• Users Online: 63
  • Print this page
  • Email this page

Table of Contents
Year : 2018  |  Volume : 6  |  Issue : 3  |  Page : 21-26

The outcome of in vivo use of Equator attachment systems with implant-supported maxillary overdenture on patients’ satisfaction and biochemical measuring of MMP-8

1 Department of Oral and Maxillofacial Prosthodontics, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
2 Department of Oral and Maxillofacial Prosthodontics, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia; Department of Removable Prosthodontics, Faculty of Dentistry, Alexandria University, Alexandria, Egypt

Date of Web Publication17-Jan-2019

Correspondence Address:
Dr. Manal R Alammari
Department of Oral and Maxillofacial Prosthodontics, Faculty of Dentistry, King Abdulaziz University, P. O. Box 80209, Jeddah 21589
Saudi Arabia
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/INJO.INJO_12_18

Rights and Permissions

Background: Management of completely edentulous dental patients with compromised oral condition has become a prime concern for dental professionals. Treating patients who were edentulous with an overdenture supported by osseointegrated implants and retained by small diameter attachment system is a highly valuable rehabilitation treatment for older adults. Purpose: To evaluate patients’ satisfaction by oral health–related quality of life who received maxillary implant–assisted overdentures (MIAO) constructed with OT-Equator attachment clinically as well as biochemical measuring of matrix metalloproteinase-8 (MMP-8) in the peri-implant soft tissue. Material and Methods: This study included 25 patients rehabilitated with MIAO with OT-Equator attachments that screwed to the abutments and mandibular removable partial denture restoring up to second premolars. Biochemical evaluation of collagenase-2 (MMP-8) in peri-implant soft tissue was carried out using sandwich enzyme immunoassay–enzyme-linked immunosorbent assay (ELISA) kit. Then oral health impact profile index was used as a shortened 14-item questionnaire to evaluate the impact of oral health on the quality of life. Results: Collagenase-2 (MMP-8) in the peri-implant sulcular fluid revealed a statistically significant difference in different periods (F = 56.649). Five domains showed a statistically significant improvement at 5% level (functional limitation [P = 0.001], physical pain [P = 0.037], psychological discomfort [P = 0.007], physical disability [P = 0.010], and psychological disability [P = 0.016]) except domains regarding social disability and handicap that showed no significant improvement. Five of the seven domains of the oral health related quality of life (OHIP-14) questionnaire showed a statistically significant improvement at 5% level (functional limitation [P = 0.001], physical pain [P = 0.039], psychological discomfort [P = 0.007], physical disability [P = 0.010], psychological disability P = 0.017]). Conclusion: Results showed that the patients with MIAO were satisfied with their oral health–related quality of life. Expectable and encouraging treatment outcomes among elderly patients in severe situations with bone deficiency in the maxilla can be achieved with OT-Equator attachments. Biochemical analysis of collagenase-2 (MMP-8) was a potential host marker for the condition of peri-implant tissue as it could prevent failure of dental implant.

Keywords: Biochemical evaluation, implant-retained overdenture, oral health impact profile, OT-Equator, quality of life, shortened dental arch

How to cite this article:
Alammari MR, Tayel SB. The outcome of in vivo use of Equator attachment systems with implant-supported maxillary overdenture on patients’ satisfaction and biochemical measuring of MMP-8. Int J Oral Care Res 2018;6:21-6

How to cite this URL:
Alammari MR, Tayel SB. The outcome of in vivo use of Equator attachment systems with implant-supported maxillary overdenture on patients’ satisfaction and biochemical measuring of MMP-8. Int J Oral Care Res [serial online] 2018 [cited 2023 Mar 25];6:21-6. Available from: https://www.ijocr.org/text.asp?2018/6/3/21/250271

  Introduction Top

A functional dentition is necessary for biological and social functions and aesthetics. The shortened dental arch concept (SDAC) is based on a person requiring a minimum number of natural teeth, usually cited as 20, to have adequate dental function.[1],[2] Despite care from dental professionals and increased level of dental awareness, teeth can be lost or damaged leading to a reduction in the number of occlusal units.[3],[4],[5]

