Sinus floor elevation using a new bovine bone grafting material: case report and bone grafting materials update / Actualización en materiales de relleno óseo: reporte de un caso clínico de elevamiento del piso del seno maxilar usando un nuevo material de relleno óseo bovino

Bone grafting is important to preserve the alveolar bone ridge height and volume for dental implant placement. Even though implant-supported overdentures present highly successful outcomes, it seems that a great number of edentulous individuals have not pursued implant-based rehabilitation. The cost of the treatment is one of the reasons of discrepancy between highly successful therapy and its acceptance. Therefore, the development of biomaterials for bone grafting with comparable characteristics and biological effects than those renowned internationally, is necessary. In addition, domestic manufacture would reduce the high costs in public health arising from the application of these biomaterials in the dental feld. The purpose of this clinical case report is to provide preliminary clinical evidence of the efficacy of a new bovine bone graft in the bone healing process when used for sinus floor elevation. (AU)

El uso de injertos óseos es importante para preservar la altura y el volumen de la cresta alveolar para la colocación de implantes dentales. Si bien las sobredentaduras implanto-soportadas presentan resultados altamente exitosos, la mayoría de las personas desdentadas no han sido rehabilitadas mediante implantes dentales. Uno de los principales motivos por los cuales los pacientes no aceptan este tipo de tratamiento, altamente exitoso, es el elevado costo del mismo. Por ello, es necesario el desarrollo de biomateriales de injerto óseo con características y efectos biológicos comparables a los reconocidos internacionalmente. Asimismo, la fabricación nacional reduciría los altos costos en Salud Pública derivados de la aplicación de estos biomateriales en el campo dental. El objetivo de esta comunicación es presentar un caso clínico a fin de proporcionar evidencia preliminar acerca de la eficacia de un nuevo injerto de hueso bovino en el proceso de cicatrización ósea en el levantamiento del piso del seno maxilar. (AU)

Mesiodistal dental movement toward remodeled edentulous alveolar ridge: Digital model assessment.

INTRODUCTION: The aims of this study were to compare the changes in posterior dental inclination and angulation, and the posterior tooth crown sizes and alveolar ridge thicknesses consequent to the orthodontic procedures of closing and opening of mandibular first molar edentulous spaces. METHODS: The sample comprised 16 patients (4 men, 12 women) with an initial mean age of 34.17 years and unilateral or bilateral absence of mandibular permanent first molars. The space closure group (SCG) comprised 12 hemiarches with a mandibular first molar edentulous space varying from 2 to 7 mm, orthodontically treated with space closure. The space opening group (SOG) comprised 14 quadrants with a mandibular first molar edentulous space varying from 7.1 to 12 mm, orthodontically treated with space reopening for prosthetic replacement. Digital dental models were obtained before treatment and after space closure or opening, and posterior tooth angulation and inclination, cervico-occlusal crown height, and alveolar ridge thickness were evaluated. Interphase and intergroup comparisons were performed with dependent t tests and t tests, respectively (P <0.05). RESULTS: Mandibular second molar uprighting and changes in buccolingual inclination of the posterior teeth were similar in the groups. The second molar cervico-occlusal crown height increased in the SCG and decreased in the SOG. The alveolar ridge thickness increased in the SCG and remained stable in the SOG. CONCLUSIONS: The only significant intergroup differences were that the second molar cervico-occlusal crown height and the alveolar ridge thickness increased in the SCG, and decreased and remained stable in the SOG.

Multivariate assessment of site of lingual nerve.

Injury to the lingual nerve can cause debilitating symptoms. The nerve lies in the retromolar region and its anatomical site can vary within patients and according to sex, age, and dentate status. To our knowledge, no previous studies have recorded its course from multiple bony landmarks and examined the association between age, dentate status, and sex, in the same sample. We dissected 30 white cadavers and took primary and secondary reference points from the internal oblique ridge. We measured the distance to the lingual nerve in sagittal, vertical, and horizontal planes, and recorded the position where the nerve was closest to the lingual plate. We dissected 46 hemimandibles (23 male, mean age 79 years, range 52-100) of which 26 were from the left side. Mean (SD) sagittal, vertical, and horizontal distances from the primary reference point were 9.29 (3.41)mm, 9.15 (3.87)mm, and 0.57 (0.56)mm, respectively. Mean (SD) vertical and horizontal distances from the secondary point were 7.79 (5.45) mm and 0.59 (0.64)mm, respectively. The proximity of the nerve to the lingual plate varied widely (range -13.00 to 15.17mm from the primary reference point). Dentate status was significant for the sagittal measurement from the primary point, and the vertical measurement from the secondary point. Differences in age, sex, or site of the contralateral nerve were not significant (n=16 pairs). Our findings suggest that the site of the nerve is consistent between and within subjects for sex and age, but not for dentate status. The association between the nerve and the lingual plate varied, which suggests that care must be taken when operating in the area.

