relationships to the nerve were assessed. Analysis of variance with post hoc analysis was used for data analysis. RESULTS: Insertion sites and measurement levels had significant impacts on both cortical bone thickness and bone width. Cortical bone thickness was typically greatest at the distobuccal cusp of the second molar. Bone width was also greatest at the distobuccal cusp of the second molar 8 mm from the cementoenamel junction. The greatest insertion depth was found again at the distobuccal cusp to the second molar, whereas the miniscrews had the greatest proximity to the nerve at this site also. CONCLUSIONS: The distobuccal cusp level of the mandibular second molar is the most appropriate site for miniscrew insertion at the buccal shelf in white patients.

Assessment of Bone Dimensions in the Anterior Maxilla: A Cone Beam Computed Tomography Study.

PURPOSE: To evaluate labial and palatal bone thickness at the maxillary anterior teeth as well as distance from cemento-enamel junction (CEJ) to bone crest using cone beam computed tomography (CBCT). MATERIALS AND METHODS: Measurements were obtained for maxillary anterior teeth of 120 subject CBCT volumes including thickness of labial and palatal plates of bone (coronal, middle, and apical thirds), and distance between CEJ and alveolar bone crest mid-labially, mesially, and distally. RESULTS: The mean value of bone thickness at coronal, middle, and apical thirds of the labial side for central incisor roots were respectively: 0.73, 0.69, 0.60 (mm), for lateral incisors: 0.70, 0.61, 0.49 (mm), and for canines: 0.74, 0.53, 040 (mm). The thickness of palatal bone was significantly larger. The mean distance between CEJ and mid-labial bone crest for all sites was 2.16 mm. CONCLUSION: Labial bone thickness is thin in the vast majority of maxillary anterior teeth. Use of CBCT facilitates planning for immediate implant placement and is helpful in the decision-making process when further bone augmentation is needed.

Assessment of gingival biotype and facial hard/soft tissue dimensions in the maxillary anterior teeth region using cone beam computed tomography.

OBJECTIVE: This study sought to assess the relationship between facial gingival and bone dimensions in maxillary anterior teeth region using cone beam computed tomography (CBCT). DESIGN: This study assessed 621 maxillary anterior teeth in 144 patients. In the sagittal plane, facial bone thickness (BT) and gingival thickness (GT) were measured at the crestal level and at 2, 4 and 6mm apical to the cementoenamel junction (CEJ). The dentogingival complex (DGC) dimensions and the distance from the CEJ to bone crest were also measured on CBCT scans. To determine the gingival biotype, GT at 2mm apical to the gingival margin was measured and GT <1.5mm was categorized as thin while GT ≥1.5mm was categorized as thick. The data were analyzed using SPSS version 21 via repeated measures ANOVA and the Cochrane's Q, chi-square and independent samples t-tests. RESULTS: The BT around the maxillary central and lateral incisors and canine teeth at 4 and 6mm apical to the CEJ was significantly different in thick and thin gingival biotypes (P<0.05). The mean GT at 2 and 4mm apical to the CEJ was significantly different around central and lateral incisors (P<0.05). Thickness of crestal bone was significantly different between the two gingival biotypes around central and lateral incisors (P<0.05). CONCLUSION: The two gingival biotypes had significantly different mean BT; different biotypes and their relationship to BT varied around anterior maxillary teeth.

In Vitro Assessment of Enamel Permeability in Primary Teeth with and without Early Childhood Caries Using Laser Scanning Confocal Microscope.

OBJECTIVE: To compare the permeability of the enamel of primary teeth from individuals free of Early Childhood Caries (ECC) with that from individuals affected with ECC by assessment of dye penetration using Laser Scanning Confocal Microscope (LSCM). STUDY DESIGN: Experimental in vitro study. Exfoliated primary maxillary anterior teeth (n = 44) were collected and divided into two groups (n=22 per group): samples with ECC (Group 1) and without ECC (Group 2). The samples were immersed in Rhodamine B dye solution for 1 day, cut longitudinally into 3 sections, observed using LSCM. Dye penetration depths in the incisal, middle, cervical thirds and on labial, lingual surfaces were recorded. Data were analyzed by the Mann-Whitney test (α = 5%, p < .005). RESULTS: The overall mean penetration depth for group 1 (100.6 µm ± 58.48 µm) was significantly higher than that of group 2 (31.55 µm ± 23.40 µm, p < .000). Mean penetration depth in the incisal, middle, and cervical thirds and on the labial and lingual surfaces of group 1 also presented significantly higher scores than in group 2 (p < .005). CONCLUSION: There was significantly more dye penetration in the ECC group than in the non-ECC group. This could be related to a higher level of enamel permeability in teeth affected with ECC.