The shortened dental arch (SDA) has been described as a minimum of four occlusal units, which provide functional satisfaction to older adults with sufficient adaptive capacity.[6] It is a problem-based treatment approach that meets the functional, biological, social, and psychological needs of the older dental patients to an acceptable level and potentially reduces the costs of treatment.[7],[8] Elder individuals with a reduced dentition of four intact premolars and one occluding pair of molars have adequate masticatory function. In addition, they are able to maintain satisfactory levels of occlusal stability.[9],[10],[11],[12]

The traditional method of replacing missing teeth has been with partial removable dental prostheses (PRDPs). Although patients with perceived impaired function have reported benefits from PRDPs, optimal oral hygiene is required to preserve the remaining dentition.[13],[14],[15]

The use of dental implants over the past 25 years has significantly influenced treatment planning in dentistry. Removable implant-retained overdentures provide easier access for oral hygiene and easy modification of the prosthesis base.[16] There are many different attachments provided by a large number of manufacturers around the world. Most of these are compatible with the majority of the implant systems currently available and are divided into two major categories: bar and stud attachments. Factors taken into consideration while selecting attachment systems are depending on the amount of space available, maintenance requirements, load distribution to the mucosa and to the implants, the degree of retention[17],[18] and clinical experience of the operator.[19]

Lack of bone volume always results in exposure of implant surface, decreased bone–implant interface, and finally implant failure. Unfortunately, the resorption of the alveolar ridges may render the placement of standard-diameter implants difficult or impossible. This can be managed either by surgical correction or by positioning the implant in the area with the greatest available bone or simply using narrow inclined diameter implants.[20]

OT-Equator attachment is considered the smallest with the least overall dimension of any attachment system available. It is designed to provide maximum retention with a low vertical profile of 2.1mm and a diameter of 4.4mm that offers multiple solutions for overdenture treatment planning when vertical space limitations are a consideration. It is indicated to correct divergence up to 28degrees between implants without affecting the functionality of the nylon cap.[21],[22]

Most of the scientific works focusing on peri-implant soft tissue have increased dramatically in the past few years. They examined the morphologic features of epithelium and the connective tissue around implants.[23] Biochemical mediators in the gingival crevicular fluid (GCF) have been identified as potential host marker for periodontal disease activities and progression.[23]

Matrix metalloproteinase-8 (MMP-8), called collagenase-2 or neutrophil collagenase, is an indicator of the breakdown of the extracellular matrix during pathologic process because of its exclusive pattern in the inflammatory condition. It is the key component of peri-implant tissue destruction with peri-implantitis and it exists in elevated amount and in active form in the GCF and peri-implant sulcular fluid (PISF) from progressing periodontitis and peri-implantitis. MMP-8 constitutes of a family of zinc- and calcium-dependent neutral endoproteinases with 28 members (MMP-1 to MMP-28). They play an important role in the normal physiological process such as morphogenesis, reproduction, and tissue remodeling.[24],[25] The conventional method of periodontal indices used for the evaluation of peri-implant soft tissues is unreliable, unfit for clinical evaluation in implant dentistry, and not a clinical marker for bone loss.

Management of the SDA has become a prime concern for dental professionals as an ever-growing proportion of the population seeks to maintain and/or restore oral function into their later years.

Quality of life is pretentious by oral health in the majority of people.[26],[27],[28] The class and quality of prosthetic constructions, and currently more often implant-supported prostheses, can be considered one part of oral health in elderly patients. The oral health impact profile (OHIP-14) index[29],[30],[31] has been used as a shortened 14-item survey to assess the influence of oral health on the quality of life. It measures patients’ perception of the social impact of oral disorders on their well-being. The OHIP-14 captures only negative impacts. However, the OHIP is the most frequently used and best-documented instrument nowadays.[32]

Therefore, the aim of this study was to evaluate the use of SDAC by the placement of implants in risky posterior bone sites in the maxilla adjacent to vital structures and the construction of implant-supported overdenture using biochemical measuring of collagenase-2 (MMP-8) in peri-implant soft tissue and to evaluate the oral health-related quality of life of patients treated with implant-supported maxillary overdentures in Jeddah, Saudi Arabia.