Bone density at implant sites and its relationship to assessment of bone quality and treatment outcome.

PURPOSE: To investigate the relationship between bone mineral density (BMD) before implant placement, implant stability measures at implant placement, and marginal bone loss of immediately loaded implants after 1 year in situ. MATERIALS AND METHODS: Consecutively recruited patients received Straumann SLActive implants loaded with fixed provisional prostheses within 24 hours. BMD was measured from computed tomographic images before implant placement. Alveolar bone quality was assessed during surgery. Implant stability-both rotational and as measured with resonance frequency analysis-and marginal bone height were assessed at implant placement and after 1 year. The Pearson correlation coefficient was used to calculate correlations, and significance was considered when P < .05. RESULTS: Twenty-one patients received 137 implants (87 in maxillae and 50 in mandibles). BMD was significantly correlated with bone quality classification in both arches (P < .001). Mean BMD was also significantly correlated with stability values (P < .001). Mean marginal bone loss at implant surfaces differed, but not significantly, at the 1-year follow-up, regardless of BMD values (P = .086) and measured stability (rotational stability P = .34, resonance frequency analysis P = .43) at implant placement. CONCLUSION: Within the limits of this study, it can be concluded that computed tomographic examination can be used as a preoperative method to assess jawbone density before implant placement, since density values correlate with prevailing methods of measuring implant stability. However, in the short time perspective of 1 year, there were no differences in survival rates or changes in marginal bone level between implants placed in bone tissue of different density.

Assessment of vascularity in irradiated and nonirradiated maxillary and mandibular minipig alveolar bone using laser doppler flowmetry.

PURPOSE: The purpose of this animal study was to confirm that laser Doppler flowmetry (LDF) is a reproducible method for the assessment of maxillary and mandibular alveolar bone vascularity and that there is less vascularity in irradiated mandibular and maxillary bone compared to nonirradiated bone. MATERIALS AND METHODS: All maxillary and mandibular premolars and molars of 6 Göttingen minipigs were extracted. After a 3-month healing period, 3 minipigs received irradiation at a total dose of 24 Gy. Three months after irradiation, 5 holes were drilled in the residual alveolar ridge of each edentulous site in each minipig. Local microvascular blood flow around all 120 holes was recorded by LDF prior to implant placement. In 1 irradiated and 1 nonirradiated minipig, an additional hole was drilled in a right maxillary site to enable repeated LDF recordings. RESULTS: The alveolar bone appeared less vascularized in irradiated than in nonirradiated minipigs. The effect of radiation appeared more pronounced in the mandible than in the maxilla. LDF was demonstrated to be a reproducible method for assessing alveolar bone vascularity. However, recordings varied by edentulous site as well as by minipig. CONCLUSION: The authors' hypotheses regarding LDF and vascularity were supported. Further research validating the use of LDF in human beings, especially in those who have undergone radiation therapy for head and neck cancer, is necessary.

Assessment of peripheral dual-energy x-ray absorptiometry measurements in peri-implant bone defects in dogs.

BACKGROUND: The goal of this study was to assess the variability of peripheral dual-energy x-ray absorptiometry (pDEXA) measurements in peri-implant bone defects in dogs. METHODS: Ninety dental implants were inserted in edentulous areas of nine foxhound dogs and standardized peri-implant bone defects were created on the mesial and distal aspect of each fixture (N = 144 total). The animals were sacrificed at 1, 2, and 3 months, respectively. Bone mineral density measurements (BMD) were performed with the use of pDEXA. The calibration of the system was determined by generating four quality control plots using a phantom of known density value. A series of three repeated measurements of the peri-implant sites were made with repositioning of the region of interest. The measurements were performed at the mesial and distal peri-implant sites. The variability of the three BMD measurements was expressed as the coefficient of variation (CV), which is calculated as ([SD/mean] x 100). The difference in the CV between the mesial and distal sites was evaluated using an analysis of variance model for repeated measures accounting for timing of sacrifice (month 1, 2, 3), dog (1 through 9), side (left, right), and adjacent defect regions between implants (1 through 4). RESULTS: The calibration of the pDEXA measured by means of the phantom resulted in a deviation of 0.17%, 0.52%, -0.17%, and 0.00%, respectively, for each of the four assessments. The average CV for the 72 mesial and 72 distal peri-implant sites was 5.22% +/- 4.22% (median 3.50%; range 0.46% to 18.83%) and 5.37% +/- 3.54% (median 4.64%; range 0.22% to 15.35%), respectively. After accounting for timing of sacrifice, dog, side, and position, there was not a statistically significant difference in the CV between the mesial and distal peri-implant sites (P = 0.75). This indicates that the peri-implant site did not significantly affect the variability of the BMD measurements. CONCLUSIONS: This study demonstrated that the pDEXA is a non-invasive, convenient, and fast method to assess BMD around dental implants in animal studies. Limitations of the technique may have a negative impact in the precision of pDEXA when measuring small regions.