Comparative assessment of the effects of Gates-Glidden, Largo, LA-Axxess, and New Brazilian Drill CPdrill on coronal pre-enlargement: cone-beam computed tomographic analysis.

INTRODUCTION: The removal of dentin interferences from the cervical third of root canals is essential for their correct cleaning and shaping and to facilitate access of endodontic instruments to the critical apical region. In mandibular molars, the concavity observed in the furcation area reduces dentin thickness, making this region more susceptible to perforation. The present ex vivo study used cone-beam computed tomographic imaging to compare 3 rotary burs with a new rotary bur recently launched in Brazil (ie, CPdrill; Helse Industry and Commerce Ltda, Santa Rosa, São Paulo, Brazil) regarding the amount of dentin removal from the distal wall of the mesial root of mandibular first molars. METHODS: A total of 40 root canals were selected and randomly divided into 4 groups for cervical preparation: Gates-Glidden burs #2 and #3 (Dentsply Maillefer, Ballaigues, Switzerland), Largo burs #1 and #2 (Dentsply Maillefer), LA-Axxess burs #1 and #2 (SybronEndo, Glendora, CA), and CPdrill burs (1-size only). Dentin thickness in the distal wall of mesial canals at 2 mm from the furcation was measured using I-CATvision software before and after cervical preparation. RESULTS: There was no statistically significant difference between groups regarding residual dentin thickness after instrumentation with the drills (P = .684). CONCLUSIONS: It was concluded that CPdrill is safe for use in cervical preparation of the mesial root of mandibular first molars because it did not promote excessive dentin removal on distal walls.

Assessment of safe zone in maxillary molar region for miniscrew placement in the mixed dentition period--a digital volumetric tomographic (DVT) study.

Assessment of bone thickness in maxillary frst molar region for miniscrew placement during the mixed dentition period with reference to the following variables a) mesio-distal bone width b) buccal cortical plate thickness c) palatal cortical plate thickness d) bucco-palatal bone depth. DVT images of fifteen healthy patients aged 8-10 years with early exfoliated maxillary second deciduous molar were obtained using the Kodak 9000 extra-oral imaging system. The scanned images were analyzed using Kodak dental imaging software [3DmoduleV2.2] and the bone thickness measurements were obtained at six mm and eight mm apical to the cemento-enamel junction. The mean and standard deviation for the measurements was calculated and data was statistically analysed using paired 't' test. The Method error calculations were performed using the Dahlberg formula. The mean values for the mesiodistal width, buccopalatal depth, buccal and palatal cortical bone thickness were found to be sufficient for miniscrew placement up to 1.2mm diameter and 10mm length. The bone thickness measurement and assessment of safe zone in maxillary posterior region from the present study showed potential for miniscrew placement in pediatric age group. Miniscrews can be considered as a promising aid in pediatric space management; so also, they can be used for molar distalization and space regaining in early mixed dentition period.

Radiographic assessment of photodynamic therapy as an adjunctive treatment on induced periodontitis in immunosuppressed rats.

