Medical knowledge | Dentistry » Christopher-Finbarr - Overcoming the unstable mandibular complete denture, The neutral zone impression technique

2EMOVABLE0ROSTHODONTICS #HRISTOPHER $ ,YNCH 0 &INBARR !LLEN /VERCOMING THE 5NSTABLE -ANDIBULAR #OMPLETE $ENTURE 4HE .EUTRAL :ONE )MPRESSION 4ECHNIQUE !BSTRACT 4HIS ARTICLE DESCRIBES A TECHNIQUE FOR IMPROVING THE STABILITY OF MANDIBULAR COMPLETE DENTURES FOR PATIENTS WHO HAVE A DIMINISHED MANDIBULAR NEUTRAL ZONE 4HE TECHNIQUE INVOLVES MAKING AN IMPRESSION WHICH IS SHAPED BY THE PATIENTS ORAL MUSCULATURE AND WHICH DEFINES THE SHAPE AND CONTOUR OF THE PATIENTS NEUTRAL ZONE ! CASE REPORT IS PRESENTED IN WHICH THE USE OF THIS TECHNIQUE IS DESCRIBED )T IS HOPED THAT THIS ARTICLE WILL INCREASE THE AWARENESS OF DENTAL PRACTITIONERS TO THE USE OF THIS TECHNIQUE #LINICAL 2ELEVANCE 4HE NEUTRAL ZONE IMPRESSION TECHNIQUE IS A USEFUL TECHNIQUE WHEN PROVIDING MANDIBULAR COMPLETE DENTURES )TS USE CAN OVERCOME SOME OF THE DENTURE STABILITY DIFFICULTIES CAUSED IN SOME PATIENTS BY A MORE POWERFUL ORAL MUSCULATURE OR IN PATIENTS WHO HAVE POOR OR ALTERED NEUROMUSCULAR CONTROL $ENT 5PDATE

    !S A RESULT OF RECENT ADVANCES IN DENTAL TREATMENTS AND INCREASED UTILIZATION OF DENTAL SERVICES BY THE PUBLIC THERE HAS BEEN A FALL IN THE PREVALENCE OF EDENTULOUSNESS 4HIS DEVELOPMENT HAS RESULTED IN A DENTAL POPULATION WHO BECOME EDENTULOUS LATER IN LIFE IF AT ALL AND IN WHOM THERE MAY BE DIMINISHED NEUROMUSCULAR CONTROL TO ADAPT TO COMPLETE DENTURES !NOTHER CONSEQUENCE OF THIS ADVANCE IN DENTAL PROFILE IN SOCIETY IS DECREASED EXPOSURE OF DENTAL STUDENTS AND DENTAL PRACTITIONERS TO THE CHALLENGES OF COMPLETE DENTURE #HRISTOPHER $ ,YNCH "$3 -&$ 2#3) 2EGISTRAR IN 2ESTORATIVE $ENTISTRY AND 0 &INBARR !LLEN "$3 -3C &$3 2#03 0H$ $EPARTMENT OF 2ESTORATIVE $ENTISTRY .ATIONAL 5NIVERSITY OF )RELAND #ORK )RELAND *ANUARY&EBRUARY  PROSTHODONTICS /NE SUCH CHALLENGE IS THE UNSTABLE MANDIBULAR COMPLETE DENTURE !N UNSTABLE MANDIBULAR COMPLETE DENTURE MAY OCCUR FOR A VARIETY OF REASONS „ )NCORRECT EXTENSIONS OF BUCCAL OR LINGUAL FLANGES „