  Materials and Methods Top

This study included 25 dental patients, with a mean age of 62 years, who presented to the Prosthetic Clinic of King Abdulaziz University Dental Hospital with a complaint of edentulous maxillary arch opposed with mandibular class I Kennedy’s classification. All the patients had retruded posterior atrophic edentulous maxilla leaving less than 7mm bone height at the posterior. They were healthy, free from any systemic disease, and with an acceptable level of oral hygiene. Patients with temporomandibular or neuromuscular disorders were excluded.

The study was reviewed and approved by the research ethics committee at the Faculty of Dentistry, King Abdulaziz University (REC-2016/056). Patients treated with implant-supported maxillary overdentures between 2016 and 2018 were considered for this study. They were referred to the Prosthodontics Department in King Abdulaziz University Dental Hospital as being very challenging cases. Main signs for implant treatment of these patients were severe retention problems of conventional prostheses, recurrent mucosal pain and sore spots, and problems with chewing related to advanced alveolar bone resorption. Accordingly, they were treated with implant-supported maxillary overdentures between 2016 and 2018.

Preoperative dental panoramic tomography revealed unfavorable vertical heights of the maxillary edentulous ridges because of insufficient alveolar bone quantity, particularly in the dorsal parts of the maxilla that compromised the possibility of inserting implants in the upper molar regions. The study design was explained to the patients and the possible complications. Accordingly, the decision was to use SDAC in the form of implant-supported horseshoe maxillary overdenture and mandibular removable partial denture (RPD) with restoring second premolars.

Routine laboratory and medical investigations were performed for the patients undergoing implant surgery. The mounted diagnostic cast was duplicated and diagnostic wax-up was fabricated to identify the ideal implant position.

An acrylic horse shoe complete denture was fabricated for each patient using conventional standard technique.[33] Radiographic surgical stent was fabricated from clear heat acrylic replica of the prefabricated denture.

The patients received six endosseous titanium implants (Superline, Dentium Co., Ltd, Seoul, Korea) in the maxillary arch, two in the anterior area place axially with 8-mm length and two at posterior area in both right and left with 10-mm length and 3.6mm width [Figure 1A].{Figure 1A}

All the steps of implant placement were achieved according to the manufacturer’s instructions. The surgical procedure was performed in two steps. First, surgical mucoperiosteal flap was made for the placement of the implant fixture at the prepared site and covered with cover screws. The patients were not allowed to wear their denture for the first two postoperative weeks.

After 2 weeks, the conventional horseshoe maxillary denture was used and relined with soft lining material (Coe-Soft; GC America, Inc, Alsip, Ill), with the appropriate thickness to ensure adequate relief over the implant tissues. The patients were allowed to use dentures. Clinical and radiographic (panoramic and periapical radiographs) evaluations were performed to ensure implant integration.

The second-stage surgery was performed 4 months after healing. The implants were uncovered by small crestal incisions at the location of the implants. The cover screws were removed and the healing abutments were placed for 1 week and then removed to measure the cuff height to select the correct low-profile attachment. The OT-Equator was secured in the implant [Figure 1B]. The OT-Equator attachments implant–assisted overdenture (Rhein83, Bologna, Italy) was incorporated to the maxillary horseshoe denture by direct pick-up technique. The orientation of the attachment inside the denture base was examined. Smoothing and polishing the surface of the denture base were carried out and then occlusal equilibration with mandibular RPD was completed.

Biochemical evaluation

MMP-8 (collagenase-2) was determined in PISF using Sandwich Enzyme Immunoassay Quantikine enzymelinked immunosorbent assay (ELISA) (R&D Systems, Minneapolis, MN).[34]

Sample collection of sulcular fluid:

The surface of the implants was dried gently with air and kept dry with cotton wool rolls placed into the buccal, labial vestibule, and lingual pouch of the oral cavity. The filter strip was picked up with sterile tweezers and placed gently in the opening of the peri-implant margin 1mm into the sulcus and left for 4min.

The fluid absorbed by the strip was eluted in 50 µL of 50mM Tris-HCl (pH, 7.5), 0.15 M NaCl, and 1mM CaCl2. The elute was then centrifuged and aliquots of supernatants were stored at -20°C until assayed for MMP-8.

Patient-based assessment

The OHIP index (OHIP-14)[27] was used as a shortened 14-item questionnaire to evaluate the impact of oral health on the quality of life. The index measures people’s perception of the social effect of oral disorders on their well-being.