OBJECTIVE: The aim of this study was to assess radiographically the effect of photodynamic therapy (PDT) as an adjunctive treatment to scaling and root planing (SRP) on induced periodontitis in dexamethasone-induced immunosuppressed rats. MATERIAL AND METHODS: The animals were divided into 2 groups: ND group (n=60): saline treatment; D group (n=60): dexamethasone treatment. In both ND and D groups, periodontal disease was induced by the placement of a ligature in the left first mandibular molar. After 7 days, ligature was removed and all animals received SRP, being divided according to the following treatments: SRP: saline and PDT: phenothiazinium dye (TBO) plus laser irradiation. Ten animals per treatment were killed at 7, 15 and 30 days. The distance between the cementoenamel junction and the height of the alveolar bone crest in the mesial surface of the mandibular left first molars was determined in millimeters in each radiograph. he radiographic values were analyzed statistically by ANOVA and Tukey's test at a p value <0.05. RESULTS: Intragroup radiographic assessment (ND and D groups) showed that there was statistically significant less bone loss in the animals treated with PDT in all experimental periods compared to those submitted to SRP. Intergroup radiographic analysis (ND and D groups) demonstrated that there was greater bone loss in the ND group treated with SRP compared to the D group treated with PDT at 7 and 30 days. CONCLUSION: PDT was an effective adjunctive treatment to SRP on induced periodontitis in dexamethasone-induced immunosuppressed rats.

Assessment of parameters affecting the presence of the central papilla using a non-invasive radiographic method.

BACKGROUND: This study was performed to assess the relationship between radiopaque landmarks and central papilla presence and height. The probability of the presence of a central papilla has been related to the bone crest-contact point distance. Papilla height has been measured by inserting a dental probe under local anesthesia, but this method is invasive. It would be desirable to assess the influence of other dental landmarks on the presence and height of the papilla and to use a non-invasive method for measurement of papilla height that is simple, accurate, and accepted readily by patients. METHODS: Periapical radiographs were obtained in 310 adults with fully erupted permanent dentition, healthy gingiva (plaque and gingival indexes of 0 to 1), and well-aligned maxillary central incisors. Semisoft radiopaque material was placed to fill the space coronal to the papilla tip, which enabled it to be visualized without probing. Vertical and horizontal distances were measured with an electric ruler. RESULTS: The presence of a full central papilla was related significantly to age, papillary height, and distances from the bone crest to the contact point, the buccal cemento-enamel junction, and the proximal cemento-enamel junction. When confounding factors were controlled using multifactorial logistic regression, the distance from the bone crest to the proximal cemento-enamel junction was the strongest determinant of papilla presence. CONCLUSIONS: Standard periapical radiography is a non-invasive method that can be used to study determinants of the presence of a central papilla. The factors linked to papilla recession were age, bone crest-contact point distance, bone crest-proximal cemento-enamel junction distance, and papilla height. Bone crest-proximal cemento-enamel junction distance, the strongest predictor of the probability of papilla recession, might be used to predict this probability after prosthetic or orthodontic interventions.

The flaws in tooth root resorption assessment algorithms: the role of source position.

OBJECTIVES: The purpose of this project was to analyse the effects of X-ray source location on mathematical compensations used in the clinical assessment of external apical root resorption (EARR). METHODS: Using geometric constructions, governing equations were derived to express the relationships between actual tooth, root and crown lengths, and their image sizes on "before" and "after" radiographs. RESULTS: Good agreement was found between calculated and published experimental results. More importantly, errors associated with the assessment methods are demonstrated. CONCLUSION: It is established that root resorption assessment algorithms cannot reliably compensate for the inherent distortions in radiographic evaluations of EARR, even in the best-case scenario of an idealized, precisely characterized, linear tooth.

The bitewing radiograph as an assessment tool in fixed prosthodontics.

Molar crown preparations, as described in the literature, have standard forms dictated by the demands of retention, resistance and the physical properties of materials. Standard designs may not be appropriate for all patients because of ethnic variations in tooth shape, pulp size and dentine thickness. Accurate data on these features could assist clinicians to minimize the risk of accidental pulpal injury. The aim of this study was to compare the first molar crown and pulp dimensions between Asian (Chinese, Korean, Malay) and other ethnic groups, using measurements from the bitewing radiographs of 121 subjects. Comparisons revealed the following significantly different features of Asian first molars: larger total pulp areas in uppers (P < 0.0005); shorter crowns (P < 0.0005); narrower upper teeth at the cervix (P < 0.0005); wider pulps at the cervix of lowers (P < 0.02); more bulbous crowns (P < 0.0005 for uppers; P < 0.01 for lowers), and finally significantly thinner dentine interproximally at the cervix (P=0.001 for uppers; P=0.011 for lowers). Preparations with wide shoulders could pose hazards to the pulps in Asian subjects. This study emphasizes the value of bitewing films in assessing crown and pulp size and shape before making crown preparations. The experienced practitioner may intuitively include tooth and pulp morphology in treatment planning, but this appears not to be taught or documented in textbooks.