0OORLY ADAPTED FITTING SURFACE „ !N ATROPHIC MANDIBULAR RIDGE OR „ !N INAPPROPRIATELY CONTOURED POLISHED SURFACE 3OME PATIENTS HAVE DIMINISHED OR ALTERED NEUROMUSCULAR CONTROL SUCH AS THOSE WHO HAVE 0ARKINSONS DISEASE OR THOSE WHO HAVE HAD A STROKE OR SURGICAL RESECTION 4HE FOCUS OF THIS PAPER IS ON THE MANDIBULAR COMPLETE DENTURE THAT FITS WELL AND IS PROPERLY EXTENDED BUT IS STILL @LOOSE 4HIS PROBLEM IS CAUSED BY POOR OR INAPPROPRIATE CONTOUR OF THE POLISHED SURFACES OR POSITIONING OF THE TEETH ON THE MANDIBULAR COMPLETE DENTURE )T WILL BE RECALLED THAT THERE IS A ZONE OF @MINIMAL CONFLICT BETWEEN THE BUCCAL AND LINGUAL MUSCULATURE WITHIN WHICH A DENTURE SHOULD OPTIMALLY BE SITUATED 4HIS ZONE OF @MINIMAL CONFLICT IS ALSO REFERRED TO AS THE @NEUTRAL ZONE  OR @DENTURE SPACE &IGURE   4HE POLISHED SURFACES OF A MANDIBULAR DENTURE SHOULD BE CONTOURED SUCH THAT THEY DO NOT ENCROACH ON THE LINGUAL OR BUCCAL MUSCULATURE DURING FUNCTION n TO DO SO WOULD RESULT IN A

FORCE BEING APPLIED TO THE DENTURE THAT WOULD RESULT IN ITS DISPLACEMENT (OWEVER IN SOME PATIENTS THE EXTENT OF THE NEUTRAL ZONE MAY BE LIMITED 4HERE HAS BEEN MUCH FOCUS IN RECENT TIMES ON THE @TRANSITION TO THE EDENTULOUS STATE ! POORLY PLANNED TRANSITION CHARACTERIZED BY UNCONTROLLED TOOTH EXTRACTION CAN LEAD TO „ ,ATERAL SPREADING OF THE TONGUE IN THE POSTERIOR PART OF THE MOUTH „ %XCESSIVE ANTERIOR RESORPTION LEADING $ENTAL5PDATE  2EMOVABLE0ROSTHODONTICS &IGURE  $IAGRAMMATIC REPRESENTATION OF THE @NEUTRAL ZONE &ORCES ARE APPLIED TO THE DENTURE BASES BY THE CHEEK AND THE TONGUE &OR OPTIMAL STABILITY AND RETENTION COMPLETE DENTURES SHOULD BE SITUATED IN THE @NEUTRAL ZONE WHERE SUCH FORCES @CANCEL EACH OTHER &IGURE DRAWN BY -S #ATHERINE -ACILLYCUDDY AND 2ICHARD 4AYLOR TO INCREASED PROMINENCE OF THE MENTALIS MUSCLE )N SUCH PATIENTS THE SIZE OF THE NEUTRAL ZONE MAY BE DRASTICALLY REDUCED )N SOME PATIENTS THE SHAPE OF THE NEUTRAL ZONE IS MORE

gBIZARREg FOR EXAMPLE FOLLOWING A SURGICAL RESECTION A STROKE SCLERODERMA OR ARISING FROM OTHER NATURAL CAUSES SUCH AS A PROMINENT MENTAL GROOVE 4HE PURPOSE OF THIS PAPER IS TO DESCRIBE AN IMPRESSION TECHNIQUE FOR RECORDING THE NEUTRAL ZONE FOR MANDIBULAR COMPLETE DENTURES 4HIS TECHNIQUE HAS BEEN REFERRED TO IN THE PAST AS THE gANTHROPOIDAL POUCH TECHNIQUEg  @MUSCLE FORMED MANDIBULAR DENTURE TECHNIQUE  OR @DENTURE FORM IMPRESSION TECHNIQUE &IGURE %XTRA ORAL PHOTOGRAPH OF THE PATIENT PRIOR TO TREATMENT .OTE THE LIMITED MOUTH OPENING AND @TIGHTNESS OF ORAL MUSCULATURE WAS WELL RETAINED AND AFTER DISCUSSION WITH THE PATIENT IT WAS DECIDED TO RETAIN THIS PROSTHESIS /N EXAMINATION OF THE MANDIBULAR DENTURE BEARING AREA IT WAS NOTED THAT THERE HAD BEEN LATERAL SPREADING OF THE PATIENTS TONGUE AND THAT THE NEUTRAL ZONE WAS DIMINISHED )T WAS DECIDED TO PROVIDE THE PATIENT WITH A MANDIBULAR COMPLETE DENTURE UTILIZING A NEUTRAL ZONE IMPRESSION TECHNIQUE 4REATMENT FOR THIS