Opinions regarding their treatment were evaluated by oral health–related quality of life (OHIP). The OHIP-14 included seven domains: functional limitation, physical discomfort, psychological discomfort, physical disability, psychological disability, social disability, and handicap [Table1]. The patients were asked to fill out a validated questionnaire at the insertion and after 3 months of insertion of implant-supported SDA overdenture. Each questionnaire item was rated on a five-point Likert-format scale, which ranged from 0 = never, 1 = hardly, 2 = occasionally, 3 = fairly often, to 4 = very often. For each of the seven domains of the questionnaire, the mean value for each domain was calculated by summing the mean values assigned to the questions.{Table1}

Statistical method

The Statistical Package for the Social Sciences software (version 23.0; SPSS, Chicago, IL) was used to perform the statistical analyses of the data. Descriptive statistics as mean and standard deviation were used. Analysis of variance test with repeated measures was used to compare between before and after implant placement and the subsequent follow-up periods. Significance level between different periods of time was tested using post hoc test (Bonferroni). The average values of the OHIP-14 score were calculated and the results were analyzed using Student’s t-test. A significant level of P < 0.05 was used.

  Results Top

The mean value and standard deviation of estimation collagenase-2 or MMP-8 in the PISF 4 weeks, 6, and 9 months after implant placement are shown in [Table 2]. A statistically significant difference was observed between different periods (4 weeks, 6th, and 9th months) at 5% level (F = 56.649). Comparison between different periods revealed a statistically significant decrease (P1 = 0.012, P2 = 0.004, P3 < 0.001).
Table 2: Measurement of collagenase-2 (MMP-8), (ng/mL)

Click here to view

[Table 3] presents the mean score values and standard deviation for the OHIP-14 questionnaire at the denture insertion (pre-OHIP) and after 6 months (post-OHIP) of insertion of implant-supported overdenture. All the domains showed a statistically significant improvement at 5% level except domains regarding social disability and handicap, which showed no significant improvement.
Table 3: Mean scores of the different domains of oral health impact profile (OHIP-14) at insertion and after 6 months of denture insertion

Click here to view

  Discussion Top

The Oral Health Impact Profile (OHIP) is an indicator in the diagnosis; treatment planning, and also the treatment benefits to patients. This indicator was applied by means of interview to assure understanding and enhance differentiation among possible responses.[29],[30],[31]

Giving to the results of the present study, it can be perceived that patients treated with implant-supported maxillary overdentures were satisfied with the result of the treatment when evaluated using the OHIP-14 questionnaire. Results showed general improvement in overall quality of life of patients as compared to pre-OHIP. This may be attributed to satisfaction with their ability to chew and enjoy the meals they often labor to chew.[30],[31]

Patients were more satisfied with short implant and implant-supported SDA overdenture meaning that the addition of short implant did significantly improve the overall quality of the construction. The oral health related to quality of life is highly correlated with the quality of the prosthesis, suggesting that a denture of poor quality, which is replaced by a technically optimized one will improve acceptance and satisfaction.[36],[37] The short implant placement with OT-Equator in the posterior region became available as an alternative treatment modality to bone-grafting procedures to provide implant support to a removable partial denture or fixed partial dentures in the resorbed posterior regions.[37],[38]

Biochemical marker of collagenase-2 level (MMP-8) in PISF was chosen to evaluate the condition of peri-implant tissues and assess implant success. The biochemical marker was selected due to its specificity and accuracy.[25] Our results revealed a highest amount of collagenase-2 after 4 weeks of implant placement, which might be due to the active phase of bone and soft tissue remodeling that appeared after implant placement. Collagenase-2 level in the PISF significantly decreased after 6 and 9 months of follow-up periods. This results might be related to the decrease in the amount of bone loss and improved oral hygiene.[39]