Comparison between panoramic and intra-oral radiographs for the assessment of alveolar bone levels in a periodontal maintenance population.

BACKGROUND: Information about the agreement between intra-oral (I-O) and panoramic (OPG) radiographs is limited. AIMS: : (1) To assess the agreement between I-Os and OPGs for direct measurements of the distance between the cemento-enamel junction (CEJ) and the alveolar bone level (BL) as well as the proportional values in relation to the root length (CEJ-BL/root length), and (2) to explore the symmetry between the left- and right-side measurements. MATERIAL AND METHODS: I-Os and OPGs were studied in 292 periodontal maintenance subjects (mean age 55.5 years, SD+/-12.6) with on average 22.4 teeth (SD+/-4.1 range: 6-28). The images were measured using a PC software program. Site-based I-O and OPG values for CEJ-BL as well as CEJ-BL/root length were compared. OPG values of CEJ-BL/root length values between the left and right sides were also studied. RESULTS: A total of 11,395 linear distances (CEJ-BL plus CEJ-apex) from the I-Os and 21,462 linear distances from the OPGs were measured. The intra-class correlation coefficients (ICCs) between sets of readings of CEJ-BL varied between 0.80 and 0.89 (p<0.001), with the best agreement for tooth 22 (ICC: 0.89; 95% CI: 0.83-0.92). The ICCs for CEJ-BL/root length varied between 0.54 and 0.92. Mean differences between I-O and OPG values were in the 0.00-0.04 mm range for the CEJ-BL/root length comparisons. The maxillary anterior sextant demonstrated a 1.4 x enlargement by OPG for the CEJ-BL/root length comparisons. No distortions were observed for mandibular sextants. Left- and right-side symmetry of periodontal bone loss was demonstrated. ICC varied between 0.79 (95.00% CI: 0.71-0.84, p<0.01) and 0.53 (95.00% CI: 0.36-0.65, p< 0.01). CONCLUSIONS: I-O and OPG radiograph readings are in great agreement. Alveolar bone loss appeared to have a symmetrical distribution pattern. Hence for periodontal assessments, OPG radiographic readings may, at least in part, substitute for full-mouth periapical radiographic evaluation.

Assessment of root curvature and distance using computed tomography.

The safety and efficacy of subgingival root surface instrumentation may be enhanced by optimized adaptation between instrument and treated surface. Thus, detailed knowledge of root geometry may allow advances in instrument design. The aim of this study was therefore to measure root radii of various tooth types as well as distances between tooth roots using computed tomography. Two hundred sixteen teeth in eight patients were studied, with cross sections of teeth at the level of the cemento-enamel junction (CEJ) being regarded as ellipses. The maximum radii of ellipses were calculated and averaged for each tooth surface within various tooth groups. In addition, the spacing between roots at CEJ level and 5 mm below the CEJ was measured. Mean radii varied from 1.09+/-0.50 mm (lower incisor, lingual) to 13.7+/-0.96 mm (upper molar, mesial). Radii of 1 mm to 6 mm were most frequently found at buccal, palatal, and lingual surfaces, whereas the majority of radii were between 2 mm and 11 mm at mesial and distal sites. Root distance varied between 1.04+/-0.49 mm (lower incisors, CEJ level) and 2.81+/-1.70 mm (lower molars, 5 mm below CEJ). The curvature of an instrument for root surface instrumentation should correspond to a radius of at least 11 mm to achieve maximum adaptation to the treated surface, and the width of the working end should be less than 1 mm to allow sufficient interdental instrumentation.

Radiographic assessment of the alveolar bone height in children and adolescents with familial dysautonomia.