PATIENT IS OUTLINED UNDER THE HEADING OF THE VARIOUS CLINICAL AND LABORATORY VISITS #LINICAL VISIT  ! PRIMARY IMPRESSION WAS MADE OF THE PATIENTS EDENTULOUS RIDGE USING A PLASTIC STOCK TRAY AND ALGINATE !LGINATE $ENTSPLY ,TD 5+ 7EYBRIDGE 3URREY 5+  4HE PLASTIC STOCK TRAY HAD BEEN MODIFIED AS A RESULT OF THE PATIENTS MICROSTOMIA THE ENDS OF THE TRAY WERE REMOVED  #LINICAL REPORT !  YEAR OLD FEMALE PATIENT WAS REFERRED TO THE $EPARTMENT OF 2ESTORATIVE $ENTISTRY 5NIVERSITY $ENTAL 3CHOOL AND (OSPITAL 7ILTON #ORK )RELAND FOR PROVISION OF A MANDIBULAR COMPLETE DENTURE &IGURE   4HE PATIENT HAD BEEN EDENTULOUS FOR  YEARS AND WHILE SHE HAD BEEN ABLE TO WEAR A MAXILLARY PROSTHESIS WAS UNABLE TO WEAR A MANDIBULAR COMPLETE DENTURE 4HE PATIENT REPORTED THAT THE LACK OF A MANDIBULAR PROSTHESIS HAD A NEGATIVE EFFECT ON HER QUALITY OF LIFE AS SHE WAS CONSCIOUS OF HER SPEECH AND HER ABILITY TO EAT IN PUBLIC /N EXAMINATION OF THE PATIENT IT WAS FOUND THAT SHE HAD MICROSTOMIA AND

MAXILLARY HYPOPLASIA (ER MAXILLARY COMPLETE DENTURE  $ENTAL5PDATE &IGURE  -ANDIBULAR OCCLUSAL RIM SHAPED TO AN APPROXIMATE BUCCO LINGUAL DIMENSION #LINICAL VISIT  4HE ACRYLIC BASEPLATE WAS RETURNED TO THE CHAIRSIDE AND TRIED IN THE MOUTH 4HE RETENTION STABILITY AND EXTENSIONS WERE ASSESSED 4HE USE OF A TRANSPARENT MATERIAL ALLOWED VISUALIZATION OF THE ADAPTATION OF THE BASEPLATE TO THE DENTURE BEARING AREA ! WAX BLOCK WAS ADDED TO THE BASEPLATE AND A @CONVENTIONAL OCCLUSAL REGISTRATION VISIT TOOK PLACE 4HE POLISHED SURFACES OF THE WAX BLOCK WERE CONTOURED AS CLOSE TO THE SHAPE OF THE NEUTRAL ZONE AS POSSIBLE &IGURE  AND THE HEIGHT OF THE WAX BLOCK WAS ADJUSTED TO PERMIT AN ACCEPTABLE OCCLUSO VERTICAL DIMENSION /6$ IE THE FREE WAY SPACE WAS  MM 4HE REASON FOR MAKING THE BASEPLATE ALONE FIRST WAS TO PERMIT AN ASSESSMENT OF ITS ACCURACY n A CONCERN FOLLOWING THE DIFFICULTY IN MAKING A MASTER IMPRESSION ! FACE BOW TRANSFER AND CENTRIC RELATION WERE RECORDED

6ISIT  LABORATORY 6ISIT  LABORATORY ! PRIMARY MODEL WAS POURED FROM THIS IMPRESSION AND AN ACRYLIC SPECIAL TRAY WITH  MM SPACING WAS FABRICATED #LINICAL VISIT  4HE EXTENSIONS OF THE SPECIAL TRAY WERE ASSESSED INTRA ORALLY ! SECONDARY IMPRESSION WAS MADE USING POLYVINYLSILOXANE %XTRUDE +ERR #ORPORATION 2OMULUS -)  6ISIT  LABORATORY ! TRANSPARENT HEAT CURED ACRYLIC BASEPLATE WAS MADE ON THE MASTER CAST )N THE LABORATORY THE MAXILLARY CAST WAS MOUNTED ON A SEMI ADJUSTABLE ARTICULATOR $ENAR !NAMARK &OSSAE 4ELEDYNE 7ATER 0IK &ORT #OLLINS #OLORADO 53! USING THE FACE BOW TRANSFER 4HE MANDIBULAR CAST WAS LOCATED TO THE UPPER AT THE CORRECT /6$ AND IN #ENTRIC 2ELATION USING THE MANDIBULAR WAX BLOCK 4HE WAX BLOCK WAS REMOVED AND WAS REPLACED WITH VERTICAL WIRE LOOPS WHICH WERE ATTACHED TO THE TRANSPARENT ACRYLIC BASE 4HESE WERE CAREFULLY POSITIONED WITHIN THE BUCCO LINGUAL DIMENSION AS DEFINED BY THE CONTOURS OF THE WAX BLOCK AND CONFORMED TO THE SAME /6$ AS THE