The relationship between satisfaction with mouth and number and position of teeth.

A number of studies have suggested that many people are satisfied with less than 28 natural teeth. This review assesses the evidence. The main conclusion was that less than a complete dentition can satisfy oral functional needs. Missing posterior teeth were not very important from a subjective aspect. The demand for replacement of missing teeth is related to the position of missing teeth. Most studies agree that individuals were more concerned about missing anterior teeth and having anterior rather than posterior teeth replaced. Aesthetics is more important than function for a great majority of individuals. However, certain socio-demographic factors, such as age, can change the subjective need for replacement of missing teeth. Some studies have assessed the social and psychological impacts on oral health status. The position of missing teeth was assessed, in terms of groups of missing teeth, anterior or posterior, that would affect an individuals' subjective need for replacement by partial prosthesis. Large numbers of people that have free end removable partial dentures made do not wear them because subjective needs are lower than normatively determined needs for replacement of missing teeth. Some studies have proposed alternatives to the replacement of missing teeth, such as the shortened dental arch concept.

Radiographic assessment of peri-implant vertical bone loss: DICRG Interim Report No. 9.

Vertical bone loss is being assessed radiographically as part of the Dental Implant Clinical Research Group studies through direct measurements on study radiographs taken longitudinally at surgery and recall appointments. Preliminary results and trends for the period between implant placement and 6 months after implant uncovering show more bone loss in implants that are 1) not coated with hydroxyapatite; 2) placed in the maxilla; 3) placed in anterior regions of the jaws; 4) in completely edentulous cases; and 5) placed in bone scored as having lower quality. Confounding relationships between predictor variables will require controlled statistical analyses when data collection is completed.

Implant site assessment using panoramic cross-sectional tomographic imaging.

OBJECTIVES: The purpose of this study was to evaluate the ability of two different panoramic imaging systems to produce cross-sectional images with accurate vertical dimensions of the posterior mandible. STUDY DESIGN: Three partially edentulous human cadaver mandibles were used for this study. On each mandible, three potential implant sites were arbitrarily identified in an area between the mental foramen and the ascending ramus. Each site was imaged using two different panoramic machines. Using each image, the mandible's outline, cortical thickness, and position of the mandibular canal were traced on clear acetate film. The mandibles were then sectioned at each site to serve as a gold standard. The cadaver sections and tracings (corrected for magnification) were measured, recording the overall mandibular height, distance from the crest of the ridge to the superior aspect of the mandibular canal, and the thickness of the cortical bone at the most inferior aspect of the mandible. RESULTS: There were no significant differences between either of the system's image measures and the gold standard when considering the distance between the crest and the mandibular canal. Differences were noted between the systems measures and the gold standard in the assessment of the cortical bone thickness and the overall mandibular height. CONCLUSIONS: Both imaging systems can be useful for vertical measurements of a potential implant site in the posterior mandible.

How much reduction of the dental arch is functionally acceptable for the ageing patient?

Dental care should be aimed at the preservation of a natural functioning dentition for life, within the available resources. In general, preference should be given to dentitions comprising complete dental arches or 14 occluding pairs of teeth. However, in many subjects--such as the elderly--this goal might be neither attainable nor necessary. In these cases, dental care should be aimed at preserving the strategic parts of the dental arch, which are the front and premolar regions (the so-called ultimate occlusal preservation target). Clinical observation as well as research findings indicate that elderly people can function at an acceptable level with a reduced dentition consisting of 10 or even fewer occluding pairs. The minimum size of a functional dental arch differs between individuals and depends on local and systemic factors. Important indicators are the age, the (periodontal) quality of the remaining dentition, the spatial relationship between the lower and upper teeth, the occlusal activity and the adaptive capacity. Dental health care systems should implement guidelines to concentrate the available resources primarily on the strategic regions of the dental arch, especially in high-risk groups. These guidelines should be based on research results. The main objective of this paper is to contribute to defining an acceptable oral status for elderly subjects.