PURPOSE: Familial dysautonomia (FD) is a progressive neuropathy, characterized by somatic and skeletal abnormalities, and by a variety of oral and diet disturbances. The purpose of the study was to assess the alveolar bone height at the molar areas of children and adolescents with FD. METHODS: The distance from the cemento-enamel junction (CEJ) to the alveolar bone crest (ABC) was measured on routine diagnostic bitewing radiographs of nine males and seven females with FD (mean age = 122 months) and in those of two matching groups (C1 = 119 months; C2 = 122 months). RESULTS: The mean values for the maxilla were significantly larger than those in the mandible. A positive significant correlation was found between the CEJ-ABC measurements of the primary and the permanent teeth, and between the CEJ-ABC measurements and age. The mean values per patient for the CEJ-ABC distances of the FD group were smaller than the control groups, but the difference was not statistically significant. The CEJ-ABC measurements in the primary and the permanent molars were smaller in the FD group, and in the premolars and permanent cuspids they were larger than those in the two control groups. These differences were not statistically significant. No differences were found between the FD and the control groups in the primary cuspids. CONCLUSIONS: The alveolar bone height of children and adolescent with familial dysautonomia does not differ from that of healthy controls.

Radiographic detection and assessment of the periodontal endosseous defects.

AIMS: The aim of the present study was to investigate the potential of conventional radiography in detecting and accurately imaging periodontal endosseous (or osseous) defects when compared to surgical measurements. A further objective of the study was the selection of the most successful radiographic method for the assessment of endosseous defects. METHOD: Surgical measurements, during periodontal flap surgery, and radiographic measurements, from periapical and panoramic radiographs, were obtained from 5,072 proximal surfaces of 100 patients presenting with periodontitis. RESULTS: Statistical evaluation of the surgical and radiographic measurements revealed the following. (1) The ability of the radiographs to detect periodontal osseous defects was relatively low. (2) For periapical radiography, it depended, in descending order, on the depth and buccolingual width of the defect, the number of osseous walls and the jaw location. For panoramic radiography, it depended only on buccolingual width. (3) Osseous defects of small depth and/or small buccolingual width were the most difficult to detect radiographically. (4) Periapical radiography was more successful than panoramic in detecting osseous defects, and more accurate in assessing the defect dimensions (depth, mesiodistal width). (5) The difference in the defect detection ability between the 2 radiographic methods, the accuracy of the radiographic defect dimensions assessment as well as the degree of agreement between periapical and panoramic assessment depended on defect location and dimensions. CONCLUSIONS: Periapical radiography is superior to panoramic in detecting and accurately imaging periodontal osseous destruction.

Clinical and radiographic assessment of Class II esthetic restorations in primary molars.

PURPOSE: The aim of the study was to access the clinical performance of two esthetic materials (Vitremer and Z100 + Scotchbond Multipurpose) when used as Class II restorations in primary molars, and compare them to amalgam controls. METHODS: A total of 102 restorations were placed in primary molars of 29 schoolchildren; 40 were of Vitremer, 38 of Z100 + Scotchbond Multipurpose, and 24 of amalgam (Dispersalloy). The restorations were evaluated clinically at baseline and after 6, 12, 18, 24 months, or until tooth exfoliation or patient drop-out, following the modified Cvar and Ryge criteria. Radiographs were taken at yearly intervals, and the radiograph of the last examination available was assessed and scored. RESULTS: The majority of the restorations examined clinically up to 18 months was good (Alpha according to Cvar and Ryge), and no statistically significant differences between the groups was observed. However, at the 19-24 months evaluation, Z100 rated better than Vitremer for surface appearance and color match. The prevalence of radiolucent defects at the cervical margin for the Z100 (47%) was significantly higher than for amalgam (11%) restorations (P = 0.002) and for Vitremer (13%) restorations (P = 0.008). CONCLUSION: The three materials evaluated (Vitremer, Z100 and Dispersalloy) presented satisfactory clinical performance during the time evaluated (approximately 2 years). Approximately half of the composite resin restorations presented radiographic defects that might require replacement at a later date. In contrast, glass ionomer and amalgam restorations presented significantly less radiographic defects at the time of the final examination. This study suggests that composite resins are indicated for classII restorations in primary molars that are expected to exfoliate within two years.