  Conclusion Top

This study has evident shortcomings partly because of the relatively small patient groups who participated in the examination. It has been well known that tooth loss and complete edentulism will remain a reality in old, aging population. On the basis of the results of this study, it could be stated that overdenture treatment with implants and OT-Equator attachments might be the treatment option of the future as it is easier, economical, and has a great impact on patients’ satisfaction. Biochemical analysis of collagenase-2 (MMP-8) was a potential host marker for the condition of peri-implant tissue as it could prevent failure of dental implant, and was considered as a problem-solving approach to avoid surgical complications near vital structure.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Koltermann AP, Giordani JM, Pattussi MP. The association between individual and contextual factors and functional dentition status among adults in Rio Grande do Sul State, Brazil: A multilevel study. Cad Saude Publica 2011;27:173-82.  Back to cited text no. 1
Thorstensson H, Johansson B. Why do some people lose teeth across their lifespan whereas others retain a functional dentition into very old age? Gerodontology 2010;27:19-25.  Back to cited text no. 2
McCord JF, Grant AA, Youngson CC, Watson RM, Davis DM. Missing Teeth. A Guide to Treatment Options. Edinburgh, Scotland: Churchill Livingstone; 2003.  Back to cited text no. 3
Kayser AF, Witter DJ. Oral functional needs and its consequences for dentulous older people. Community Dent Health 1985;2:285-91.  Back to cited text no. 4
Armellini D, von Fraunhofer JA. The shortened dental arch: A review of the literature. J Prosthet Dent 2004;92:531-5.  Back to cited text no. 5
Hultin M, Davidson T, Gynther G, Helgesson G, Jemt T, Lekholm U, et al. Oral rehabilitation of tooth loss: A systematic review of quantitative studies of OHRQoL. Int J Prosthodont 2012;25:543-52.  Back to cited text no. 6
Barsby MJ, Hellyer PH, Schwarz WD. The qualitative assessment of complete dentures produced by commercial dental laboratories. Br Dent J 1995;179:51-7.  Back to cited text no. 7
Kanno T, Carlsson GE. A review of the shortened dental arch concept focusing on the work by the Kayser/Nijmegen group. J Oral Rehabil 2006;33:850-62.  Back to cited text no. 8
Sarita PTN. The shortened dental arch concept and its relevance for oral health care in developing countries. Int J Contemp Dent 2012;3:89-95.  Back to cited text no. 9
Wolfart S, Muller F, Gerb J, Heyedcke G, Marré B, Böning K, et al. The randomized shortened dental arch study: Oral health-related quality of life. Clin Oral Investig 2014;18:525-33.  Back to cited text no. 10
McKenna G, Allen F, Woods N, O'Mahony D, Cronin M, DaMata C, et al. Cost effectiveness of tooth replacement strategies for partially dentate elderly: A randomized controlled clinical trial. Community Dent Oral Epidemiol 2014;42:366-74.  Back to cited text no. 11
Witter DJ, Creugers NHJ, Kreulen CM, de Haan AFJ. Occlusal stability in shortened dental arches. J Dent Res 2001;80:432-6.  Back to cited text no. 12
Kayser AF, Witter DJ, Spanauf AJ. Overtreatment with removable partial denture in shortened dental arches. Aust Dent J 1987;32:178-82.  Back to cited text no. 13
Demirbuga S, Tuncay O, Cantekin K, Cayabatmaz M, Dincer AN, Kilinc HI, et al. Frequency and distribution of early tooth loss and endodontic treatment needs of permanent first molars in a Turkish pediatric population. Eur J Dent 2013;7:S99-104.  Back to cited text no. 14
Sarita PT, Kreulen CM, Witter DJ, van’t Hof M, Creugers NH. A study on occlusal stability in shortened dental arches. Int J Prosthodont 2003;16:375-80.  Back to cited text no. 15
Abuzar MA, Humplik AJ, Shahim N. The shortened dental arch concept: Awareness and opinion of dentists in Victoria, Australia. Aust Dent J 2015;60:294-300.  Back to cited text no. 16
El-Anwar M, Mohammed SM. Comparison between two low profile attachments for implant mandibular overdentures. J Genet Eng Biotechnol 2014;12:45-53.  Back to cited text no. 17
Ahuja S, Cagna DR. Defining available restorative space for implant overdentures. J Prosthet Dent 2010;104:133-136.  Back to cited text no. 18