HEIGHT OF THE WAX BLOCK &IGURE   *ANUARY&EBRUARY  2EMOVABLE0ROSTHODONTICS &IGURE  -ANDIBULAR BASEPLATE WITH VERTICAL WIRE LOOPS ATTACHED &IGURE  )NTRA ORAL VIEW OF BASEPLATE AND WIRE LOOPS .OTE THE BUCCO LINGUAL LOCATION OF THESE A B &IGURE  A )NTRA ORAL VIEW OF COMPLETED NEUTRAL ZONE IMPRESSION B %XTRA ORAL VIEW OF COMPLETED NEUTRAL ZONE IMPRESSION A B &IGURE  !PPLICATION OF TISSUE CONDITIONING AGENT TO THE WIRE LOOPS HER LIPS CHEEKS AND TONGUE SWALLOWING CHEWING@PUFFING OF CHEEKS AND @SUCKING IN OF LIPS WHILST KEEPING THE RIMS IN OCCLUSAL CONTACT 4HIS PERMITTED THE BUCCAL AND LINGUAL ORAL MUSCULATURE TO SHAPE THE TISSUE CONDITIONING AGENT ON THE WIRE LOOPS TO THE CONTOURS OF THE NEUTRAL ZONE &IGURE A  4HE PATIENT WAS LEFT TO PERFORM THESE ACTIONS FOR UP TO  MINUTES !FTER THIS TIME THE BASEPLATE AND ATTACHED MATERIALS WERE REMOVED DISINFECTED IN THE NORMAL WAY AND RETURNED TO THE LABORATORY &IGURE B 

6ISIT  LABORATORY &IGURE  A B 0UTTY INDICES APPLIED TO COMPLETED NEUTRAL ZONE IMPRESSION #LINICAL VISIT  &IGURE  4EETH SET UP FOR TRY IN USING PUTTY INDICES  $ENTAL5PDATE !T THE CHAIRSIDE THIS APPLIANCE WAS ASSESSED TO ENSURE THE BASEPLATE WAS NOT OVEREXTENDED AND THAT THE WIRE LOOPS WERE IN THE CORRECT BUCCO LINGUAL POSITION &IGURE   4HE FREE WAY SPACE WAS ASSESSED TO ENSURE THAT THE HEIGHT OF THE WIRE LOOPS WAS NOT DIFFERENT FROM THE HEIGHT OF THE WAX BLOCK 4ISSUE CONDITIONING MATERIAL #OE 3OFT 2ESILIENT $ENTURE ,INER # !MERICA )NC !LSIP ), 53! WAS APPLIED TO THE WIRE LOOPS &IGURE  AND PLACED IN THE MOUTH 4HE PATIENT WAS INSTRUCTED TO CARRY OUT SIMPLE ORAL MOVEMENTS SUCH AS MOVING )N THE LABORATORY SILICONE PUTTY INDICES #OLTÒNE ,AB 0UTTY #OLTÒNE 7HALEDENT MB( +ONSTANZ ERMANY OF THE BASEPLATE AND ATTACHED MATERIALS WERE MADE &IGURE A B  4HE TISSUE CONDITIONING MATERIAL AND WIRE LOOPS WERE REMOVED AND USING THE SILICONE PUTTY