Assessment of alveolar bone levels from intraoral radiographs in subjects between ages 15 and 94 years seeking dental care.

Studies have shown that <20% of the US population has periodontal disease. Studies of radiographs have shown that alveolar bone loss increases with age. Bone loss assessed from intraoral radiographs describing 10,282 teeth from 416 subjects seeking dental care during a 3 month period at the University of Washington were studied. The mean age of the subjects was 47.2 years (SD+/-15.2). The youngest subjects (15-24) had on average 29.6 teeth (SD+/-2.2) and the oldest subjects (75-94) 19.3 teeth (SD+/-6.6). This difference was statistically significant (F=16.57, p<0.001). No association was found between alveolar bone loss (CEJ-ABC), and TMD symptoms. Smoking was significantly associated with both general bone loss (CEJ-ABC) (chi(2)=114.9, p<0.0001), and vertical bone defects (angular) (chi(2)=101.8, p<0.0001). In this study population (15-94 years), alveolar bone loss progressed as defined by the slope (beta=0.29) between age 15-44, but was almost flat from age 50 years (beta=0.04). The data suggested an overall rate of alveolar bone loss of 0.02 mm per year. Stepwise multiple regression analysis showed that smoking was the primary factor in bone loss (t= 7.7, p<0.0001), followed by age (t=7.0, p<0.001) and gender (t=3.0, p<0.01). TMD symptoms could not explain the presence and severity of horizontal or vertical defects. If the CEJ-ABC distance above the mean plus 2x the SD was used as the cutoff value to define abnormal bone levels, 10.9% of the younger (15-45 years), and 10.7% of the older subjects (50-94) had significant alveolar bone loss. 73.9% of the younger and 100% of the older subjects with such extent of alveolar bone loss were smokers.

Selection of the most accurate method of conventional radiography for the assessment of periodontal osseous destruction.

The purpose of the present study was to compare the radiographic measurements of periodontal osseous destruction with the surgical measurements, which represent the true value of osseous destruction, and to select the most successful method of conventional radiography in detecting and accurately assessing periodontal osseous destruction. A total of 5072 proximal surfaces in 2536 teeth of 100 patients with periodontitis were evaluated surgically during periodontal flap surgery and radiographically by using periapical and panoramic radiography. Comparative evaluation of the measurements obtained by these 3 different methods of osseous destruction assessment revealed the following. (1) The radiographic detection ability of small osseous destruction (1-4 mm) was very low for both methods of assessment and became even lower for the initial osseous destruction (1 or 2 mm). (2) Periapical radiography was more successful than panoramic in the detection of osseous destruction, especially of the small destruction (4.7x). (3) Panoramic radiography underestimated the osseous destruction, whereas periapical radiography was relatively accurate in the osseous destruction assessment. (4) Periapical radiography was more accurate in the osseous destruction assessment than panoramic, regardless of the location of the dental surfaces (jaw, tooth group, mesial or distal) and the degree of osseous destruction. (5) The deviation of the radiographic measurements of osseous destruction from the surgical measurements, as well as the difference between the two radiographic methods, depended on the jaw location, the tooth group and the degree of osseous destruction. (6) The radiographic assessment of osseous destruction underestimated the osseous destruction in initial periodontitis, it was relatively accurate in moderate periodontitis, but overestimated it in severe periodontitis. The radiographic measurements of osseous destruction deviated least from the surgical measurements in the group of moderate periodontitis and most in that of severe osseous destruction. (7) The 2 radiographic methods agreed most in the assessment of osseous destruction in the severe periodontitis group and least in the initial periodontitis group. (8) The indirect Schei method was less successful in detecting the small osseous destruction and less accurate in assessing the osseous destruction than the direct millimetric method of radiographic evaluation. (9) The osseous destruction as assessed from periapical radiographs by the Schei method was not significantly different from that assessed by the radiopaque Fixot-Everett grid. The results of the present study suggest that periapical radiography is more successful in detecting periodontal osseous destruction and more accurate in assessing it than panoramic radiography.