Andreiotelli M, Att W, Strub JR. Prosthodontic complications with implant overdentures: A systematic literature review. Int J Prosthodont 2010;23:195-203.  Back to cited text no. 19
Trakas T, Michalakis K, Kang K, Hirayama H. Attachment Systems for Implant Retained Overdentures: A literature Review. Implant Dent 2006;15:24-34.  Back to cited text no. 20
Koc D, Dogan A, Bek B. Bite force and influential factors on bite force measurements: A literature review. Eur J Dent 2010; 4: 223-32.  Back to cited text no. 21
Ibrahim A. Equator versus Locator as attachment for implant supported overdenture. Master Thesis, Faculty of dentistry, Ain Shams University 2013.  Back to cited text no. 22
Rizk F. Comparative study of OT-Equator profile attachment versus GPS attachment in implant retained mandibular overdenture case. Egypt Dent J 2012;58:65-9.  Back to cited text no. 23
Verhoeven JW, Cune MS, de Putter C. Reliability of some clinical parameter of evaluation in implant dentistry. J oral Rehabil 2000;27:211-216.  Back to cited text no. 24
Ma J, Kitti U, Teronen O, Sorsa T, Husa V, Laine P, et al. Collagenases in different categories of peri-implant vertical bone loss. J Dent Res 2000;79:1870-3.  Back to cited text no. 25
Siadat H, Alikhasi M, Mirfazaelian A,Geramipanah F, Zaery F. Patient satisfaction with implant-retained mandibular overdentures: A retrospective study. Clin Implant Dent Relat Res 2008;10:93-8.  Back to cited text no. 26
Slade GD. Derivation and validation of a short-form oral health impact profile. Community Dent Oral Epidemiol 1997 25:284-90.  Back to cited text no. 27
Strassburger C, Heydecke G, Kerschbaum T. Influence of prosthetic and implant therapy on satisfaction and quality of life: A systematic literature review. Part 1-Charasteristics of the studies. Int J Prosthodont 2004;17:83-93.  Back to cited text no. 28
Hadzipasic-Nazdrajic A. Quality of life with removable dentures. Mater Sociomed 2011;23:214-20.  Back to cited text no. 29
Locker D, Allen FP: What do measures of ‘oral health-related quality of life’ measure? Community Dent Oral Epidemiol 2007;35: 401-411.  Back to cited text no. 30
Locker D, Gibson B: The concept of positive health: A review and commentary on its application in oral health research. Community Dent Oral Epidemiol 2006;34:161-173.  Back to cited text no. 31
Omo OJ, Sede MA, Esan TA. Quality of life in subjects with shortened dental arch rehabilitated with removable metal-based partial denturesEur J Prosthodont 2016;5:25-31.  Back to cited text no. 32
Inukai M, Baba K, John MT, Igarashi Y.Does removable partial denture quality affect individuals’ oral health, J Dent Res 2008;87: 736-739.  Back to cited text no. 33
Ingman T, Kononen M, Konttinen YT, Siirila HS, Suomalaninen K, Sorsa T. Collagenase, Gelatinase and Elastase activities in sulcular fluid of osseointegrated implants and natural teeth. J Clin Periodontol 1994;21:301-307.  Back to cited text no. 34
Turker SB, Sener ID, Ozkan YK. Satisfaction of the complete denture wearers related to various factors. Arch GerontolGeriatr 2009;49:e126-9.  Back to cited text no. 35
Jensen Ch, Raghoebar GM, Meijer HJ, Schepers R, Cune MS. Comparing two diagnostic procedures in planning dental implants to support a mandibular free-ending removable partial denture Clin Implant Dent Relat Res 2015.  Back to cited text no. 36
Goene R, Bianchesi C, Huerzeler M, Del Lupo R, Testori T, Davarpanah M et al. Performance of short implants in partial restorations: 3-year follow-up of Osseotite implants. Implant Dent 2005;14:274-80.  Back to cited text no. 37
Morand M, Irinakis T. The challenge of implant therapy in the posterior maxilla: Providing a rationale for the use of short implants.J Oral Implantol 2007;33:257-66.  Back to cited text no. 38
Ma Jian. Adverse host tissue responses in loosening of dental implants: Proteolytic enzymes and peri-implant tissue destruction. Academic Dissertation. Helisinki2004;47. ISBN 952-91-6889-6 (paper).  Back to cited text no. 39


  [Figure 1]

  [Table 1], [Table 2], [Table 3]


    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

  In this article
   Materials and Me...
   Article Figures
   Article Tables

 Article Access Statistics
    PDF Downloaded361    
    Comments [Add]    

Recommend this journal