INDICES REPLACED WITH PROSTHETIC TEETH &IGURE   4HE BUCCO LINGUAL WIDTH OF THESE TEETH WAS DETERMINED BY THE CONTOUR OF THE BUCCAL AND LINGUAL MUSCULATURE RECORDED ON THE TISSUE CONDITIONING MATERIAL !S THE STABILITY OF THE PLANNED MANDIBULAR COMPLETE DENTURE WAS A CONCERN SHALLOW ANGLED CUSPED POSTERIOR PROSTHETIC TEETH WERE ARRANGED ON A SEMI ADJUSTABLE ARTICULATOR IN BALANCED ARTICULATION !S THIS PATIENT HAD A #LASS ))) 3KELETAL "ASE THE LOWER ANTERIOR TEETH WERE RETROCLINED TO RESEMBLE A #LASS ) INCISOR RELATIONSHIP HOWEVER IT WAS NOT POSSIBLE TO POSITION THESE LINGUAL TO THE CONTOUR MADE BY THE TONGUE ON THE ANTERIOR SECTION OF THE TISSUE CONDITIONING AGENT 4HIS WAS RETURNED TO THE CHAIRSIDE AS A @CONVENTIONAL TRY IN &IGURE   *ANUARY&EBRUARY  2EMOVABLE0ROSTHODONTICS &IGURE  4EETH SET UP FOR TRY IN ON SEMI ADJUSTABLE ARTICULATOR .OTE THE RETROCLINATION OF THE MANDIBULAR ANTERIOR TEETH &IGURE  4HE COMPLETED DENTURE #LINICAL

VISIT  !T THE CHAIRSIDE @TRY IN TOOK PLACE 4HE STABILITY AND RETENTION OF THE PROSTHESIS WAS ASSESSED AND FOUND TO BE SATISFACTORY 4HE PATIENT WAS SATISFIED WITH THE APPEARANCE OF THE LOWER ANTERIOR TEETH EVEN THOUGH THERE WAS A @REVERSE OVERJET  4HE TRY IN WAS RETURNED TO THE LABORATORY 6ISIT  LABORATORY 4HE DENTURE WAS PROCESSED IN THE NORMAL MANNER #LINICAL VISIT  4HE MANDIBULAR COMPLETE DENTURE WAS RETURNED TO THE CHAIRSIDE AND WAS FOUND TO BE SATISFACTORY IN TERMS OF STABILITY RETENTION AESTHETICS AND OCCLUSION &IGURE   !T SUBSEQUENT REVIEW APPOINTMENTS THE PATIENT REPORTED SATISFACTION WITH THE PROSTHESIS $ISCUSSION )T IS OFTEN MORE CLINICALLY CHALLENGING TO PROVIDE A MANDIBULAR COMPLETE DENTURE THAN A MAXILLARY ONE *ANUARY&EBRUARY  )T IS EVEN MORE SO WHEN THERE IS ALTERED NEUROMUSCULAR CONTROL OR WHEN THE NEUTRAL ZONE HAS BEEN ALTERED AS A RESULT OF SURGICAL RESECTION OR WHERE THERE ARE POWERFUL LINGUAL OR BUCCAL MUSCLES 7HILE DENTAL IMPLANTS

ARE A POSSIBLE TREATMENT OPTION IN THIS SITUATION THERE IS A GROUP OF PATIENTS WHO FOR A VARIETY OF CLINICAL OR MEDICAL REASONS ARE UNSUITED FOR DENTAL IMPLANT TREATMENT 4HERE ARE ALSO SOME PATIENTS WHO DO NOT WISH TO HAVE SURGICALLY INVASIVE PROCEDURES SUCH AS THE PLACEMENT OF DENTAL IMPLANTS 4HE TECHNIQUE DESCRIBED PROVIDES A USEFUL WAY TO OVERCOME THIS DIFFICULTY )T IS ALSO INDICATED WHEN A MANDIBULAR DENTURE IS @LOOSE BUT APPEARS TECHNICALLY CORRECT IE CORRECTLY EXTENDED AND WELL ADAPTED TO THE DENTURE BEARING AREAS  4HE CLINICIAN SHOULD AVOID ATTEMPTING TO CORRECT THIS PROBLEM BY @RE LINING THE DENTURE 4HE INSTABILITY IS NOT CAUSED BY POOR FIT BUT INAPPROPRIATE CONTOUR OF THE POLISHED SURFACES )T MAY ALSO BE APPRECIATED THAT IN PATIENTS WHERE THE DENTURE BEARING AREAS ARE LESS THAN IDEAL EG A MARKEDLY RESORBED RIDGE OR IN PATIENTS WITH ALTERED NEUTRAL ZONES AS A RESULT OF STROKE OR SURGICAL RESECTION POLISHED SURFACES THAT ARE CONTOURED TO MATCH THE SHAPE OF THE NEUTRAL

ZONE WILL BE HARNESSED BY THE ORAL MUSCULATURE AND HAVE A POSITIVE EFFECT ON THE RETENTION OF THE MANDIBULAR COMPLETE DENTURE 4HE USE OF WIRE LOOPS AND TISSUE CONDITIONING AGENT TO RECORD THE CONTOURS OF THE NEUTRAL ZONE IS A CLINICAL PREFERENCE OF THE AUTHORS !LTERNATE DESCRIPTIONS IN THE LITERATURE INCLUDE THE USE OF ACRYLIC PILLARS INSTEAD OF WIRE LOOPS   AND THE USE OF WAX  IMPRESSION COMPOUND  CHAIRSIDE RELINING MATERIALS  OR POLYVINYLSILOXANE MATERIALS TO RECORD THE CONTOURS OF THE NEUTRAL ZONE 7HATEVER MATERIALS ARE USED IT SEEMS THAT TWO FACTORS CANNOT BE OVERLOOKED „ 4HE IMPRESSION OF THE NEUTRAL ZONE MUST BE RECORDED AT THE OCCLUSO VERTICAL DIMENSION DETERMINED AT A PREVIOUS VISIT USING AN OCCLUSAL RIM AND „ 4HE MATERIAL SHOULD BE REASONABLY SLOW SETTING TO PERMIT THE ORAL MUSCULATURE TO SHAPE IT TO THE APPROPRIATE CONTOUR AND DIMENSIONS 4HE AUTHORS ALSO ADVOCATE THE USE OF SHALLOW ANGLED CUSPED POSTERIOR PROSTHETIC TEETH AND THEIR ARRANGEMENT ON A BALANCED

ARTICULATION ON A SEMI ADJUSTABLE ARTICULATOR TO REDUCE ECCENTRIC TIPPING FORCES AFFECTING THE PROSTHESIS 4HERE ARE PUBLISHED STUDIES THAT SUPPORT THE USE OF THE NEUTRAL ZONE IMPRESSION TECHNIQUE    )N A STUDY OF 3AUDI !RABIAN PATIENTS &AHMY AND +HARAT FOUND THAT A MAJORITY OF PATIENTS EXPRESSED A PREFERENCE FOR MANDIBULAR COMPLETE DENTURES MADE USING THE NEUTRAL IMPRESSION TECHNIQUE RATHER THAN THOSE MADE IN A @CONVENTIONAL MANNER )N A SIMILAR STUDY IN 3WEDEN "ARRENAS AND /DMAN FOUND THAT A MAJORITY OF PATIENTS AGAIN EXPRESSED A PREFERENCE FOR MANDIBULAR COMPLETE DENTURES MADE USING A NEUTRAL ZONE IMPRESSION ! STUDY BY -ILLER ET AL EXAMINED THE FORCES NECESSARY TO DISLODGE A MANDIBULAR COMPLETE DENTURE ! LARGER FORCE WAS REQUIRED TO REMOVE DENTURES MADE USING A NEUTRAL ZONE IMPRESSION TECHNIQUE THAN A CONVENTIONAL DENTURE .EILL AND LAYSHER EXAMINED THE FORCES EXERTED ON COMPLETE DENTURES IN WHICH THE TEETH WERE ARRANGED USING DIFFERENT METHODS 4HESE

INCLUDED THE USE OF BIOMETRIC GUIDES WHERE THE TEETH ARE ARRANGED RELATIVE TO THE VESTIGE OF LINGUAL GINGIVA AND NEUTRAL ZONE TECHNIQUES 4HEY CONCLUDED THAT WHILE BIOMETRIC GUIDES ARE USEFUL IN CONVENTIONAL COMPLETE DENTURE CASES NEUTRAL ZONE TECHNIQUES ARE INDICATED WHERE THE SITUATION IS LESS STRAIGHTFORWARD !S MENTIONED PREVIOUSLY THE PROBLEM OF A @NARROW NEUTRAL ZONE MAY BE A CONSEQUENCE OF A POORLY PLANNED TRANSITION TO THE EDENTULOUS STATE 4HIS PROBLEM CAN BE AVOIDED IF PROPER CONSIDERATION IS GIVEN TO THIS TRANSITION %XTRACTION OF POSTERIOR TEETH SHOULD BE ACCOMPANIED WITH PROVISION OF A REMOVABLE PARTIAL DENTURE WHERE SUITABLE TO PREVENT LATERAL SPREADING OF THE TONGUE -ANDIBULAR REMOVABLE PARTIAL DENTURES SHOULD BE REVIEWED AND ADJUSTED WHERE NECESSARY TO PREVENT EXCESSIVE ANTERIOR RESORPTION AS THIS CAN LEAD TO INCREASED PROMINENCE OF THE MENTALIS MUSCLE 4HE TRANSITION TO EDENTULOUSNESS SHOULD BE CAREFULLY PLANNED AND MANY OPTIONS ARE CURRENTLY AVAILABLE TO FACILITATE

THIS SUCH AS OVERDENTURES AND TRANSITIONAL PARTIAL DENTURES #ONCLUSION -ANAGEMENT OF AN UNSTABLE MANDIBULAR COMPLETE DENTURE CAN OFTEN BE DIFFICULT AND FRUSTRATING FOR BOTH CLINICIAN AND PATIENT 4HE NEUTRAL ZONE IMPRESSION TECHNIQUE IS A USEFUL WAY OF $ENTAL5PDATE  2EMOVABLE0ROSTHODONTICS OVERCOMING THIS PROBLEM 4HE TECHNIQUE IS ALSO INDICATED WHEN TREATING PATIENTS WITH ALTERED NEUTRAL ZONES AS A RESULT OF STROKE OR SURGICAL RESECTION 4HE ROLE OF PLANNED TRANSITION TO THE EDENTULOUS STATE CANNOT BE UNDERESTIMATED IN AVOIDING THIS PROBLEM !CKNOWLEDGEMENT 4HE AUTHORS THANK -S #ATHERINE -ACILLYCUDDY -! FOR HER DRAWING OF &IGURE  4HE AUTHORS THANK -R 4IM #LARK AND THE STAFF OF THE @$ENTACAST OF %XETER LABORATORY 0/ "OX  " #OWICK 2OAD %XETER %8 "% 5+ FOR THEIR TECHNICAL SUPPORT IN THE CASE DESCRIBED      2EFERENCES  +ELLY - 3TEELE * .UTTALL "RADNOCK -ORRIS * .UNN * 0INE # 0ITTS .  4REASURE % 7HITE $ !DULT $ENTAL

(EALTH 3URVEY n /RAL (EALTH IN THE 5NITED +INGDOM  ,ONDON 4HE 3TATIONERY /FFICE  -ILLER 70 -OTEITH " (EATH -2 4HE EFFECT OF VARIATION OF THE LINGUAL SHAPE OF MANDIBULAR COMPLETE DENTURES ON LINGUAL RESISTANCE TO LIFTING FORCES ERODONTOLOGY   n *AGGER $ (ARRISON ! #OMPLETE $ENTURES n 0ROBLEM 3OLVING ,ONDON "$* "OOKS  &ISH %7 0RINCIPLES OF &ULL $ENTURE 0ROSTHESIS ST ED ,ONDON *OHN "ALE 3ONS  $ANIELSSON  "ASKER 2- $AVENPORT *# 0ROSTHETIC 4REATMENT OF THE %DENTULOUS 0ATIENT TH ED /XFORD "LACKWELL -UNKSGAARD  "ERESIN 6% 3CHIESSER &* 4HE NEUTRAL ZONE IN COMPLETE DENTURES * 0ROSTHET $ENT   n !LLEN 0& 4EETH FOR ,IFE FOR /LDER !DULTS ,ONDON 1UINTESSENCE        7ALSH *& 7ALSH 4 -USCLE FORMED COMPLETE MANDIBULAR DENTURES * 0ROSTHET $ENT   n -C#ORD *& RANT !! )MPRESSION MAKING "R $ENT *   n !LFANO 3

,EUPOLD 2* 5SING THE NEUTRAL ZONE TO OBTAIN MAXILLOMANDIBULAR RELATIONSHIP RECORDS FOR COMPLETE DENTURE PATIENTS * 0ROSTHET $ENT   n  &AHMY &- +HARAT $5 ! STUDY OF THE IMPORTANCE OF THE NEUTRAL ZONE IN COMPLETE DENTURES * 0ROSTHET $ENT   n "ARRENAS , /DMAN 0 -YODYNAMIC AND CONVENTIONAL CONSTRUCTION OF COMPLETE DENTURES A COMPARATIVE STUDY OF COMFORT AND FUNCTION * /RAL 2EHAB   n  .EILL $* LAYSHER + )DENTIFYING THE DENTURE SPACE * /RAL 2EHAB   n "OOK 2EVIEW $ENTAL (ARD 4ISSUES AND "ONDING )NTERFACIAL 0HENOMENA AND 2ELATED 0ROPERTIES %LIADES $# 7ATTS AND 4 %LIADES EDS (EIDELBERG 3PRINGER 6ERLAG "ERLIN   PP HB a %52   )3".    8 4HIS BOOK REVIEWS BONDING TO ENAMEL DENTINE OR CEMENTUM AND THE RELATED ADHESION MECHANISMS 4HE FIRST SECTION IS DEVOTED ENTIRELY TO ENAMEL BONDING 4HE FIRST CHAPTER REVIEWS THE LITERATURE CONCERNING BONDING TO ENAMEL AND

DISCUSSES THE ROLE OF TOTAL ETCH AND SELF ETCH ADHESIVES AS WELL AS THE INTERACTION OF GLASS IONOMER BASED MATERIALS WITH ENAMEL 4HERE IS SOME OVERLAP WITH THE NEXT CHAPTER THAT IS DEVOTED TO BONDING OF RESINOUS MATERIALS TO PRIMARY ENAMEL #HAPTER THREE LOOKS AT THE EXPERIMENTAL MODELS FOR EVALUATING BOND STRENGTH AND IDENTIFIES IMPORTANT VARIABLES #HAPTER FOUR ADDRESSES BONDING WITH WATER INSENSITIVE AND WATER ACTIVATED ORTHODONTIC ADHESIVE RESINS 4HE AUTHORS IDENTIFY THE EFFECTS ACCOMPANYING LONG TERM INTRA ORAL AGEING OF BONDED RESTORATIONS THAT MAY PREVENT MEANINGFUL COMPARISON WITH SHORT TERM BOND STRENGTH DATA 4HE WIDELY QUOTED PROPOSAL OF A PARTICULAR MINIMUM @THRESHOLD BOND STRENGTH VALUE FOR ORTHODONTIC BRACKET  $ENTAL5PDATE RETENTION IS WISELY REJECTED 0ART TWO IS DIVIDED INTO THREE CHAPTERS WHICH COVER „ "ONDING TO DENTINE SMEAR LAYERS „ )N SITU PHOTO POLYMERIZATION AND „ 0OLYMERIZATION SHRINKAGE PHENOMENA AND BONDING IN PROSTHODONTICS WITH CEMENTS 4HE

ADVANTAGES OF SIMPLIFIED ADHESIVE SYSTEMS ARE WEIGHED AGAINST THEIR SHORTCOMINGS ! SIMPLE BUT SCIENTIFICALLY SOUND CLASSIFICATION OF ADHESIVES IS PROPOSED WHICH CATEGORIZES PRODUCTS BY BONDING MECHANISM RATHER THAN BY @GENERATION 4HE SUCCEEDING CHAPTER COVERS THE POLYMERIZATION OF LIGHT ACTIVATED DENTAL BIOMATERIALS AND THE FACTORS GOVERNING SHRINKAGE STRESS 4HE FINAL CHAPTER IN THIS SECTION LOOKS AT PROSTHODONTIC LUTING CEMENTS AND PROPOSES A CLASSIFICATION BASED ON THEIR MECHANISM OF ADHESION TO TOOTH STRUCTURE 4HE FINAL SECTION OF THE BOOK REVIEWS THE STRUCTURAL COMPOSITIONAL AND FUNCTIONAL ASPECTS OF CEMENTUM AND DISCUSSES POSSIBLE FUTURE APPROACHES FOR BONDING TO THIS UNIQUE SUBSTRATE 4HIS WELL REFERENCED AND BEAUTIFULLY ILLUSTRATED CONCISE TEXT CONTAINS A WEALTH OF INFORMATION FOR ANYONE INTERESTED IN RESEARCHING THE SUBJECT !S SUCH IT SHOULD BE A WELCOME ADDITION TO ANY DENTAL LIBRARY ! # 3HORTALL 2EADER IN 2ESTORATIVE $ENTISTRY 5NIVERSITY OF "IRMINGHAM 3CHOOL OF

$ENTISTRY *ANUARY&EBRUARY